A LiFEJ-EIS'E'ORY STUDY
as THE swam: swam,

wascmus gmgcum VER58.C._G*_=_QR
wane?

Mfmfhebcgz‘aofmn.
mm STATE COLLEGE
Latter E. Ever
1954

 

 

II III IIIII I III IIIIII III III III IIIIII II IIIIII IIII III III II L

This is to certify that the

thesis entitled
A Life—History Study of the Bronzed Grackle,

QuiscaJus quiscula versicolor Vieil" ot.

presented b1]

Lester E. Eyer

has been accepted towards fulfillment
of the requirements for

M degree in Mg—

gig/UH» g b3 «92%

Major professor

Date February 26, 1951+.

0—169

 

 

 

- ‘3

f 1. 9 ‘
I“! . .5.
'- .1

 

 

A LIFE-HISTORY STUDY OF THE BRONZED GRnCKlE,

nuiscalus quiscula versioolor Vieillot

By

Lester Emery Eyer

AN ABSTRACT

Submitted to the School-of Graduate Stuiies of Liohignn
State College of “griculture and Applied Science
in-partiel fulfillment of the requirements

for the degree of

DOCTOR OF PHILOSOPHY

Department of Zoology

"’l 7.1
Lester nznez‘j; .9pr

The life history of tle bronaod grackle Quiscalrs lyis—

 

cula versicolor, was the sneiect of intensive stud” it the

 

vicinity of East Lansing, Michi;an, during 1331 and 1952.
Emphasis was placed on the nesting cycle, narticnlarlv of
those birds breeding in marshes and swamps. other phases

of the study included: (1) nest-nesting activities of fam-
ily groups, (2) the development of hand-reared birds kept

in captivity for a year, (5) food habits, based on the anal-
ysis of 20 stomachs and supplemented by a review of the lit-
erature, and (4) roosting and flocking of grackles in mixed
flocks of starlings and cewbirds in willow-thicket and manle—
tree roosts. As a secondary objective the literatwre was
reviewed for: (l) the complicated history of the taxonomy
and nomenclature of the genus Quiscalus, and (2) the dis—
tribution and migration of the snecies \uisc la, supplement-
ed by unpublished return records of 52 gr ckles banded in

the vicinity of East Lansinj.

The nesting cycle. Male

 

Michigan about mid—March. Conrtshit be ins when the females
arrive from 6 to 10 days later. In selecting a natc two to
four males compete for a single female bv: (l) nerfcrnin;
intimidation displays, e.;., bill-pointing and a challenge
song accompanied by a roughed-feather diSplay, and (2) 80-

companying the female on short flights away from the nesting

 

Lester fmery Eyer
area. The dominant male tenemes the mate after a week or
so of competition. No definite territorialism is evident.
In early April the female, accompanied by her mate, be—
gins hunting for a nesting site in the marsh. About mid-
April the female starts the nest, while the male Quards.
Jest buildin; is usually completed in owe weeks.

n a lB-square-mile area re-

H.

A survey of nesting sites
vealed: (1) that about half of the pepulation nested in
marshes and swamps and half in coniferous trees, (2) that
the average size of the marsh colonies was 6 pairs, while
that of the coniferous-tree colonies was 9.5 pairs, and
(5) that the population was 12.3 grackles per square mile.

’ Incubation, carried on by the female only, begins near-
ly three days after the nest is complete and lasts for an
average of 12.7 days. Roth male and female feed the YCHLS,
but only the female broods.

Out of 35 active nests the survival rate was 1.2'young
per nest. Two important mortality factors were had weathe
(25 per cent of eggs deserted) and predation (”0 rer cent by

natural enemies, 6 per cent by the investigator).

L

Hand-reared birds. The young male began to "sins" fol-
lowing the postjuvenal molt, but the females did not start
singing until December. The song of a mature bird was not
attained by the captive young. Althoroh the females begged

and postured before the male, cepulation was not observed.

\\

Lester Emery Eyer

OJ

In May one female shcwc signs of nest buildin;-—she picked

'1

up bits of string, J ass and other material availahle with-

in the cage.

Boosting. Before nesting both male and female wrackles

x)

 

roosted in a willow thicket with starlings, cowbirds, and

red-wings. (The roostin-

g.)

population, however, was predom—
inantly starlings.)But as soon as incubation was started,
the females rcosted on the nests while the males continued

to use the same willow-thicket roost.

 

 

 

BRtlhidD
olor Vieiilot

canons ,

 

a LIFE-HISTORY STU HY OF THE
uiscalug :uisc ula ver rsic
By

Lester hmery Eyer

Submitted to the School of Graduate
State College of agriculture and
in partial fulfillment of the

a -
' x :‘i ' ‘r -. .
:cr the dealee

DOCTOR

1 ‘ r\ y ‘ -\0
Utii aI‘ttneht \‘L

Year 1954

Utudie of
applied ocien
requirements

ich iga n
es

of

CF PEILOSOPHY

ecology

Pr— 1/- 5'7
Q <55: {a

L L’ “I -HVT
loge
INTRODUCTILN . . . . . . . . . . . . . . . . . . . . . . l
lJurro see . . . . . . . . . . . . . . . . . . . . . . 1
500118 0 . . o o . . . . o . . . . . . o . . . 0 2V

Notorie l and Lethods . . . . . . . . . . . . . . . .

‘J

acknowledgments . . . . . . . . . . . . . . . . . . 1
TAXONOLCY 1ND IEL‘LI‘ E. I" 3171;}, . . . . . . . . . . . . . . 5
Taxonomic Relationshi s . . . . . . . . . . . 5

O 0
C.
H o
(n
O
C.

y,

(1
<1
(I:
'1

(I

11
J
O
H
O

S

Nomenclatural history of ~buiscolus

l

DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . 14
Historical Background . . . . . . . . . . . . . . . 14
Breeding Range of J. 3. versisolor . . . . . . . . . 17

Lcological distribution . . . . . . . . . . . . 18
Distribution in Licligan . . . . . . . . . . . . 19
Winter Range of J, g, versicolor . . . . . . . . . . a1

 

 

PvEIGRfriT-IC N. c o o o o o . o o a o o o o o o o o o o o o o 6:15
SP I' i Hg 0 o o o o o o o o o o o o o o o o o o o o o o a; f)

Bdll O O 0 O 0 O O O O O O O O O O 0 O O 0 O O 0 0 :vl‘t'

THE I\IJQ.'3T11¢G CYCLE . . . . . . . . . . . . . . . . . . . 13";
Introduction . . . . . . . . . . . . . . . . . . . 54
General Lcologicol Consideretions . . . . . . . . . 37

Th5rsiogrezhy . . . . . . . . . . . . . . . . . . 87
Climate and westher . . . . . . . . . . . . . . 39
Biotic community . . . . . . . . . . . . . . . . 30
General habitat of Trowbridge Narsh . . . . . . 40
La ting . . . . . . . . . . . . . . . . . . . . . 45
hffiVfll at the breeding grounds . . . . . . . . o
Territory . . . . . . . . . . . . . . . . . . . 40
Kind of mating relationshio . . . . . . . . . . g7
Song disclay . . . . . . . . . . . . . . . . . .
Uses of song display . . . . . . . . . . . . . . c-
Courtship flight of male . . . . . . . . . . . . 5l
Formation of pairs . . . . . . . . . . . . . . o;
The Nest . . . . . . . . . . . . . . . . . . . . . o
Nesting site . . . . . . . . . . . . . . . . . . 56
Nest building . . . . . . . . . . . . . . . . 59
weather in relation to nest building . . . . . . 64
Nest structure . . . . . . . . . . . . . . . . . 65
.Uurability'cfi'tflue ne est . . . . . . . . . . . . . 70

0pc» \
J‘D

J

H

'I

   

Survey of nesting
Literature . . . .
“gg—laring, Incubation
ng—laying . . .
The egg . . . .
Incubation . . .
Hatching . o . .
Growth and bevelogment
ht 11;} tChing o .
Day of hatching to
Nest leaving . . .
Growth . . . . .
Nesting Su; cess and Lo
Parental Care . . .
Brooding . . . . .
Feeding . . . . .
Nest sanitation .
Defense . . . . .

PCST-NESTIL “C'T VITIES .

IIJ'LI‘TD-REARED YOLJG . . .
Growth . . . . . . .
Plumage . . . . . . .
Feeding . . . . . . .
Voice . . . . . ..
Sleeping . . . .
Nest- buildir g urge . .

FOOD 1'1th FEAJDIN'G 1:1“; “1 "S o
FOOd O O O O O O 0
Food of nestlings

stomach analysis of Has

Feeding Habits . . . .
structure and use
Use of the feet .
Wading . . .

.7

Flying gull-l ike fo r fo

Dunking food . . .

o O
and
O O
O O
O O
O O
f 'L‘
.L
0 .
ttue
0 0
0 O
r
O
O 0
0 O
O O
0 O
0 O
O 0
O O
0 O
0 O
O O
O O
O O
O O
0 O

Attacking other birds

ROOSTING AND FLOORING .
Spring Noosting .

Early sirirg .

Late syring .

The roost .

Going to the

roost

Cf th

arrival at the roos

Departure from the

Summer Boosting .

Pic-+0

. .
td

. .
O O
O O
O O

O

O
O o

m

cf.

6213 Ian

0 O C
O O O O

O 9 O
O O O 0
O O O O
O O O O
0 O O O
O O 0 O
O 0 O C
O O O O
O O O O

O O O
0 O o o
O O 0 C
O 0 0 O
O O O O
O O O C
O O O C
O O O 0
O 0 O O
O O O O
O O O O
O O O O
. O O O
O O O O
O O O O
o O 0 O
O O O .
crackle

0 0 O O
O 0 O O
O O O O
O O O 0
O O O O
O O O O
O 0 O O
O O 0 O
O O O O
O O O O
O O O O
O 0 O O
O 0 O O
O O O O
O O O O
O O O I

Page
7;
75

'7".

u
\1

7&

EB
89
V‘U
100
100
105
107
107
109
114
115

Willow—thicket roost
Maple-tree roost
Flocking . . . . . .

ELEV/Iv: 4' 1R Y o o o o o
oik-PP BID E: o o o o 0
lists
Tables
Plates

LITERATURE CITED

 

 

1-wm no A \r W‘
11a1 or rlGnHao

Breeding range of the purple graokles, guis-

q I -
CGJJJS cr11s<n11 :. . . . . . . . . . . . . . . . 11

 

 

 

l‘ ost- glacial disp ersior of the Florida gra ckle,
ggiSUalus quiSCIl: -uiscu1a, and the bronzed
grackle, uiscalus ggiscula versicolor. . . . 16
Lirnxer rangyz 1? ti; tixui7ed (grastl~ , Quifiy:alus

 

quiscula versicolor. . . . . . . . . . . . . La
Spring migration of the bronzed graokle. . . an

Comparison of effects of migration on relative
abundance of bronzed grackles throughout a year
at t'I’V'O locations 0 o O O O O o O O O O O O O 0 L9

The location of recoveries of bronzed grackles
banded at East 1&1nsing, Lansing, an< lake Odes—
88, MiChigan. o o o o o o o o o o o o o o o o 3Q

Trowbridge Larsl shoeing vegetation zones and
surrounding habitat. . . . . . . . . . . . . 35

[Maxim 111m and minimum temyeratures during nest
buil in* at Trovbridge harsh, lQSl. . . . . . 66

Naximum and minimum temperatur s during nest
building t T owbridge Naish, 195;. . . . . . 67

Nesting population of bronzed grackles in the
vicinity of East lensing, 1955. . . . . . . . 7n

A record of attentive ar C inattentive geriods
of two females incuta tin . . . . . . . .

C,\]

The correlation of nest des rtion with tem'er-
ature aLd 1.reciiitation at Trowaridge L arsh,
1951. o o o o o o o o o o o o o o o o o o o o 86

The correlation of nest desertion with temyer-
ature and precipitation at Trowbridge Narsh,
and Forest Road colonies, 1952. . . . . . . . 87

Daily amount of growth of nestling bronzed
grackles. . . . . . . . . . . . . . . . . . .lOl

 

 

Fig.

fig.

16.

17.

18.

21.

feeding freiuency of bronzed grackles at Nest
45 with four nestlings eigh and hi e days
Old. 0 O O O 0 O O O O O O O O o O O O O O O

Needing frequency of bronzed grackles at Ne:
26 with four nestlings nine and ten days old.
Feeding frequency of bronzed grackles at N'st
25 with three nestlings and one fledgling
near by. 0 o o o o o o o O o o o o o o o o o

(1’

average feeding frequency of bronzed grackles
at Nest 25 with four young during the last
three days before leaving the nest. . . . .
Daily amount of growth of young bronzed
grackles hegt in captivity. . . . . . . . .

Correlation of activities of blackbirds (bar)
going to roost with time of day and light
intensity (curve), Narch, 1955. . . . . . .

Correlation of activities of
leaving the roost (bar) with
and light intensity (curve),

blackbirds
tinxe of (L1y

April, 1952. .

"9

110

111

111

la:

1&5

 

 

'7-7'r

“Ifrl‘lx‘ 1"!“I “
.Li iJ'L-/'FU_..V;~

Many of the rare tires of Perth “Loris“ have been ir-

v:stigated 'uite thoroughly by students of arritloloir

I ‘
1 J.) 9

while some of the comror birds haVe } en neglected in this

(1‘

resiect. The grachles are in the latter group. although
it is true that earlier ornithologists have examined the
feeding and roosting habits as tall as the taxonomy of the

grackles, only limited studies of the life history of this

species haVe been published.
Purpose

The primary purgose of this investigutien was to learn
more about the life history of the bronzed grachle, guis-

calus ggiscula versicolor Vieillot, in Niehigan and to aa—
semble facts, both new and old, about its habits. In this
study life history is unferstood to mean the annual cycle

of events in the life of the bird. Steps in the nesting

cycle such as mating, nest buildin:

g),

incubation, grovth
and development of the young, as well as feeding, roosting,
flocking, and migration comprise the bird's life history.

n secondary aim was to assemble and sunrarize from the
literature pertinent data concerning the taxonomy and dis-

tribution of the grackles. The writer felt a need for in-

 

 

 

eluding such background information at~ut the grachles in

J
C?
rv
t.)
1'

'l
{D
O
H
(D
(I)
0

order to give a more comjlete picture o:
Scope

The organization of the material has been governed by
the chronological order of events. The background inferna-

‘

tion of taxonomy and distribution is place; first. Then the
life-history study is presented in the following order: mi-
gration, nesting cycle, post-nesting activities, hand-reared
birds, food and leading habits, and roosting and flocking.
Field investigations mere conducted for two spring and
summer seasons in Last Lansing and the vicinity, lngham
County, Michigan. The nesting cycle mas studied at a snail
marsh from the last week 1f harsh to the riddle of June in

1951 and from the second week of Narch until the -:rst .ee;

of June in 1952. ho ever, additional measurements of grovth

were obtained at two other similar glaees during the lE5t
season. In connection with the nesting :ycle, a survey of
the nesting populaaion was made by loosting no ting reas

and counting mated pairs in a la—s;uwre~mile area. Hand—

CI]

reared young were kept from may 15, 195; to august, 195 .
Hoosting observations were made at a nillow thicket near a
small lake during the 1952 sprinr and summer seasons. as

part of the food-habits study, stomachs of nestlings, juve-

nals, and adults were examined in 1951.

 

and hetlods

haterial

(.3

nt the marsh where the main iortion of this i

Q

tion was conducted, e la—foot otserVaticn tower ML

structed to afford a vantage stint stove the lush

observing activities If the birds QVcr tre entire
(Plate 1, Fig. A). n blind was affixed to the top

tower.

Leasurements of growth in weinht und in the l

the bill, wing, and tarsus tiken. For weighi

'vha' '3 l" {3

spring-balance, sinqle—platforn, dietetic scale

 

nvestiga-
S COE—

lchl for
area

of the

ength of

(‘0

6':

C“
L:

n

sensitive

to one gram was used in the field. heesurements of the
bill, wing, and tarsus were taken as follows: bill, by
placing one goint of the dividers at the tip of the water
mandible and the other along the midline of the culmen at
the posterior edge of the horny lurt of the till; filefl: by
placing it on i ruler and measuring from the bend (cargsl

l|'\

joint) to the tip 3f the fleshy E“

to the tip of the longest primary ,in feether in o
lings; tarsus, by placing ore ruint gf tie divider

tibio-tarsal joint and the other at the agex of a

‘ o
Okln

‘1

at the junctior of the t

(D

shaped crease in th
the toes.

Light intensities were measured with a Uesto

1 0

meter, model 715, by holding it directed toward tl

“11 photographs were by the author.

rt in very young

.e

rirds or
1der nest-
ut the
wedge-

y.
1 L

arsus rit

exgxq sure

zenith.

 

 

kany peoyle
ways during this stud
acknowledged.

thanks to Dr.

'\
I

advi' in the study a

e

manuscript hove been

knowledcment is also

utment

J o StuCK f': I S ‘-.:‘,N

,..
W.

L

of Michigan dt.t

CF.

m1ssion to lse Iis ta
Ur. Fe er 1. lack far
the study or the cell

3 ° .‘ ’9 t . ‘ .
for his ‘118 s consta
staty, 14.7“or ier h-
’ '-" r‘ ' ‘ t‘ a" :

K‘f the 11.x.411'le/J .LDE.

George J.

.9 , r} I». I ,e . . r~

J and scab eerVice is here
. I .1 . 4. ‘ o
iter tieres to eiyress his

"'.'L.1]-l LOB ,

nd guidance e

of ;reet material heir.

1

CUE

J.

o0

to Dr. Halter h. lorofsk,

’

t* Dr.

fCI‘ alt

regaration o

(O

43
.L

Gr.tcful

some glant specim ns, to Yrofosso
stions in tie use 6“ th; ‘aIfiito r
Zeje, AL‘ to hr. 6. U. Ludvi; fol
nding rectrds. sincere th rks are

c’
‘l

3111:

0 o
s in; enli.3;: hJJ. siruicre .1.
.L ' - . .'. ..‘ -vr ‘
rt intera.a t cl\r:r,tl~:
a . ' A Q ~ \._ ‘ ‘ - _ w
-1' .L- 'Jiur'i J puf- W.) .K :3,

' I

(J

Ur. Don M. Mayne for advice on

 

TAXONOMY AND NOMEKCLAIWRE
Taxonomic Relationships

The genus Quiscalus belongs to the family Icteridae.
This strictly New World family is widely distributed in
North, Central, and South America and the adjacent islands.
It is a fairly large family having 35 genera (Hellmayr, 1957)
and 88 species (fiayr, 1946). Quiscalus is confined to North
America north of the Rio Grandc 'illey and the adjacent is—
lands.

There are three genera of icterids in North America
north of Mexico which are commonly called blackbirds and of-
ten have been called grackles in the past. In addition to
having names which are similar, they are all the more confus-
ing to the casual observer because of similar color charac-
teristics. All are black with iridescent colors of metallic
hues on the head. Euphagus, which contains the smallest
species, is the genus to which the.robin-size Brewer's black-

bird, E, cyanocephalus, and the rusty blackbird, E. carolin-

 

us, belong. The tail of these species is short and rounded,
never V—shaped. The female is only a little smaller than

the male and duller in color. Quiscalus contains medium—

 

sized forms, the nurple grackles, with long graduated tails.
They are 11 to 13 inches in length. Males depress the cen—

tral tail feathers to form a V-shaped tail while in flight

 

 

during the breeding season. As in Eunha us the female is

—~.__.l._

nearly the same size as the male and somewhat duller in
appearance. Cassidix, the boat-tailed grackles, contains
the largest forms, that is, the males are much larger, aver—
aging 16 to 17 inches, while the females are about the size
of a male purple grackle (15 inches). The tail is long and
graduated and, in the case of the male, is V—shaped during
the breeding season.

As currently defined (1955) in the Nineteenth and
TWenty-third Supplements of the American Ornithologists'
Union (A.O.U.) Check—list, the genus Quiscalus is represent-
ed by a single species, guiscula, which is divided into
three subspecies as follows:

Florida grackle, Quiscalus guiscula guiscula (Linnaeus)

 

Purple grackle, Quiscalus guiscula stonei Chapman

 

Bronzed grackle, Quiscalus quiscula versicolor Vieillot.

 

There is a very close similarity in the appearance of

these three forms of the ”purple grackle."

A brief descrip-
tion of each will aid in distinguishing them.

The Florida grackle, g. 1. guiscula, is the smallest
form. It inhabits the southeastern part of the United
States mostly along the Atlantic and ¢ulf coasts. The head
color of the adult male varies from a purplish bronze to a
violet. Head color, however, is not considered to be a re-

liable characteristic for separating the three subspecies

(Ridgway, 1902:214). The most useful color characteristic

 

is that of the back, scapulars, and sides of the breast,
which in the Florida drackle is a dark olive-green or dull
bottle green color with concealed iridescent bars of other
metallic hues.

The slightly larger purple grackle, g. g. stonei, is a
highly variable form, occupying the area north of the range
of guiscula, from the Atlantic Coast to the eastern slope of
the Appalachian Mountains. The color of the back, scapulars,
and sides varies from a bronzy purple to an olive-green or

even a bottle green. Concealed iridescent bars on the back

distinguish it from versicolor and the larger size separates

 

it from guiscula.

The bronzed grackle, g. g. versicolor, is the most wide—

 

ly distributed form (Fig. l), breeding over the greater part
of North America between the Rocky Mountains and the Appa-
lachians and north to the tundra. It is about the sam size
as stonei, the purple grackle, but differs in color from
both guiscula and stonei. It has a uniform bronze color over
the back, scapulars, and sides. The lack of iridescent col-
or bars to interfere with the bronze color is the most help-
ful distinguishing characteristic.

A fourth subspecies, named g. g. ridowavi by Oberholser

(1919:269), inhabits a zone of intergradation between stonei

and versicolor. This subspecies has not been recognized by

 

the A.O.U. Check-list Committee to date (1953). According

to Chapman (1956:415) it possesses color characteristics of

"
’O
’

 

LEGEND _______
Q.qquisculg [11m
Q's-W E
Q's-$191121 , ., .0
Qqadgmnyl ‘ - - -- ‘1'. -21»

MXridgwagim

Repert Locah'on a

Fig. l. Breeding range of the purple grackles,
Quiscalus guiscula .

 

 

A

‘4‘

both forms. The back and rump are a rich bronze color with-

out iridescent bars, much as in versicolor. The wings have

 

the color of stonei but lack iridescent bars on the scapu-
lars. The sides are a rich bronze with a few iridescent
bars. This subspecies, then, has the bronze color of ver-

sicolor and the wing color and iridescent bars of stonei.

Nomenclatural History of Quisoalus guiscula versicolor

 

The nomenclatural history of the three subspecies of
guiscula is interesting but confusing. Since a comprehen-
sive review is beyond the scope of this work, the following

account merely sketches the history of how the bronzed

 

grackle received its name, Quiscalus quiscula versicolor
Vieillot.

The Europeans who first came to America often applied
the names of birds familiar to them in the Old World to sim—
ilar birds over here. Mark Catesby (1751) was no exception
(Allen, 1951:465). He described and painted a grackle while
he was in South Carolina. It must have reminded him of a
blackbird-like crew in Europe, a member of the family Cor-

vidae, for he called it "The Purple Jack-Daw, Monedula pur-

 

puggg," Perhaps this similarity to the jackdaw, which in
reality is a crow, was the source of the name "crow black-
bird," another name by which the grackle was known.

When Linnaeus classified North American birds, he used

some of Catesby's descriptions in his classification. For

 

 

 

 

lO

example, he used the description of Nonedula purpurea for

 

his Gracula guiscula. Thus, he was the author of the
species name guiscula which is currently in use. The name
grackle is probably the anglicized word derived from this
genus name Gracula (Trotter, 1909:552—155). According to
Trotter (1909) the name "purple graokle" was used by Wilson,
this being its source in the current vernacular of ornithol-
ogy.

Vieillot collected and described a grackle from the

United States and called it Quiscalus versicolor. Accord-

 

ing to Wilson (1876:335) Vieillot chose the name Quiscalus
to apply to the American bird in order to avoid confusion
with a bird inhabiting India that was already called EEEET
313. By his very choice of this name for the genus he shows
there was a question in his mind as to what kind of a tire
it was. (Quiscalus is derived from two Latin words, namely
9223, which means who, which, what, and gualis, which means

of what sort.) The name versicolor means varied in color.

 

Vieillot's Quiscalu§_is in current use instead of Catesby's
Monedula or Linnaens' Gracula because both of the latter

are preoccupied. The subspecies name versicolor is also

 

cur°ent1y used.

The authorship of Quiscalu§_quiscu1a versicolor is

 

therefore established. Vieillot supplied Quiscalus versi-

.L

 

32193 and Linnaeus supplied the species name guiscula. How-

ever, these names were applied to the purple grackles of the

 

 

 

ll
eastern states, of which there was only one recognized form.
Ridgway (1869:154) was the first to separate the bronzed
grackle from the eastern and southeastern purple grackles.

He described it and named it Quiscalus aeneus and designated

 

Mount Carmel, Wabash County, Illinois, as the type locality.
The question as to whether the bronzed grackle should
be regarded as a species or merely a subspecies soon arose.
Six years after Ridgway had listed it as a full species
Baird, Brewer and Ridgway (1375:219) listed it as a sub-
species of guiscglg, Steineger (1885:33) in a foot-note re-

ferred to the bronzed grackle as Quiscalus guiscula aeneus.

 

The A.O.U. Check-list (1886) listed the bronzed grackle as
Quiscalus guiscula aeneus.

The bronzed grackle was known as g. g. aen us for 60
years. During that time, however, the taxonomic status of
the species guiSCula was examined carefully by several or-
nithologists. Wetmore (1939:250) who had examined Yieillot's
type Specimen housed in the Museum d'Histoire Naturelle in
Paris said he believed it was a bronzed erackle and n t a

3 Q
purple grackle as had been supposed for so many years. He
made the following statement about it:

. . . there is no question as to its identification as
indicated, and there seems to he no doubt that it is the
basis of Vieillot's description. . . . The name of the
Bronzed Crackle, therefore, becomes Quiscalus versicolor
Vieillot, if it is considered a distinct species, or
Quiscalus versicolor versicolor, if the belief is held

that it is conSpecific with the eastern and southern
grackles of this group.

 

 

12
In viewing the taxonomic status of the genus Quiscalus Wet-
more believed that there were two species, one the bronzed
grackle with no subspecies, and the other the purple grackle
with the hybrid (ridgwayi) ocearring where the ranges of
these two species overlap.
In 1944 the A.C.U. Check—list Committee followed Wet-
more’s suggestion and listed the bronzed grackle in the Nine-
teenth Supplement (1944:460) as Quiscalus versicolor
Vieillot, thus giving it specific rank.
The bronzed grackle did not have the status of full
species for long. Some who agreed with the Check-list Com—
mittee's decision about this changed their minds later.
Sutton (1945) was one who did just that. He had this to
say about it:
. . . But I now believe I was wrong, and I believe the
Committee's decision—~whatever the basis therefore-~is
wrong, for when two or more anatomically very similar
forms have the same color-pattern, call-notes, courtship
behavior, nesting habits, roosting habits, molts, foods,
etc., and interbreed indiscriminately wherever they oc—
cur together, they certainly must be called the same
species, if the term is to have a truly biological mean-
ing. . . . It is interesting, and desirable, to consider
the possibility that the Bronzed Crackle may have budded
off and become a full separate species; but so long as
the bird itself recognizes no essential difference be—
tween itself and other forms of its genus with which it
comes in contact during the breeding season, ornithol-
ogists may well accept its own obviously satisfaccory
decision in the matter and name it accordingly.

Three years after this statement was made the A.O.U. Check-

list Committee made the following change in the TWenty-

third Supplement (1948:442): "Quiscalus versicolor Vieillot,

 

 

15

the Bronzed Crackle, again listed as Quiscalus guiscula_ver-

 

sicolor Vieillot."

 

 

 

l4

‘. mn-
‘ . ‘.—'
.L‘IQ J..L

IBUTICN
Historical Background

The exact place of origin of grackles is not known be—
cause there is not enough direct evidence to trace their ge-
ological history. However, on the basis of present distrib-
ution most ornithologists believe that they are of neotrop-
ical origin. Bond (1948) claimed that grackles probably
originated in southern North America and Spread to Central
America and more recently to northern South America.

Chapman (1955a, 1935b, 1936, 1959, and 1940) has ad-
vanced a theory to eXplain the present distribution of Epigf
calus quiscula in North America. According to his View two
groups of this species were isolated one from the other dur-
ing the last glacial period, but following the retreat of
the ice the two groups united again. He explained that as
theice advanced southward into northern United States, the
grackles, as well as other animals, were forced to retreat.
Those located east of the Appalachian Mountains withdrew to
the Florida region, while those west of the Appalachians
took refuge in Texas and northeastern Mexico. The two
groups of grackles, presumably morphologically alike, at
first were isolated from each other for a long period—-long

enough to allow two morphologically different forms to

15
evolve. Those confined to the southeastern area became the
subspecies guiscula and those restricted to the southwestern

area became the subspecies versicolor.

 

During their period of isolation the two groups of
grackles were subjected to different types of climate (Hunt-
ington, 1952:165): guiscula in the Florida region to a
humid climate with moderate temperature changes, and 1gpgi-
gglgg_in the Texas—Mexico region to a drier climate with
more extreme temperature changes. Huntington believed that

the fact that versicolor was subjected to such changing con-

 

ditions has contributed to its broadly adaptive nature and
to its migratory habit. By contrast, guiscula appears to
have been less aggressive in occupying new territory and
has not developed the migratory habit to the same extent as

versicolor.

 

Following the retreat of the ice, Chapman (1955az22) ex-
plained that the grackles extended their range northward

(Fig. 2). Versicolor, on the one hand, spread rapidly and

 

extensively from the southwest to the east and north over
much of North America, and guiscula, on the other hand, ex—
tended its range from the southeast retreat westward and
northward along the coasts.

The subSpecies stonei, according to Chapman (1936:405-
407), was an off-shoot of guiscula. He accounted for the

speciation of stonei in this way:

by»

24.0
1 0
so ”9 m' 100' so' ' '

 

 

 

0 ~. ,fi (“3. thi ({q .scula
, r. :' .. e I ,
I”: 2"“); \"f .l 2.2:?"
. z . .3. ‘_ \. 2.1.} s
\w‘ Q (tversacolq .;.-..-- 7"“. . - .vo’"
‘. - . \.~ ,0
xi. as. .
- . , . 0 ¢-—’
~~.§.- "Z“: BL/‘OQ' 0c:
'0- ' ' “'_°:'c——' ‘ v .Q
.. ‘0“- ---""’- .
- b.-- -----.-------- ----- 1 a .

 

 

I \wii, ‘7’

Fig. 2. Post-glacial dispersion of the Florida greckle,

Quiscalus guiscula guiscula and the bronzed grackle, Quiscalus
guiscula versicolor.

 

 

17

. . . the changed population conditions incident to ex—
pansion of range have permitted these mutational char—
acters to find expression in stonei, which we may pro-
visionally consider as neither the product of its envir—
onment nor of hybridization, but of heritable, individ-
ual variation or mutation.

Huntington (1952:162) did not agree with Chapman's eXplana-
tion of the speciation of stonei. He was convinced that
stonei W. . . is the product of both its environment,
through selection, and hybridization."

The subspecies ridgwayi was the product of hybridiza-

tion between stonei and versicolor according to Chapman's

 

View. Huntington considered ridgwayi, as well as stonei,
to be intermediate forms resulting from hybridization be-

tween two end products, viz., guiscula and versicolor.

 

Breeding Range of Quiscalus g. versicolor

 

The bronzed grackle has extended its breeding range

over a large portion of North America (Fig. 1). Its present
range extends northward from the Rio Grande valley along the
eastern slopes of the Rocky Mountains where it is found up

to an altitude of 5,000 feet (Drew, 1385:16), north to Great
Slave Lake, southeast across the forested part of Canada to
southern Labrador, south to central New England, west to cen-
tral New York, southwest along the western SIOpes of the Ap—
palachians to southwestern Louisiana, and southwest along

the Gulf Coast to the Rio Grande valley. Vagrants of 333;

sicolor have been observed beyond the normal range in the

 

18
west and north. hlcorn (1940) reported findin' 1 dsdd
bronzed grackle at Fallon, Nevada, which is over 600 miles
west of the breeding range. Weydemever (1932, 1954) ob-
served one or two bronzed grackles on different occasions
in northwestern Montana west of the Continental Divide. An-
other interesting straggler was a male bronzed grackle taken
at Wainwright, Alaska. Bailey (1948:291), who has this
specimen in the Colorado Museum of Natural History, believes
this is the only Alaskan record. Macoun (1903:411—412) re-

ported grackles to be stragglers as far north as Hudson Bay.

Ecolowioal distribution. The vastness of the breedinv
_____.h.__. b

 

range of versicolor becomes more apparent when one real-

 

izes the fact that several major biotic communities are in-
cluded. The major biotic communities occupied, including
their successional stages and ecotones, are as follows: the
Desert Scrub Subclimax of the Rio Grande valley, the Grass-
land Climax of the Great Plains, the Deciduous Forest Climax
of the Mississippi basin, the Deciduous Forest-Grassland
Ecotone of the prairie region, the Coniferous Forest—Grass-
land Ecotone of southern Canada in the west, and the Conif—
erous-Deciduous Forests Ecotone of southern Canada and north—
ern United States in the east. Stragglers are found in the
Tundra—Coniferous Forest Ecotone of northern Canada. In
some of the southern states, where there are islands of the

Oak-Pine subclimax, bronzed grackles are also found.

 

 

 

 

 

19
The distribution and the abundance of the bronzed

grackle varies from one part of the range to another. For
example, it is more evenly distributed and more abundant in
the Coniferous and Deciduous Forest Biomes than in the
Grassland Biome. The bu k of the population is found in
the deciduous forests of the Mississippi basin, the Great
Lakes and the St. Lawrence valley, in which part of the
range it is quite evenly distributed. Here too, where agri-
culture and cities have changed the original forest condi-
tions, it frequently nests near farm dwellings, and in cem-
eteries and in parks. Its numbers decrease farther north
in the western part of the Coniferous Forest Community and
it is still less common in the central and eastern part of
the same Community. Within this northern part of the range

versicolor is found more frequently in swamps and along the

 

borders of lakes and streams. In the Grassland Community
grackles are largely limited to the vicinity of water and
the dwelling places of man. They frequent the river valleya
sloughs and marshes, irrigation ponds and canals, as well

as ranch dwellings and towns.

Distribution in Michigan. The bronzed grackle is com-

 

mon throughout most of the Lower Peninsula of Michigan,
fairly common in the Upper Peninsula, and fairly common to
common on some of the islands of the Great Lakes, but rel-

ative abundance may vary from one locality to another.

 

 

20
This is due to the gregarious nature of the bird during the
nesting season and later during flocking.

Concerning the distribution of this species on the is-
lands of the Great Lakes, Ford (1952), who visited 20 islands
in northern Lake Michigan, the Straits of Mackinac and Lake
Huron at the mouth of the St. Mary's River in July, 1931,
observed grackles on only one island. He did not state
.which island that was. White (1895:225) reported bronzed
grackles to be abundant during migration in September on
Mackinac Island. Wood (1911:99), on the authority of the
[lighthouse] keepers at Charity Islands, Lake Huron, re-
ported this species to be a common Spring migrant. Van Tyne
(1925) noted that bronzed grackles were "fairly common" dur—
ing the months of June, July, and August on the Les Cheneaux
Islands of northern Lake Huron. The sane writer (1948:108)
stated, "Bronzed Grackles were common at St. James, Beaver
Island, in 1957.” He did not report any from Squaw, Trout,
Gull or Hat Islands, but learned from Arthur E. Staebler
and Leslie D. Case, Sr. that bronzed grackles were near the
main settlement of South Manitou Island in June, though none
were reported from North Manitou, South Fox, or North Fox
Islands. The present writer visited Beaver, Garden, Gull,
Hat and Shoe Islands on July 1 and 2, 1952, and found grack-
Ies on Beaver Island at St. James, but did not observe any
on the other islands. The bronzed grackle has been report-

ed from Isle Royale both in the Spring and in the fall

 

21
(Wood, 1951:440-442). It has, therefore, been established
that bronzed grackles occur on the following islands of the
Great Lakes: Beaver, Charity, Les Cheneaux, Mackinac, Isle

Royals, and South Manitou.

Winter Range of Quisoalus q. versicolor

 

 

Bronzed grackles spend the winter months, from late No-
vember until mid—February, in one of three parts of the win-
ter range: (1) the lower Mississippi valley; (2) northeast-
ern Mexico and a small part of Texas; (5) the southern
states east of the Appalachians (Fig. 5).

The Mississippi valley from southern Illinois south to
middle Louisiana and Mississippi is the portion of the win—
ter range where most of them stay. However, grackles are
observed nearly every winter in the more northern parts of
the range. Here they are reported to be few in numbers in
the eastern half of Kansas and Nebraska, the southern part
of Minnesota, Wisconsin and the Lower Peninsula of Michigan,
the Great Lakes area in Ontario and the southern New Eng-
land States.

Cooke (1888:175) pointed out an interesting fact about
the winter range of the bronzed grackle. He noted its com-
plete absence over most of Texas. It seems to pass over
that state and spend the winter in northern Mexico. The

limits of this range have not been reported.

 

 

 

Fig. 5. Winter range of the bronzed grackle, Quiscelus
quiscula versicolor. Dots show approximate locality where
this species has been reported. Coarse cross-hatching de-
picts part of range where they are occasionally found in the
winter. Fine cross-hatching represents the location of the
bulk of the winter population.

 

 

25

A few of the bronzed grackles that nest in the north-
eastern part of North America spend the winter in southeast-
ern United States. They have been observed during the win—

ter months in southern South Carolina, Georgia, and Alabama.

 

 

 

1‘le GRaTI 0N

{h9ring

Bronzed greokles spend the months of December and Jan—
uary on the winter ranpe located in southern United States
and northeastern Mexico. They are most abundant elorg the
Mississippi River and its tributaries. here they roost in
large flocks at night and range OVer the countryside in
search of food during the day. There is little evidence of
population change during these winter months.

At the first signs of spring in early February the num-
ber of grackles begins to increase in the southern parts of
the United States. This general increase can be traced
northward week by week as winter gives may to spring. Fig. 4
shows the approximate iosition of the v nguards of spring
migrants, drawn from reports made by observers for the past
60 to 70 years.

The first migrants that leave the winter range in north-
eastern Mexico arrive in Texas atout the end of January or
in early February (attunter, 1892:258). In the lower kiss-
issippi valley, however, the first migrants do not leave un-
til the first or second week of February.

as spring opens northward, migration is accelerated up

the MississipLi valley but proceeds more slowly across the

 

 

 

 

    

LEG END

Range boundarlj—. _ . __

 

Daft Position
Extrapolatcd D-P ------

Report location .

Fig. 4. Spring migration of the bronzed grackle.

 

 

Greet Elaine and the foothills of the Rocky Nountuirs.
Cooke (1888) noted that grackles in the Mississipgi valley
vere at latitude 44945' by terch 25 lot only at latitude 4f
over the Great Plains at about the Same date. This differ-
ence appeers on the may (Fig. 4) as a downward swing of the
date-position lines over the Greet Elsins. a possible ex—
planation of this apparent leg of northward yrogress is that
grackles tend to follow river Valleys during migration (kc—
Cann, 1951:175; Terkins 1952:90). Presumably those that
spread over the Greet Tleins begin their migration in the
lower Mississipyi Valley. Assuming that they do, then those
which move northwesthrd along the tributaries of the Miss-
issinpi will not he at the same latitude on a given date as
those which have continued northward up the Mississippi.

The kississippi River v lley is the msir thoroughfare
between the Rocky hounteins end the Aspelachian Mountains
for migrating bronzed grackles. Tributaries of this river,

such as the Ohio and Wabash Rivers, er

G)

followed, ir part,

by those birds going to the Great Lakes region. Grsckles
that breed in northern and northwestern Cufiade probably en—
ter that country from the upper hississiyri system. Cooke
(1915:445) pointed this out When he exsmired the migration
route used by birds in the valley of the heckennie. his line
of reasoning is clearly set forth in the following quotation:

It is evident that the westernmost breeding birds, utose
that summer in the Mackensie Valley, must have reached

 

 

 

*1

their breeding grounds from the southeast by ray of the
Mississippi Valley.

The cause of the choice of this route is easily
found in the conditions of moisture and woodland. All
these Species are either lovcrs of damp forests or of
moist meadows and marshy lakes. Their favorite surround-
ings extend in the United states not farther west than
eastern Ka see and western Minnesota. On arriving at
Manitoba, the dry plains that have teen ; barrier on
their left for n e lest thousand miles, become fetter
Watered and interspersed with groves and soon these
groves unite to form almost continuous well-watered for-
est-~a gonuire birds' paradise. Attracted ly the early
season and abundant food supply, the birds turn north—
westWard and settle for the summer in the valley of the
Mackenzie.

Cooke listed the bronzed grackle among 18 species that use
this route, but added that this would be difficult to prove,
since it also ranges over the Gr‘et Plains as well.

According to WOOd (1906:156) bronzed grackles, among
other early hardy migrants, do not come to Michigan at a
stated time each year, ". . . but are gOVerned in their mig-
ration to a certain extent by favorable weather and food con—
ditions." ht Ann Arbor arrival dates have been recorded as
early as February 20 (Wood, 1951:440—442). Throughout the
course of many years, the average arriVal date is around the
middle of March. The present uriter found the arrival date
at East Lansing to be March 15 in 1951 and March 1: in 1952.
At Alma, which is located 50 miles north of East Lansing, the
arrival date was March 14 in 1953.

The first arrivals of grackles consisted of smell flocks

(8 to 9) of males at East Lansing. There were no females

 

 

 

’W
/
~.’

until a week later. Petersen and Young (1950:466) found
the same to be true at Madison, Wisconsin, during three
seasons. While it is the general rule for males to arrive
first, the writer observed an exception to this. Two fe—
males were among a flock of nine first noted arrivals at
Alma on March 14 in 1955.

The duration of spring migration of grackles can be
determined by noting the relative abundance of these birds
at a given place throughout the migration season. This 81-
so applies to fall migration. TWO writers have reported
observations of this type in two localities over a period
of years. Jones (1895:121, 256) resorted changes in the pop-
ulation during Spring and fall for a five-year period at
Grinnell, Iowa. This locality is about 90 air-line miles
west of the Mississippi River. Trautmen (1940:141) de-
scribed in more detail the changes in the grackle popula-
tion throughout the entire year at Buckeye Lake, Ohio.

Fig. 5 depicts the averade abundance as described by the
authors in such terms as "light," "heavy," and ”same inten-
sity" (Jones) or as "fairly abundant," ”maximum abundance,"
and "few" (Trautman). It will be noticed that spring mi-
gration at Grinnell began about one week later than at Buck-
eye Lake and also the; the maximum abundance at Grinell was
about two weeks later. There is no appreciable difference

in the fall migration pattern.

 

 

 

 

 

J F M A M J J A S O N D

Fig. 5. Comparison of effects of migration on rela—
tive abundance of bronzed grackles throughout a year at two
locations. A. The average for a five-vear oeriod at Grin-
nell, Iowa (Jones, 1395). The blackened portion is based on
the resorted abundance. B. The average for a few years at
Buckeye Lake, Ohio (Trautman, 1940).

Fall

After a two-month period required for rearing their
young, bronzed Jrackles move aPout in small family ,rouns.
During this post—nesting time they pass throuéh a molt. To-
ward the end of the nolting eeriod flookin; begins. This
activity marks the beginning of a general but gradual move-
ment to distant places.

Fall migration becomes evident when the local porvla—
tions commence to slow an increase in numbers (Fig. 5). Ry
mid—August éraokles on the northern treediny arounds in Can-

) V

ada begin to move southward. The effect of this influx be-

50
came evident at Grinnell in late August and earlv September,
while the averade beginnin; of fall migration at duckeye Lake
was only slightlv later. The duration of migration was about
the same for both places, ending by middle or late November.

While there is a scarcity of late departure reports in
the literature, there are enouéh to delineate the southward
movement of the rear guard of migrants in a deneral wav.

The avera3e departure time in southern Canada and northern
United States is mid-October. In the central states it aver~
ages from the last week of October to the first week of No—
vember. By late November all of tee migrating grackles have
reached their winter range.

How do grsckles distribute themselves after thev reach
-the winter range? According to Perkins (1952:90), who re-
ported on the recoveries of 55 bronzed grackles banded at
12 stations in Indiana, grackles are at first (November)
fairly close to the Mississippi, but become widely distrib-

uted duriné the remainder of the winter. He noted that all

P.

of the grackle recoveries west of the lississ ppi were ex-
tremely close to it.

Where do Michigan grackles go for the winter? The
writer has compiled the recoveries of 52 bronzed grackles,
22 of which are from the unpublished bird-banding records at
Michigan State College, and 50 from the landing files of

Mr. C. C. Ludwig, who banded grackles at Lansing and at

Lake Odessa, which is located about 55 miles west of Lansing.

 

 

Sl

The locality of each recovery is plotted on the map in Fig. a
and the data are summarized by states and seasons in Table I.
These data reveal t-z 'nrnrsot r; "*fsts about the :ignation
and the wintering grounds of Michigan qrarkles.

(1) Almost all of the recoveries were from states loca-
ted in a southwesterly direction from East Lansing. The
states from which recoveries were reported include Alabama,
Arkansas, Illinois, Indiana, Kentucky, Louisiana, Mississip-
pi, Ohio, Tennessee, and Texas. This list compares qu te
closely with Perkins' report cn Indiana recoveries. Theeax-
ceptions are as follows: one Indiana grackle was recovered
in Iowa and none were recovered in Ohio or Betas.

(2) Michigan grackles reported north of Tennessee (with
two exceptions) were either Spring niurants, i.e., recovered
during March and April, or fall migrants, i.e., recovered
before November 50. One drackle apparently wintered it south-
western Ohio and a second was recovered during the summer in
north-central Ohio.

(5) Seven of the 10 grackles found west of the Missis—
sippi River were located Within a few miles of the river,
while the other three were located near the Red River, a
tributary of the Mississippi. This also is in agreement
With what Perkins reported in 195?.

(4) Most of the recoveries (28 of the 52) were from
Mississippi and Tennessee. Perkins listed 25 of 55 recov-

eries from Mississippi and Tennessee.

 

 

 

 

      

w

  

    
     
 

/

 

/
4

/
”In” W. 1 , f j:
/! . _

 

 

 

 

 

wu_
_ r: -

(5) The distance traveled ly grackles from Jic“i¢an to
the points of recovery varied from 125 to 833 air-line miles.
Ihe most distant reports were from Texas and Louisiana.

(6) One grackle was recovered in Mississippi on May 23,
nearly a month after migration ceased in Michigan. Perhaps

that bird had been injured and was unable to fly north with

the others. It was reported killed.

 

 

THE NESTING CYCLE
Introduction

The study of the nesting cycle was begun harch 29, 1951,
at a small (seVen acre) marsh, composed predominantly of
meadowsweet (égirgga Elba) and reed—canary grass (Ehalaris
arundinacea), located just beyond the southwestern boundary
of the city limits of East lensing (T4N REM SE4 Inghsm Coun—
ty). Since this marsh is located near the Trowbridge rail—
road signal tower, it will be referred to as Trowbridge
harsh. Because obserVations were begun nearly two weeks
after the first grackles arrived, their activities on arrival
were necessarily omitted the first year. luter (april 9 to
June I), however, obserVations were made almost duily. A
total of 14 pairs nested here that season. Egg laying, incu-

bation, and hatching were carefully followed and growth of

\

the young was measured. Observations on parental care were
made from a blind. n map((Fig. 7) shows the vegetation zones
and the locations of the grackle nests. Tests were collected
and examined after the young had fledged.

Investigation of the nesting cycle was resumed on Larch
10, 1952. Daily checks were made on the campus of hichigtn
State College and at Trowbridge harsh for early arrivals of

bronzed grackles. The arrival, courtship, and the early

 

 

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mm>>oe 20‘ L. <> k ammo

 

UMDFWSA

 

 

 

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—_—-_p—-.
0 fl"......-
.q

. ¢ .

cugok x m uuoiu‘Somh 1m

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0731:! N803

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36

phases of nest building Were followed at a colony nesting i.

m

ruces and Lines loc ted on the campus. Cbserv'tions at
this ilace were made frwm the ground only. hests Were not
measured or examined since the lirds had chosan to nest near
a dormitory for women. The location of U is nesting area
will be referred to as Williams Dorm. at the marsh the en-
tire nesting cycle was studied from larch 10 until June 5.
Measurements of growth were not taken at the marsh tilt sea—
son.

During the 1952 nesting season measurements of growth
of nestling grackles were taken at two other localities.
Une colony was nesting in a me dowsweet area, which was about
one acre in extent and was crossed by a road. Later; 53 to
45 centimeters deep, was {resent throughout the nesting
serson. This bushy area, locwted along Forest Road near the
southeast boundary of the city limits of Lansing (T4N Ray
526 Ingham County), will be referred to as the Forest Road
colony. The period of observations Was from key 3 to key 50.
The nest history was followed for all nests tut one. This
one contained eggs which were being incubated at the time of
the last observation. The other colony was situated among
black willows (Salix nigra) which were screened on all sides
by a willow thicket. This nesting site was on the northeast—
ern edge of an extensive SWamp (about 80 acres). The willows
were in water 50 to 55 centimeters deep. This colony, locat—

ed near Collins Road, six-tenths of a mile south of Forest

 

37
Road (T4N RBW 325 Ingham County), will be referred to es the
Collins Rosd colony. The ,eriod of observations, including
measuremen s, was from key 9 to hay 30.
In connection with a study of the gopuletion density of
bronzed grackles in the East Lansing area during the nesting
season, a systematic search for nes s was conducted over a

lz-squnre-mile area. Nearly all of the ne"tins itesxtere

)

0
{0

spotted from an automobile. “ll of the llaces which could
not be eXamined in this manner, such as woodlots, bottomland
woods along the river, end the more distant areas from the
TOdd, were investigated on foot. Phis study covered the ,er—

iod from upril 25 to key 15.
General ecological Considerations

Physi “rgghy. The topographic features of lichigur
were formed, for the most pert, by the retreating ice of the
last ffiisconsin) glscisl eyoch. m mantle of glacial till of
varying thickness WHS laid over this blecieted surfece by
the retreating ice. As the ice melted and retreated, such
surface feutures cs moraines, till plains, kemes, and eskers
were formed during the close of the glacial epoch. Due to
Door drainage extensive areas of melt water accumulated,
forming lakes, some of which subsequently drained and left

flat lake—bottom land, another important topographic feature

in MiChigan.

 

as e3.

1 4.0

 

58

at East Lansing and the area to the south of it, where
this study of the nesting cycle was conducted, the togogra-
thy is level to gently rolling. a moraine exterds in an
east-west direction along the south limits of Lansing and
East Lansing. It may be identified as a complex system of
low hills or ridges with many foorly drained hollows among
them. Some of these hollows contain water the year around,
creating small marshes or willow finickets, e.g., Trowbridge
harsh and the nesting area near Forest Road. To the north
and south of miis moraine there is a gently rolling to level
till plain. The Red Cedar River flows westWard along the
northern boundary of this area to Lansing where it is conflu-

ent with Grand River.

Climate and weather. Seeley (19l7z35), who made a study
of the climate in Michigan based on 50 years of weather data,
described the climate as follows:

On the whole the climate of Nichig n is not extreme in
temgerature, either in summer or winter, the rainfall is
sufficient for most crols, the cloudiness is greater in
the winter and less ir the summer than in regions remote
from the Great Lakes; nae humidity is rather high
throughout the year, especially on the lake shores; the
prevailing winds are westerly often high on the lakes
but decreasing as they FHSS inland. Severe local ghen-
<3mena such as hail, tornaioes, torrential rains, etc.,
occur infrequently.

at East Lansing the first signs of spring appear as
early as late February or early March in protected places
which are eXposed to the sun. However, spring does not be-

come established until mid-March within the city and not un-

 

 

 

 

 

39
til later in the DLGn countryside. This is the sauson of
high winds, cloudiness, and ten; ratures hovering around

A0

freezing. At night tie temperature is usually telau 3: F.
and during the day may rise to 50°or 60°F. These conditions
remain about the same during the early part of the n sting
season, that is, until the second or third week of “gril.

By this time the temperature at night is only occasionally
below freezing, and during the day it may be as high as 80°F.
The month of May and early June are definitely Warmer, rang-
ing from 40° to 55°F. at night and 60° to 85°F. during the day.

A summary of weather conditions for the months when the nest-

ing cycle Was studied at East Lansing is given in Tarle II.

Biotic community.‘ Lichigan lies within two biotic com-
munities, viz., the Deciduous Forest in the southern h'lf of
the Lower Peninsula and the Coniferous-Deciduous Forest Eco-
tone in the remaining portion of the state. The original
forests have been modified to a great extent by cleorirg and
draining the land for agricultural purycses, esgeciull:
the lower half of U'e Lower Peninsula, a-d ry lumberin- and
later by forest fires in the upper half of the Lower lenin-
sula and the Upper leninsula.

The original deciduous forest of the East Lansing area
Was composed of three main tyres or associations. Cn higher
and drier ridges there was an Oak-Hickory Association com-
posed of 3uercus rubra, 3. ELEE: and Hicorig ovate. The

remainder of the area was a Beech-Maple association except

 

 

in the very low end wet places. It was composed of E-';,

Emericana and ncer sacchurum w’t; consocies cf Tilia uneri»

 

 

 

 

:ena and Fraxinus emericana. Along the dad Cedar River and
-ts tributaries, where there were flood plains, a bottomlond

?orest consisting hf Ulmus americana, Acer rubrum, g. sac-

 

 

 

:harinum and Celtis occidentalis existed.

 

at present the original deciduous forest has been re-
luced to small patches of woodlots, shade trees both in the
3ity and around farm dwellings, and hottomland woods along
»he river. About half of the area under study was urban or
suburban, while the other half was farm land of which about

.0 per cent was wooded.

General habitat of Trowbridge Marsh. Trowbridse Marsh,
1 poorly drained hollow in a noreine, was probably a smell
.ake at one time (Fig. 7). It has been partly filled, chief—
.y by the products of vegetation and, to u lesser degree, by
lluvial degosits from the drainage slcyes bordering it.
luring the course of time a considerable deposit of peat ac-
:umulated in this marsh. nt present rost of the area is cov-
ered with rater during the period from October to Lay. The
'ater level, however, lowers during the dry season, so that
n normal years water stands in three of the five degree—
ions, or, in excegtionally dry years, remains in only one.

Man, too, has slayed a part in bringing about the pres-
nt condition of the marsh. Two railroads were built along

he north margin of it. ln dry seasons fires that were

41

‘I
u '-

erted by yarns from locomotives burned the dried heat on

U)

e north and west sides o: the marsh, forming the depres-
one now present in those Lluces. At one time the marsh
s drained by a ditch dug alone a northeast-southwest line.
parently the water level was lowered enough to germit elus

bsequent flooding killed

C

d willows to grow there, but s
e trees and they have since been reduced to stubs. ht the
he of this study a few black willows grew along the mar-

n and in the drier portions of the marsh. Drainage by the
tch was no longer effective. A pasture bordered the east
de of the marsh, where Cattle mere allowed to graze in

te spring and in summer. They were also allowed to enter
3 marsh yroger during the nesting season of the second

er. To the south and west of the marsh there were culti-
ted fields. A cornfield adjacent to the west side of the
rshiwes a feeding ground for blackbirds.

Viewed from a tower, the marsh was easily divisible into
Tferent vegetation zones according to the most consbicuous
Ants. Closer insgection of these zones revealed the gree-
:e of at least one or two tvges of glonts w.ich were abun-
Lt enough to yroduce the upbearance geculior to it. This

the basis for determining the name of all but one of the

eggearing on the mo, (Fig. 7). one Vegetation zone was

U)

Le
:ed on the basis of the common occurrence of an inconsgic-
[S bog-rush (Juncus tenuis). Five vegetation zones were

mitified as follows: (1) Juncus tennis zone, (2) Phalaris

 

 

W
L;

. I" "W I 1". 1“
J:LJM;ZlC;-

f. ;- ‘, _ ,,‘ in] r ,_ '.. ,- -" 5;
he, (a) ahirueu zohe, la; P*.hn zone Lu (u

 

s zone.
of all the vegetation zones studied in this no sh the

nous tenuis zone had the host complex mixture of lants.

.
.n

 

re—

Cf‘
C?

was a zone of transition, lying between tne moi:
ving :lunts cf the marsh wnd the ,lnnts of the drier old
eld (Plate 1, Fig. B). This zone groved to be an inlortsnt

irce of nesting meteriuls; such giants as (guhcus tennis)

1 (“selenias incarnate) were used. Tie giants comronly

 

1nd in this zone ire recorded in List I.

There EJS q nearly {ure stand of reed-osnary grass in
3 Phalsris zone (3lete 1, Fig. B). This srass was an
portunt material used in the coarser structure of the nest
Egrackles.

The Soiree; 7ore, named lecruse of the ntundULce of
:dowsweet, was the most conspicuous zone (Flute g, ig. n).
the e r1; geit of the breedirg season the 5;irhes hushes
aw in veryfira CCLdltiurS of moisture--from don; ylaces to

4. 3

;er 40 to 50 cert_hsters deeg. 3 second shrub, n willow

J

grec'lig}, was ,reseho, Ltt rot ~lundnnt. among the

H.
>4

: l

 

Wreen bushes in the yetter nieces there was reed-con r

53, which was about two-thirds the height of the rushes.

‘J

E; combination of ‘Lirse bush and reed-cnrrry srgss was

(
m

 

grackles' favorite chciee for nestirfl sites.
The Tvphe zone, CCIDIiIUELz-C of comrrm catteil (Tygha lati-

:ia), was found in nearly Lure stands. It nos irvsded

 

 

 

45
.ong the moraine lg sxxue of the grassim?=mui :rrowho d (be —

.orig sy.). This vee

Lfln Lion pcnwe w.45 usex. by time red-vqugs

h.

my sites but not by the or ckles.

\J

M

nest

V

“‘3

The Calamegrosgis zone was a y nssy pres com;osed chief-

 

of reed-bent grass (Columngrostjs neglectg). It was a
at tree in sprirg but was one of the first shoes to become
'y later in the season. giants found in this zone are re-
:rded in list I.

u considerslle portion of the Marsh was bordered by en
.d field.<xmmnuhity. thyme of tflmexcecd stellx21isec ly the
Tackles in their nests came from this zone.

The variety of Vegetation zones at Trowhridge Larsh
‘forded many niches for nesting sites. The writer noted
:sts of several species durirg the course of this study,
it no Special effort was Made to survey the pasting goguln-
.on. Cornell (1950), however, included a survey of this

his investigctioh of the vertebrate herniation of the

‘
-

:rsh. The combined list of hiros observed nestirg in tie

s—J

:rsh yroler or in the adjoining fields is records

1-‘0
F.
{.2
C"
F)
CD

In addition to breedirg, birds resident to the est

t1]

:nsing area used the mnrsl for feeding, resting and/or for
aostirg, while others merely flew over it. Early in the
astihg season transient birds vlso need the marsh in the
ime way. A complete list of resident and transient birds
:ich were observed at the marsh during the course of this

.udy is recorded in Table III.

 

44
Not all birds were eccegted in tiis marsh community
Lttiout Protest from the grechles us well es from the red—

Lrugs and hinghirds. Birds which were harassed ;hd chased

7111.6 they rested on a gaps-1", or We". .‘"()"‘ ‘-,"'_af"‘- 3;;- f.

L'}
I o

:ilgt
rueri'en tittern (only while it was flying low over the hush
ages), Cooper's hawk, red-shouldered hawk, osprey, sora
only when it was within 10 feet of a nes ), and gruelitznn
ITWV (if it flew at an altitude of about EC feet or less
ven? the marsh). {ingbirds aided grechles aLd red-wings in
freeing the Cooler's hawk, which, the writer believes, raided
1M3 grachles' nests several times durizg the two seasons.
.ed-wings end gracnles were the irlv birds U at chssed the
iflMars mentioned in this list.

Mammals observed there by the writer or by Cornell com-
;rise List II. Dogs also frequented the marsh, being attrac-
;ed there by the ,heessnts, eshecially in the early tart of

;he seeson when the theasents were still usi.g the marsh for

‘h

a roost end shelter.

Reptiles were not common. only one sleci

 

was observed, a small garter snake, Thamnoghis s. sirtaiis.

 

 

Three sgecies of turtles were found: a snao;i
ghelydre sertentira, two painted turtles, Chrvsenvs 'ictw

....—~ A!" i

narginata, and one Blending's turtle, Boys tlahdingii.

 

Two kinds of fish were found in the marsh: western mud-

minnow, umbra limi, end brook sticklebeck, Euca‘le incon-

I
*
v..-

 

 

stans.

 

 

 

45

hating

In two seasons of study of the rating of hrohzed firsck—
33, little more then a foundation has laid for s more thor—

\

ugh study. There are several re sons for this: (l) a late

0

tart the first sesson (the study W38 not begun urtil after

1e females had arrived); (a) wide~rehge habits of the gr ck-

(N5

es-—their ectiVities are not confined to a limited territory
ithin.the colony; and (3) unmarked birds (an attempt w.s

ads to trap them st Trowhridge La‘sh the secord year, but
ithout success, end tended young did not return to the
ersh).

In shite of these shortcomings and difficulties the
riter was able to establish, in J general way, some features
f the method of geir.formetion, courtship, and also the notes
nd displays used st this time. 3y olservihg their activities
rom day to day, Specially durirg the mornirg hours from SUh-
ise until l0:30, the observer we; able to distinguish certeir
Ldividuals by their voice ch racteristics, attachment to
ertsin trees and bushes, or by the actions of males toward
emeles.

Arrival gt the breeding grounds. he stated earlier,

Leles arrive at the breeding grounds first. On larch 15,
.952, two resident males were observed at williams Dorm.
This number had Encressed to five by Nurch 21, die date of

:he arrivel of die first femsles. all of the males associ—

 

 

 

46

ed uith this colohy (la to 14) had arrived hy March a7.
n eXect count of the mules would he almost imgossihle he-
use of their constant movirg shout and the obstruction of
e View by trees.) hot ;11 of the males arrived at the
ne time; some arrived after the first ferrules. l‘rohzahly
3 arriVel uf the m les is spread out ‘ver e geriod of two
eke.

This same year two females were first seen at Williams
rm on March 21, six days after the arrival of the first
.eQ The number of females gradually increased to l? by

La.

:ch 31; this was the total female tOpuletion of this col-

Territory. Bronzed grackles do not have 3 strong tend-

 

57 toverd territorielism; if any, it is the territory of
pe Ifl' (Nice, 1941), i.e., restricted to a smell area (10
5%) feet ) around the nest. During the first few weeks of

(seson mules spend most of their time comyetirg with other

(0

W
I

as :for a female. Such activity is :ot imiteu to the ter-
>rgr estsblished by the male, as is the case with many other

ls; .nor is it restricted to the resting area of the colony,

t znsy occur within a radius of e half mile or more.

p.

1“the heirs are formed, the males guard their mates egsihst
51t136ntiODS of other males on and off territory-~1ike
31"5 tdackbird (Williams, 1952:13). From the time of the

blgiskmmmt of the nest the male stands guard on one or more

 

shes located from 10 to 50 feet from the nest. uhole tn-
er.male gr cklt alight on one of hi: perihe: close ,n the
t (15 to b0 feet), he will ceuse the intruder to leuve by
of two ways: (1) by flring to a _oint beside the intruder
performing his display and srng, or, (X) by perching be-
e hin and pointing his bill toward the sky and side—ster-
Lg rigidly toward him. If after these performances the in—
lder has not left, the defending mule may fly to another
?ch, only to return after a few moments to retest the in»
nidating acts. This usually ’s effective and the intruder
ives quietly. Fights or chases were not observed to take
ace under such circumstances. This act of guarding, how-
er, usually takes glace when the female is present or on
e nest. At this stage of the nesting cycle he is guurding
e female and not necessarily the territory. Later in the
eeding _§‘-eriod, when there ere ymng in the rest, the mzle
twins on guard some of the time while file femele is away,
t it is not uncummon to find both of them away for periods
long as 15 minutes. Territorialism, then, arrears to be

ndted to an indefinite area around the nest and around the

nmle wherever she may be.

kind of mating relationshig. honogany is the most com-
Ihldrd of mating relationshig among birds. n monogamous
‘mwticn usually exists where the sex ratio is nearly even.

YWH‘(1937), after sexing 204 bronzed grsckles which he

 

 

 

 

 

48
dered to he a fair 8 nrling, fourd the ratio to he 48.5

NJ

ent males to 51.5 yer cent females. Inasmuch as six or

of the males had been removed from this samgle before
ceived it, the actual ratio would have been nearly 50:50.
At Trowbridge harsh and at Uilliams Dorm the sex ratio
ound to be nearly even, and from observations it appeared
monogamy yrevailed among these birds. It is true that
g the early stages of pair formation, when two to four

are courting a single female, it is difficult to ascer-
whether a monogamous state is going to preVPil. Later,
er, after pair formation is completed and nesting is

way, monogamy is evident.

§9_n_g_dis}.lay.~ As far as the hunan ear is concerned, it
yesticnable as to whether the vocal sounds made by greck—
hould be called a song. How would one define a bird's
Mrs. Nice (1945:144) uses hicholscn's (lgtgz4l) defini-
with the addition of the word "sometimes” as follows:
flrd song is properly a sustained, more or less uninter—
'upted repetition of one or more notes conforming recog-
isably to a constant specific type and [sometimes] used
W the male as an expression of independent sovereignty.
ding to this modified definition, the grackle's utter-
would be classed as a song. Their song has been des—
ed by several authors. Audubon (18k7—1850:7) used such
:tives as "squeaky" and "creaky" to describe the call, a

'ication of U16 song. Forbush (19a7z455) said the

49
. . . song of a flock has been compared to creaking of
swinging signs, rusty hinges of iron rates and creaking
3f unyoiled wheelbarrow or cart wheels.
rs. Nice (1951:171) the song sounded like a ”whicher—
." Saunders (1951:254) had this to Say about the grach-
song, although he did not specify that it was the song
is bronzed grackle:
It consists of one or two short notes followed by a more
prolonged squawk. The quality is harsh and squawhy or
squeaky, with a peculiar metallic sound. . . . It sug-
gests a rusty hinge or machinery badly in need of oiling.
The present writer also observed thit the song consist-
f two parts: (1) a brief double syllable corr spending
he "wicher" part described by Rice, and (a) a longer part
h is the squeaky portion of the song. He further noted
the male's song varied among individuals in both qual—
and intensity. This became apparent when three or four
:s, which were perched near each other, sang and displayed
;he same time. hereover, while the song L35 basically
same for all puryoses, each individ‘al male varied his
according to the use he made of it; for example, a
,le call to a mate was weaker than the courtship song.
The display which always accompanies the song is so
ad that it begins ahead of the song and ends after it.
general, the diSplay movements consist of raising the
3hers around the neck and spreading the wings and tail,
ing the bird appear larger. The following description is

ad on a single courtship song display observed on harch El

50
atflflliams Dorm. It may be broken down into five stages:
(l)diqlay movements began by a fanning of the tail feath-
as;(2) before the tail was completely expanded the wings

mnedslightly upward and outWard; they were relaxed and

simultanecusly with the win

0Q

hmkmisomewhat drooped; (3)
nmvmwnts, the feathers about the neck and shoulders were

raium and the neck Was arched; (4) the first part of the

song was uttered with the outWard movement of the wings and
a ruffling of the neck feathers; (5) as the wirgs and neck
feathers returned to the originzl position, the second part
of the song was produced and coleeted before the displsy

movements were finished. The frequency of the song of this

male during courtship was 10 to 12 times per minute.

The female‘s song disgley is given in the same manner

and is about as well performed as that of the male. It is
11sed-i11 restohse to he ccurtshi; dis;lay of a sale but more
often] as a call or a resgonse to a call from her mate. nc—

COITLing to Nice (1943:132),

of self expression, or as

and particularly where

inir, it may be equally

lfliere song serves as a means
ari eeression of a social bond,
i1: serves as a bond between the
((Dr fairly equally) develoged in both sexes.

518 .femnale's sor or call sounds much like thqt of the male

15
1t 5-3 enough different to be distinguishable in most CLSBS.

3: tc>c>, is made up of two parts. The first i.art is the s1me

t11s:t of a male, that is, a double syllable "wicher." The

a lower pitch than

‘cond part often ends at o ‘1 t of the

vii.)

.‘l
' ‘3 "- - ' - “ ~- . ~ - m A --- a .- ---: - '
‘4=- othetimes the idyllt} is for; of a bus than a eases“.

 

i
i

 

'3: J 1‘. .. . .4 a L . .1 .sii' 4 ‘_ '- _ i '
.1- L _ tir . iii ;.,1 . - h - v', i J

LC , pr. . s . L .

we 4 '9

I , ‘ in. J. 7.J1 .4 .a ' \r’ -4.J “ 5 ,J. L 4. J- ‘11.:-d
- _, (A J11§ AI, in: , L... _ --‘ a? . t' . V 7L, a i- "
e.- . , s3r,rt.; idgil arul legs :iridenvianc:.
Lees of the song_disblay. By modifying the song dis-

 

 

Xie male uses it for several atuarent ,urgoses.

L) Challenge. In the presence of one or more other

he sings and disgluys in Ccmyetitior. This is evidenced
more exaggerated buffing of the feathers end extending
e wings, along with an increased frequency of song tnd
ay. a female may or may not be gresent.

a) Courting. The song display of a male courting a

.e prior to coyulation is the most exaggerated. It may
3rformed on a perch or on the ground. luffing, arching
neck, strutting, and performing the song disglay very
dly are characteristic.

NH 335;. .n mated gulf uses due song disglay in its
:estfkrn to call to each other. For exumgle, then s isle
lrnstm his gerch near the nest, he Cells to his mate, and

letbnfrestonds with a similar call.

Cmutshis flight of mile. One of the most character

‘Jo

S-
nmrksLfi a male grickle in the spring is his display

~.A

ght. hlits extreme form it is a slow even flight made

 

 

52

.ea‘by a deetly heeled toil und rugidly fluttering

1&3 uses this flight around the nesting urea, flying
frown perch to perch, or following his mate while she
strurfidng the nest. 'Itzncslower Umnilre:cruisihg

of tlmafemale and is, therefore, modified for fester
by tdie use of s less fluttery tyre of wing beat ind a
,ly less ”V—ed" tail. Bxcegt on the longer flights,
is to and from the roost, the tail is heeled most of
une during the breeding sesson, even when the bird is
perch or on the nround. With the tail in such a form
ird looks longer. us the breeding season advances, males
ally change the diSpluy flight to s more normnl flight
the tail heeled less prominently erd 138$ frequently.
imes they may be seen leaving a perch nith the tail un—
:d and then suddenly depressing the central tail feathers
>rm a "V." Unce when a male wgs returning to the nest
food, he was seen to be flying with his tail flat, but
W'it as he neared the oerch close to the nest. This

:flmerved as late in the season as May 31.

Ikumntion of Hairs. Comtetition for females begins as

 

.as1flm first females arrive. Two to four males may be
Lflyhg with or perched near a female much of the time
i nmfi3building and less frequently throughout the egg-
Lnggxmiod. In such a group there is constant rivalry
1gtmenmles, as indiCated by intimidation displays--

chdflenge song and bill-pointing. The latter emphasizes

 

 

53
(Dr lieight of the bird ratler than large size. It is
-isflied by the bird's assuming a rather rigid pose with
3k.exxtended and the bill yointed Skyward. Comgression
lmody and neck feathers causes the bird to appear slim-
<i taller. It is usually a very effective means of in-
tiju; the other tird, especially if the latter is near
cmner's mate. "bill-pointing” is not Carried out as a
project among males, as it is among boat-tailed grack-
iassidix mexicanus major, which stand on the ground or
in a group, all-tointing their bills ugward at the same
(McIllheny, 1937:276)

Group courting on most any suitable perch and in flight
conspicuous activity which is characteristic around 3
.ng area in the early gart of the breeding season. At
.ams Dorm, where there were Norway spruces-zO to a4 meters
and a few nustrian pines l: to 15 meters tell, it was a
:nisight to see such courting activity most of the time.
arQLZS, at which time there were only two females and
24nmles present, a tygical courting scene Was noted in
:fl.between 10:00 and 10:30 “gm. Four males and one female
:perdmfl on the ridge of the roof of the dorm. all of
rmfleswere singing and dis; aying with much gusto. The
fie mxmonded, now and then, with the call song, but, in
smal,she Was not too concerned. The songs of the indi-
tmlrmdes ranged from an immature one to the typical song

m1byvmtt was considered to be a mature voice. The dis-

54

all. was stimulated, but more so in the case of the
n tflie immature voice. He puffed out his feathers
d eyxtonded his wings farther than the others. One

ot; the immature~voiced one) flew to another yoint on
d’2ridge; the others followed and perched about 10
:qgurt. One "bill-pointed,” but was ignored by the
. Iie retested it with the same lack of response from
iers. In the meantime U78 female flew to a fine at
as of the roof. Then she hopfed down to the eaves,

up a twig from the eaves, played with it in-her bill
en dropped it. She flew up over the roof and away with
~ur males in tursuit. There was much chatter among the
as they flew. One was observed to strike at another
l-air as they flew from sight. Four or five other males
were present in the area during this activity showed
terest. In this groun Courtship disllay nus used to
idate the other males, not the female. The flight was
f’following the fennle, not chasing her. It agpeared

an elhnination contest.

Iaterin.the same day, what appeared to be an elimina-
cfi‘onecf’the males from a courting group, at least ten-
fily,vms observed at Uilliams Dorm. at 5:51 E.h. a
Le gmmkle followed by three males flew toward ale south—
outof View. There was much commotion and fighting
gthenmles as they flew, similar to what was observed

ier hithe day. Nine minutes later a female followed by

 

we Ifleturned from the south. had one of the three
eoome discouraged and drop: ed out of the cont-e st

:58 {N18 Cannot be sure that it was the same female,
I18 Wigs not her rhed, but it sounded and looked like the
TJUP 'that rumi<iewgrted only a fwwvrmhmites before.

Kfily courtship flights were occasiohally Observed at
net IQCatel at CO)lidw,e Road one and one~half miles

est.<3f \uillianr:1)orm. .Antzegxiisxzsfimong tnhe mel¢N3 at

ime appeared to be less intense than earlier in the da‘,

(0
O
O
:3
Q,
P-
m
e
“C“
(D
C.
*1
kl

d after they joined the flock near the

Such group courtship flights end I,erch activities as
were observed as late.as upril 14, 195; at the dorm,

pril 28, l95l and April;33,195h at Troworidge Ne rsh.

(z:
c+

Thus, pair formation amona bronzed r*reckles at Ea
ng appears to be the result of an elimination C)n est
;'mm>to four males for a sinql e fe uznle. Intimidation
>ng§nm. Misb ay and, to i lesser extent, by bill-pointing
achithe.eerch, and by the use f niises of check :3 and
terhmgalong with body contact while in flight appear to
hermnms 1y which the more dominant males eliminate the
rdhume. It is assumed that the dcmfljnurt:nale wins the

:. Fummer inves his rmtia on this point needs to be carried

muthnwrked birds in order to establish the relationships

1 certainty.

 

 

56

v: long do ,Jir rein-21.1 mated? Normally bronzed gram}:—

(I)

se curly one brood and remein mated during that tine.

1

Eyevinning of eseh season they arrive unmeted and, cue

:netkuod of Lair formation, the chances of reunion of

rvious year's mates are slight. The family unit re—

Mitsct for two to three weeks after the young fledge,

the young are dependen on their parents for food.

The Nest

'esting site. Female grsckles began hunting for a nest~

:7—

 

.te at Trowbridge Marsh on April 4, 1952, two weens of—
le first females had arrived. ht fliis stage of the

15 cycle fairs end often groups of two pairs were ob—

i rlying about the morsh from tree stub to bush, and
Lesving the marsh cowgletely for Periods vsrying from
minutes to two or three hours. The length Lf time
sWe" from the marsh Wes governed sosewhot by weether
tions. (The relationshi"

~u ‘ fi

ities will be QlSOUSSGU later.) lkmn.‘mieir return to
tarninmst of their time was Sgent, es before, fl"ing
oneixrt of the marsh to another, but slmsys in View
athelmsh tOps. Search for e nesting site began when
?emth or perhaps the pair, would suddenly fly down and
mmsramong the bushes for three or four minutes. Upon

peering, above the bushes they azouldfly to other parts

henmralend.senrch in the same manner.

 

57

Imchirrg ogntinued until the femwle seemed to be at-

:ag~ain and again to a certain hush. Even though con-

-a

’1‘

Dri heal not begun, Ute female, 3:1 in some cases t'

CMJJJi drive other tirds from the Lush. The fenjle

U)

tile intruder, but the mzle used guarding tactic

of‘ a nesting site was not alw:ys permanent. come-

a f‘emnle deserted the first syot for a more secluded
‘The latest date in 1952 when a female was olserved

Lng for a nesthwzsite was aprililV.

ll. of the £4 nests started or completed at this marsh

tl.e two years were rlaced in the very similar situU—

outlined below:

..J

-, , , . p, .- ' - w ‘ a
,) nil exceyt )ne were ,_eted in meadOWSNSGt bushes—~

.s in a willow bush (Salix gracilis). n nest located

 

1\

a former is shown in liate s, Fig. s.

a) n clump of last year's reed-Canary

\PQ
H
{J
(’3
(D
‘5.
Q;
(I)
H
:3
Lu
P"
H

wo of fine bushes-~two had none.

3) The heights of the nests above the water range’ from
» 69 centimeters.

,4J Over half of the nests were placed fairly close to
water(ndthin 3 meters).

(5) fluewater depth was from 45 to 60 centimeters at each

IMH‘demdls concerning the location of the nests at Trow—

.ge Marsh are shown in Fig. '7 and Table V1.

as
a
-

 

Three requirements entered into the selection of nesting

sites at this marsh, viz., concealment, syncing, and seclu-

sion.
For concealment the nesting bird elied uron a screen

lus a few leafy culms of

1
PC!

of many branches of ggirggg bushes
last year's ineligis, as new foliage did not ayjenr on the
bushes until near the end of nest~building time. Conceal«
nent was furthered by d'e use of Stems and leaves of this

Same species of grass in the outside structure of the nest.
iowever, because the stiff, straight branches did not afford

good cover from above, the nests were not Very well concealed

?rom aerial predators.

imie syncing of the hosts aypeared to be influenced by
the size of‘th. area and the density of the nesting popula-
ion. .rt Trovbridge harsh, where there was a relatively wide
rea sniitable for nesting sites, the graczles staced their
:yiite far a;art—-13.l meters in 1951,_Mhen 15 nesting
s vnare rresent, and :6.5 meters the following year, mien
iere ,were only six nesting hairs. By com; rison, at the
>rest;fhxnd colony, where the area among ggiraea bushes with
nests were

litatflxe nesting sites wns much smaller, the eight

11

deced.art an average Of 7.69 meters apart. In this colony

e fkmnaleaaittempted to build her nest considerably closer-~

.ree austere from another nest that already had eggs. It was

carted before it was completed. After the young had fledged

or} the {neighboring nest, the deserted nest Was reoccuyied,

 

 

59
In} eggs were laid in it. upparently, in this case,
tolerance was greater than three meters.
:irni was attained by placing the nests in bushes
\vater. More than half of the nests were situated

P

(I)

or less from open water (Fig. 7). Since the
isually deeper there than it was farther into the
they were more secluded from wading animals.

is gave the birds a greater sense of security.

building. Nests under construction in 1951 were

 

ed in the first and second stages; however, the
fourth stages wer: followed. In 195: the ,rogress
.struction of five n s‘s was observed from the ear—
'es tu comyletion.
rests were constructed entirely by the femele, while
guarded her. For a veriod of a week after the se-
the restins site, the fen-1e had only a passive
in nest building. This interest vmried, but wis
during the early and lste isrts of the day. Inter-
how: by their actions of Licking u; resting m-tericl
rm,with it. Occasionally one would carry n teriel
sting site, glay with.it Cd'gg;'m1rough some nove—

gmfifive of building, and then drop it. nCtlal con-

dhirbt begin until a week or 10 days fter the

D.)

e chosen.
:ssummtimes symbolically displayed nest construction

esmnm of their mates. a few instances of ntles iith

. o r r H - 'r r . 1 1 - v ‘\ ' f‘ ‘ I . ‘i
, hi.termel herd observed. the fiCfidh AL Lite of grass
Q FZFUUDd, \lile his 03 was getting 1‘estinb' n Lefiol

 

(D
(G
O
i—b
x-

the branch meadowsweet bush, '..hile his .-_:.te 11.8

fexat away insiecting her hosting site before tuildirg

Hrile the female is occuiied with nest building, the
guards her almost constantly. he Lerches rear the bush
his mate is fashioning a nest. He follows her in dis-
flight to the point where she collects nesting waterial.
d another male attrouch her, he ”bill-toints" and struts
e the intruder; the lat 3r usiully lv-v 5. mt ctfief
of the day, winnirflne is not engaged jjlfljst buildiLg,

>ntin es to follow her sud guard her.

.n

reeds grackles began collecting nesting m teri 1 st

re K,tmut is, about 10 minutes sf er arrivirg from the

t. .fter a yeriod of 10 to ;0 minutes of nest building,
\flfthen left the marsh to feed,.and d.en returned :gein
boutlS minutes. From tlis time until lO:OO n.K. they
:veryactive, after which time tley became less ;ctive
weretmound the marsh ares less frequently. The teriod
hwttmndveness was sometimes broken by a few females after
Dlgh. However, very little building occurred in the lute

ernoon.

 

When nest-building wctivity We: high in tie :ornirv,
males were very lusy collecting Wateri'l, t hing it to tle
te, and constructing the LeSC. An exam le of tie degree of
tivity of one female thus rusily eng~ged from 9:16 to 9:30
M. will serve to illustrate this. She was constructing
st 1, which was very close to the obserVation tower
late 3, Fig. h). Jhe w»s getting all of the rateriil in

O

e Juncus tenuis and lhalaris zones immediately to the east

 

 

the tover (llute 1, Fig. B). The nest was at the third
age of construction, i.e., the glasterins stage (described

\.

rage 65). During the course of 14 minutes she made six

C'?’

between the nest and the edge of” the PUI'S'L, av-

Ho

ind

VI
J.

U}

i)

ng 57 seconds for the time of the flight and for col-

\J

u.
d m
P.

’..Jo

t

H

I1

is material. The shortest time was 43 seconds, ard

m

a longest was 75. The time srent at the nest also <Ver Jed

seconds; the shortest time there was 30 seconds, and the
geStJVU s 8C. A oQ—seccnd rest ieriod v.s t her after

“Vire: Tine ne;*‘ busL;c;t 7th: hd iii tzw: thiiwi tiir. '\hi;:;
Ikflrale has gt the rest, her m_te culled rest of tle time

- true to; of e willow bush loc ted sheit 15 feet Lyrth of

P

. He accomruried her on nearly every trio, following

t .
trithlliis courtship flight in its extreme form. He was

ays CH1 guard and courted her while sne WJS gathering nest-

materiE-Alo

Tfiie building of the nest May be divided into four i,wrts

edging to the stage of construction as follows: (1) tint-

\

LJI sus'ehsion rocket; (L; outside; (3) glaster cup; and,

t
L

lining.

(1.) lletfcrm o sue-ensioi tocket stage. n sus ension

 

evuork wrs necessMrily constructed firs because all of
ziests were sustended to sever 1 small, upright br;nches
rue Shiraea bushes and often also to the larger stalks of
:3ris. This Was usually constructed in one of two ways:

'by weaving a few strands of nilkweed fibers (asclepias

 

irnata) from branch to branch to form a rather t,ut, web~

3 glatform upon which the coarse material for the tottom

:he nest wis laid; or, (b) by forming a rather loose locket

hosed of milkweed fibers attached to the branches gt the.

t-rim level, trus retylly outlining the shape of the en~

e nest, and glacing a lad of course material in the bottom

the gocket to form a glatform. Nilkweed fibers were use
such supporting or sustension strands ir all of tre nests.

is a tough, durable, rd flexible ruteri 1, hence s very

.table fiber for anchoring strete"'

ructure. This stage, if nit started too early in the se;~

D:

1,vns usually comtleted the first uy of he

(I)

t building.
3 range of dates for this stage use from klril 17 to £5.

(2) Outside. Coarse grasses, weedstalks, string, leaves,
ssuepeper, rags, or most any material of that tyge was used

fdm1the outer part of the nest. Such material Was added

 

 

 

63
t<> U e tlatform. Then the sides were luilt u; by we v-
‘t circunti‘U3e urrifdit brcrnflics of iiws lush. ihi among" pe
HIE ion strands of silkweed. Nestirr muteriol for this
a of“ construction was ob aired fr 3 the surroundinr
is, the Juncus EEQLlE and ih;l ris zones. tn the average

30 “three days were required for this st he of construc-

I._J

. ‘Phe extremes were one ird four days. In 951 the Gate

(0

1=> oomtletion of the outside of the rest ranged fror April

: ;s8; in 1952, from A,ril 40 to 17.

{23) Blaster CU: stase. llastering often began before

 

 

:seoord.stfi:e has comrleted. Wet, decayed vegetation with

'—

nuui was first added to the inside bottom of the nest.

(u

itateriel was usually felt~like and adherent nough so
..j neatly shaged cui—like interior was built ut from the

mun. The thickness if the u;lls of the cup was guite ir—

L, it mus thickest on the lottim and thinnest Jt the rim.
utter‘1dnz of the cu; :: su'lly ~dnr1t on inch lxflnnx die

or edge 05 the course outer m-teri 1 ;nd Yes the last to

CD

rial for this stsge of rest building

plastered. The hit
obtained from the ground ih the wet lirts of the finISh,

efly from the Phal ris zone. One to two days mere re-

 

(i)
Cf

red. The range of dates of U.e comeleti h cf this

[X
(1‘

o 58.

{\a-
{\1
d

1951 w: in 195s, from hyril

L
'0
*‘b
H
C
:3
3

if
H
P.
Fl
CJ]
C1"
/'
“.23
n

(4) Lin stone. The first strands of lining: ere worked

LA_.‘

Ho

[TO

I“.

mithe rim of the glaster cup while it was still wet. When

 

aster ”etericd_ dri xi, tfxfic teI%::firh15f:«nchcnwed tc; it.

0

he lirdrez. This tcuf

C‘!‘
(D
t‘.’
C
F'-
r C
O
’7
5
PL
H
L '0
r '.
C
OJ
('1'
h-
L-
(L
Y)
2
C
H
'r/K‘J
/.
a
c f'

Litht w- {—3 iITtEI"."k»V€T3 ".iti‘! the
ad rieces QLnu text? in e Ige.t "wxi realm :r f sjiicn. Two
wavszmie used for this fourth s age. In lSSl the

rngcd fnan hiril t? to hug>;c; in 195s, firm11g2ril L4

stlnfllding at tr: msrsh hegnn es early 5 H}?i1 12

U)
(13

3d a late 5

m
(a)

May E durirg the two sessons of study.
Int of time for constructing a single nest st from

niIe dqyg’ on the aver ge. The extremes Mere 6 he

 

ther in relation to £98. building. It mes nointed out
w... __ J:

J

1¢M:'u e interest disgleyed by fem le greckles for
estin: sites and constructirg hests Varied écccrdinfi
HHfi )f‘cieyzund Jlso.sccordinc to weather corditions.
:flfected their gCtiVitLfiiln twt days: Hi f1~nmen-
rd-dxion or ne‘elerntior; (.E a lors range effec
.onszni or retgrded uctivity, or effected a change
tilld (Bf activity to another.

Weather :henoriene: .118 iii-”"h \aird, ire Ci; itzztien,

C

, «31‘ sunshine had e noticeable effect uh their
3n} dsry to day. There was virtually no activity when
2 liiszh.uind (15 m. p. h. or mere) comhihed with

u

'y .b3?801pitetion. They were less active or more

 

fr}
r-v
_J
l
_-4
H9
”3
LL
1
)3
fl

*retic in their ;.ct;i «is :xlwsr th~ rue
mflimss. withe other hwnd activity mus higher on x‘rner
Is with less tiqfid.

Wm immmh of the nest-site-Sesrching qufitilpdui the
firing dfrmst building seem to he governed by the gen-

tnxm cfthe tergereture. From April I to ll in toth
scfl‘this study thts.vvcrege d ilgf'twtlsruturtalfinmged te-
134°an157 F. Durirg d‘is time female grechles were
rhhujfcr TNesting; sites. In 1951 the ULWUTG trend of
engcrnture began ehout Atril 20 (Fig. 8). This marked

1d of the nest-site-seurching ieriod end the beginnin

CC.

enest-building geriod. The JVBTESG temperature climbed
o w . . .

he 40 B. range uiturd into the high 60's durirg the

teriod of rest construction. In 195: the utwerd trend

temrrnxiture been: nearly a week earlier (Fig. 9).

‘4

t iJ;_nes: building also begun as e le es myril 12,
:31; sccumer than in 1951, but did not begin in egrnest

ri]. 17’, only three d»ys earlier th~n in the gre'ious
iiss slcnw startrmsy he uCUQHfitGd for by the fact thst
'd 'trwuid in temyereture levels of? in the low 60's,

rthLLLt, tic rest-building t,eriod u s irolcngee to

-.£'-I‘il 1.; tc BC).

SISIWICTHJIS. Six nests were remcved from Trowtridge

 

eexual;ysxis. The average dirensicns were as follows:

Diameter Del-tn

Cm. In. gm. In.
Outside 16.48 6 g2; 13.45 5 3/8
Inside 9.98 3 7/8 7.60 3

 

 

 

 

 

 

 

 

 

 

lb 14 16 18 L0 La b4 26 28 5O 2
l l

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

34— I I l l I l 1 1 1 184
32- _ g
30- \ -80
7e \\ 138
76" 1 I
74- -7.
72p _72
70- ‘70
68)- “'68
66- / ~66
64' . ~64
62- ~/ 162
60' / -6O
58- / 458
56- \ / 1 -56
54- ,. / 154
54- I’S§§5F§n 52
23" ~ 1 \\ 1 fig
46: LL (Sfifl :46
42- 16% j _42
40". b// l \\ ll -40
38-.nfl_.._myflflp I \v *3
36 \ xx I -136
P \ 6 \ I \ .-
SOL \——-/ \I J -30
38 I ‘V' “238
36‘ -36
L1 1 1 1 1 1 1 .1 1 1 1
18 l4 16 18 20 as 34 :6 £8 50 2
April hay

Fig. 8. haximum and minimum temper-
‘es during nest building at Trowbridge
sh, 1951. Solid line shows maximum tem-
1ture changes, broken line shows minimun
1ersture changes, bars show range of dates
leach stage of nest building was complet-
unshaded portion is interpolated). The
ges are as follows: (1) nest started;
platform; (5) plaster cup; (4) outside;
lining. Trend drawn in by eye. (Weather
1from Station Meteorological Summary for
fing, Michigan, U.S.Department of Com—
38, Weather bureau.)

 

 

 

 

 

 

 

 

 

 

 

D
)
5
)
1‘
3
3 32- , -Ss
3, so . , -30
3 261 see
1 26- -26

 

 

I l l l 1 1 ‘1 _1 1 1 1 I ‘1
12 14 16 18 so it 34 s6 be 30 z
upril May

 

Fig. 9. Maximum and minimum temper—
atures during nest building at Trowbridge
harsh, 1952. Solid line shows maximum
:emperature changes, broken line shows
range of dates when each stage of nest
auilding was completed. The stages are
as follows: (1) nest started; (2) plat-
?orm; (3) plaster cup; (4) outside; (5)
Lining. Trend drawn in by eye.

{Weather data from Station Meteorological
Summary for Lansing, Michigan, U.S.Depart—
nent of Commerce, Weather Bureau.)

 

 

 

1 - ' -1 . 1 1‘
er.5e 1r; .eidht of tre six nests * s 1.L.56 7r,rs.
...' w “p ' - 1 rfin o 0‘ O {
t«11- 1 rest CJAV ‘. ‘or,os1tion ire giyen -n P Lies

V.

m

fter weighing aid men uring, esch nest was 0 refull'
tied into three parts, viz., the outside, the lining,

a plaster our. Plate 3, Fig. B shows in cross-section 1
:ese three perts of u nest.

1 general, the nests appeared bulky due to the size ch
sure of the on side structure. The walls were from

4.5 centimeters (1 to 1 3/4 in.) thick znd were izde
rse material. The outside com1rised 14.6 1er cent of
Lfiht of the nest, but it amounted to considerably more
:. All of the milkweed fiber used for the ,latforn

3er well of the nest was i clrded in the weight of the
3 material.

1e lining, which w1s 43.8 per cent Juncus tenuis stens
1e fruiting heads, we: diCVTuly enclercd about he rim
nest where these plant stems had adhered to the ,luster
7he liring of one nest, which had teen deserted with

1 it, w1s t ken gpsrt, .nd ‘he length of ewch tiece of

11 was measured. The mens'rement Jf Juncus tenuis

 

1 51.19 meters (167.3 ft.). On the basis of the number
.ting re ds present this eprssented s rts of :43 ,lants
species. This was more than five times the length of
.5terimls, such as fine grass stems, le ves, and roots

.n the lining. The average weight of the lining w;s

ight of the nest.

(D

mans or 5.9 per cent of the w

_
ll
_

 

 

 

C >
L0

 

The glistor or s ”ir' in strzcturs. Tie tii-hnvss
of the botton cvlr.f-u 1.71 Certim‘tcrs (L/e 5:.1, n.19 t} t
u? the rim 3. C.CC f“ +11: 312.11 11,141 '~;.). Th: -;1-. r
surf1ce of the “2,, his: 0.13 in cost ht vitf tL: u"t:‘de
structure of he rest, v s i“r="lur, Int the irrer :‘rf'wn
as: smooth .11 symnytric-l. The l (ter 3', of one nest,
seeked in v' er in urder'tx;<l:tcrnlnc its tnmgtm:ition, ;,s
ffiund to be con513en of EFW11 fr'5nents of roots, s,ers, and
leaves of grasses, sedfies, nd FVr—reed (JLurgsztm bury—
certum) wiich vere uita soggy when met. Internixgd .ith
these bits of lurt ” tori 1 . s a rush :rh Ber mount 3?
organic nud cont irirg fibrtus plant 5LtCT1J1, sh 11 fr ;—
ments 07 stems, le.Ves, ird roots, and f~1 snail seeds.
3 fivcrite s,nt fer collecting this x.t,rial 1.3 «t the 1 see
cf ihel,r s grounrg .lorr tre uter Tt of th> rsh. The
gl,ster on} mus the he vie;t .rtibn f the - st, 3V“? LIBK
dry, com1"isin£ 'e-rly “9.3 ,:r cent of tte total weight.

”s hertofcre stated, suggert fir tie nest: st frcwbridge

C

LI

harsh m;

bushes 3n

rests examined w

average;

halr: i

*1
m

1'.

 

I

19.

 

furnished by the m-ny tprirht st rs -f
d, in neny CGSLS, by stem: of Fielsris.
ere supporteu by 13 §1ireee steps,
the nrmber rwrged frsm E to ‘9. Trere re

C
p

on th e

C

NI

tem ,

"1 ».' .
i}10 CL).
..,. 4"- .‘_
Kli- J 'ka

Durability of the hist. The nest endures the newr of

 

1.

*1

('D
1

J...

relrirg a brood guite well. The : rts vf the nest thut
ceive the most wedr wre the rim and the lining. By the tine
the young fledge, the coarse material forninq the rim or up-
per edge of the nest becomes ires:ed down to the level of the
plaster cup. huch cf the lining becomes broken into small
fragments, tasting away into debris, which accumulates in

the plaster cup. but it does stay intact around the rin where
it is cemented to the plaster cup.

By October all of are nests are soft heceuse the mud of
the plaster cu; hes been meshed out by rain. nbcut half of
the nests are still in good shape, thile the other h'lf are
either b dly deformed end hanging by a few :trxnds of nilk-
weed fiber'cus‘they are con letely dwau liestS‘MIich had been
constructed in 1951 were exumined on k rch 15, 1958. Iinter
weather ted destroyed most of then so ccmglwtely th;t they
were not found eVen though the m rkers vere still there. The
combinetion of mind end pressure >3 snow Led torn wll but tn:
frOm their original gositions. Traces of gr ss m~rked the
Llsce of two otiers. One of the tWL, .L1;n ”ere Ht ~just: the
OTiginsl level, is . mere mass of weeds and grass, while the
Other Mes still well formed.

Apparently gruchles do not re~use their :es s. oirce
they raise but one breod, there is no further need for 2 ~
“OSt during the nes ing season. Nests w1ich have gassed

through a winter at East Lansing are usUelly not usltle the

 

 

 

next season. One nest was built on a mass of

might have been a nest of the grevious year.

('1'

Survey of nes

atic search for nesting areas of grackles was

ing oopuletion at iast Lans

r71

material which

ing. A system-

cenducted from

April 1 to Lay 15, 195;, in a la-square-mile area in the

vicinity of East Lansing (rig. 10).
vey was to determine the location and
sites and to count as accurately as L
breeding pairs.

The area
eral types of habitat.

(1) Urban

 

.. u- an.-

The purpose of this

SUT-

situation of nesting

ossible the number of

chosen for this survey consisted of three gen-

or suburhan, with its city streets, parks, cem-

eteries, residential districts, and the campus of kichigan

State College.

(a) Country, consisting of small ”city farms,” general

-‘a-..

farms with woodlots and trees around dwellin' laces, marshes
’

and swamps.

(3) Uottomland woods, some of which were within the lim—

_‘--—-‘_-. n . “-

its of the city and some in the country, but all in the flood

Plains of the Had Uedar diver and a

Locating the nesting areas

two Wave;
\l

Kl! the

D

fact that courting grackles

small tributary of it.

was greatly facilitated in

were easily

Spotted at a distance by virtue of their size, noisiness,

f

and attachment to certain places; (a) many roads that

the area studied made

° .-, ..°.-.1
it r".';:.Lx.'_Le

mu .311

cf the

 

 

 

%/

Iclj I (SAN Av .

 

 

 

/////////

KALAMAZOOjr

 

 

 

 

 

I"

 

 

  
    

 

 

 

 

 

 

 

 

 

 

 
 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

    

 

 

 

 

 

 

 

 

 

' ’// /‘V“‘&“““" ’
«‘32 ‘ u" ' ‘
HE..\§1_B_§ -- - - L
_V/ \\ \\\T§ \\§\ \ Qw;
/ a
g\\>R\E;:\§Q ' \ SIC: \\ \>\\ Q §\
23 - wee \w \\\ \\\
\§§\\\“ \\\\§§
9 \Y\ \\ i
M \’ \\\ §\ utti E‘ROAD\\\9.\\ L
r .fi 1h Ir—

 

Fig. 10.
(1)

Of discovery.
colony; (3) fi'

, ;ichigan Avenue colcpy;
(5) Forest Road colonv (5a a single

 

,
litnbeii

Trowbridge Harsh colony;

‘”‘"t
.1.)

 

of colonies in
(2) w
(4) Bennett Fern cclonv;

); (6) e

Nesting nonulation of bronzed QPlelSS in the
vicinity of East Lansing, 1952.

order

illidms Dorm

single nest;

(7) Collins iioad colony; (8) and (an) Cavanau;h Road colony;
(9) two nests; (10) Music Fnilding colony.

 

area from an eutcmobile or a bicycle. all let tn- cf the

x .0, . fi_- AN: ‘, JE'C ,,.. om, ,' ,, -,—'. . ’ .~‘
‘JC'l‘.)an-BE: v '31‘: (Si‘L t! [1&(J .Ll: J- -L; \VTA'VV a ‘1. -‘_:_ ' . -)_ ' v 1;:.-
‘ I - '- ~ - ‘t-“. . ' ' 1_- I- V. ' ~n.\‘ ’ ‘. 'u‘. -~ “q u .-

n-e L‘e tn [Lean .; Hm; L211. 3, -.1 as. . ) Hows 3 T.“ , can, - ‘.".’U',~‘.. 1 0 b aria. 13]]

list

1'.)

nt Lflxaces :diich VhéPe >A3TUCIU$U frwu. vi~av fron:?ir> road
were traVe: ed n; hiking.

The total number at nests, including twose either in the
process of being constructed or already occupied by a female,

' .33

was 74. In other words, there were 74 uairs o.

‘-

nesting birds.
It was impossible to set an accurate count of the number of

s it was a small col-

(I)

birds present in the nesting area unle
any in an Open area. nssuming a 50:50 sex ratio, the total
nesting population was 14;. The writer feels that this fig-
ure may be a little low {five or so), since there may have
been a few young females which were not nesting yet. ihe
population density was about 12.5 grackles per s uare mile,

or expressed in another way, it was approximately one grackle

Per 51.9 acres (possibly one uer 5- acres). The largest cul-

.L

cr
0.)
{l

onies consisted of l2 to 13 geirs, all of which were lace
within an area of about ane acre. In two cases sintle n srs
were found almost a quarter of a mile fram the rain colony.

In one place (Colony 6 of Fig. 10) a single air was located

over a quarter of a mile form the nearest colory.

A brief description of each nesting area will depict the
locations sought by grackles in this part of hickigan. The
nesting areas were numbered in the order of their discovery

(Fig. 10 and Table II).

 
 

 

 

.--, - - ‘ -\ ‘ --. . 1
['39 l. ". roux". T“: ' “V‘s": hf": .‘zu 363901 e ., 3 ll", . '-
‘I " I ' . q. ‘ I ‘ ‘ I I
tail (Liane: , ’«Jg n-' 'J' 0 ' J-.. w-V :4. . .._ . 1.: . I ' -. "~I‘J'

in that ar3a

Area a. Williams horn colony, lo c ed on the cam—
pus of hichigan State College, was cescr ribed earlier
(page ”5). Twelve nests were sitlated in Norway spruce
and Austrian pine. about half of them were su:per nded in
forks at about one meter from the ends of branche es, and
the other half were resting on branches.

area 5. Michigan avenue cilony was located on a
kuay separating the traffic of that stre et. oeven
ts are found in a spr: aiing nustrian pine at levels
ran ngin g fror 7 to la meters high (Plate 4, Fig. 5).

area 4. Bennett Farm colony was situated in a
windbreak of Norway sywric cs located near a farmhouse
(Fla te 4, Fig. B). These trees were about 40 years old
and were from l7 to 55 meters tall. Growth in the tops,
where all 15 nests were placed w s very dense. None of
the .rsts were below 15 meters above the ground.

Area 5. Forest Road colony with a total of eight
active nests was located in a small Spiraea'alba area
without Phalaris (Plate 5, Fig. A). A ninth nest was
found about one-fourth of a mile away in a small willow
swamp. “t the opiraea area the nest rushes were growing
in water from 80 to 50 centimeters deep. ' ’s lace was

 

divided by Forest Road into two parts. oeven nests were
located on the south side of the road where t.ere was
open water and where, also, the water ans deepest. A
single nest located at 5a, as previously mentionel, was
situated in the crotch of a black willow 60 centimeters

above shallow water (Plate 5, Fig. B).

area 6. This was a small willow swamp with button-
bush (tephalanthuq occidentalis) growing in water over

‘71..-“‘0- . .

one meter de Une pair of grackles was seen at this
Dl.ece on two different occasions Bec°“‘° of t.heir 8
tion“; sh“ ;;,l:vn;t act. .hlia‘ to ixre zrea, 'it ..,; .;:~
su ed th t €113“ ITFG nesting there.

area 7.- Collins Road colony was located in a willow
swamp where four nests were placed in the crotches of
black willow trees at a height of 65 centimeters above
the water level (Plate 6, Fig. a). The water depth was
30 to 40 centimeters. all of the nests were within
reach of an average-sized dog.

 

 

 

75

area 8. Gavanaugh Road colony with a total of 14
nests was located in a small willow swamp with a border
of sandbar willow (EQL2£.lQE§Z§QE) surrounding an open
water area in which was an island of black willow and
buttonbush. The water was over a meter deep except on
one side where it was 60 to 70 centimeters deep. One
nest was found in the sandbar willow thicket, susrended
among several upright branches of this shrub (Plate 6,
Fig. B). On the island 10 nests were situated in black
willow trees and two in buttonbush. Nest 8a (Fig. 10)
was located in a sandbar willow thicket about two tenths
of a mile from the rest of tris colony.

area 9. Two nests were found in a small, rather
open willow swamp. They were situated in crotches of
black willows l to 1.5 meters above the water. The lat—
ter was 30 to 50 centimeters deep.

area 10. The Music Building colony was located on
the campus in Norway spruce and Austrian pine. Six nests
were situated in a manner similar to those of the Williams
Dorm colony.

This survey of the nesting population of grackles in the
vicinity of fiast Lansing revealed several facts about their
rnunbers, distribution, and choice of nesting areas and sites.
There were ten colonies in all with an average of 7.4 pairs

in each; six were located in marshes and swamps with an av-

era ge of 3

Ho

x pairs per colony, and four in con'fnrcn: ro'

with an average of 9.5 pairs per colony. The nesting colonies
were in three general types of vegetation: (1) four colonies
were in coniferous trees (one in a windbreak near a farmstead

and three in the city); (2) two were in Spiraea alba marshes;

 

3nd (3) four were in willow swamps. On the average, the dis-

tame eilkftween a colony and the one nearest to it was 0.6 of
?¥“itl\e. the shortest distance was about 0.2 of a mile and the
9

5T37\~§ A“ about one mile. The height of the nests varied
er!

 

'76
rding to the kind of support. It averaged 10.5 meters
iniferous trees, 1.5 meters in black willows, 0.8 meters
110w shrubs, 0.65 meters in buttonbush and 0.55 meters
adowsweet bushes. from this variety of nesting areas
ites it becomes evident that the bronzed grackle is a
I adaptable nest builder and that, for the most pa rt,

:fers to nest in small groups.

iter ture. In general, the bronzed grackle builds its

n1.“— ._

 

rom about three to five weeks after the first migrants
the breeding grounds. In the southern states it prob-
uilds at about the same time as the purple grackle does,
is during the month of April in Alabama (Golsan and
914:22'7) and in late April to early May in Mississippi
rd, 1905:875-276). In the central and northern states
ilding begins at about the same time or a week later
it extends from mid-april to mid-Nay (Wilson, 1906z5;
, 1932:318-521; Trautman, 1940:590; Petersen and Young,
5) . In Ivlontana and in .xlberta, Canada, nest building
one month later, i.e., from mid-hay to mid-J une
1903:4123; Cameron, 1907:401).
S species is a highly adaptable nest builder, as was
from the survey of the East Lansing area. This trait
more evident in other parts of its breeding range.
Lfferent general types of habitat and as many dif-
rpes of nest situations were mentioned by 50 authors

iterature. These locations have been summarized in

 

77

a XKIII. The number of times that each type of habitat
1pgxxrt for the nests was mentioned by the authors gives
1eral.idea as to its frequency of use by U18 birds.
lflearly'all of the writers who mentioned the use of Cynif

a t hr «C ‘ I .l C‘
5'; - " ’\ ,\ , ‘ 'u-»‘.x, J. ‘\ \yasi J
‘ 5""! ;‘k'f_1'3.1 tlrldt 7')! _, -LL-L 1": - L- :._ T'i a .

than for nesting

s. In.connection with the use of hollows and cavities,
author pointed out the crudeness of the nest when it was
ed in old Woodpecker holes--they often used just a crude
.ng or none at all (Gibbs, 1905). apparently grackles will
: advantage of unused hollows or cavities in tree stubs
aher they are in an old orchard or in a flooded bottom-

1. The crevices in the sides of the osprey's nest are
etimes sought. Roberts (1958:439) related an observation
1. F. Kendall who saw several bronzed grackles nesting in
osprey's nest at a height of 18 meters (60 ft.). The use

several man-made structures has also been reported (Table

The bronzed grackle uses the material at hand for its
m and for that reason the composition varies from one type
habitat to another. This versatility is manifested in

avariety of materials used. heed stalk

(f1

, st‘cks, string,
>er,1ags, eelgrass, wood-shavings, corn husks. feathers,
?9flwir, and mud are some n {he materials found in nests

mice” in New England

".
O

apen, 1986:56—57) and in the Midwest

abrhflson, 1922:502). Compared with the nest of the Florida

78

grackles, there is very little difference in choice

nd the general structure of the nest (Bendire,

Egg-laying, Incubation, and Hatching

Lyigg. 0n the average, the first eggs were laid

'ter the lining of the nest was completed. lhe

are one and four days. Eggs were deposited in the
.ng hours from 6:00 to 8:00. The single exception

; 16, where the first egg was still warm at 7:50 P.M.
) warm eggs the second day at 10:00 “.m. hither
a‘was an erratic layer or she began incubating with
:gg. All females deposited one egg per day on con-
ays, except the female of Nest 8, which apparently

3y between the second and last egg.. The petal hu'«
a laid was 4.5 per nest and ranged from three to six.
of egg-laying at Trowbridge harsh was from April

7 in 1951 and from april 25 to way 7 in 1952.

55. The background color of the eggs was of two
.) a dark shade of a tarnished or rusty color, (2)
ads of either an aqua or a pale blue color. Each
only one of these two background colors. Gentry
described the eggs of the purple grackle, "gals-
Hfiflé (Bartram) Licht," as follows:

Jund (color) is also subject to changes, specimens
seen with a deep rusty-brown color, and others with

 

 

“r

 

79
one of light greenish-white. It is a rare occurrence to
meet with the two forms in the same nest-full, the latter
being the predominant hue. figgs with the brown background
have in addition to the black and dark-brown streaks and
dashes which cover the other type, chiefly about the
larger extremity, a number of confluent, cloudy blotches
of deeper shades of the same color. These markings are
singularly grotesque in their pattern, and often bear
strong resemblances to letters, figures and other charac-
ters.

eed (1904:245) said of the nesting habits and eggs of the
area subSpecies of quiscula: ". . . The nesting habits and
ggs of the subspecies of dais Grackle [the purple grackle]

3 not differ in any particular." This is supported by the
act that the color characteristics of die eggs of the bronzed
rackles at Trowbridge harsh agree with Gentry's description

f the purple grackle eggs.

The length and width of 20 eggs from five sets at
rowbridge Marsh were measured. These measurements, compared
ith average figures reported by Uapen (1886:56), who measured
pecimens in New England, and Reed (19042245), who gave the

verage size of the eggs of purple grackles (the locality

as not given) are as follows:

average Length average Width
hillimeters Inches hillimeters Inches
Trowbridge Marsh 28.85 1.12 21.95 0.83
Capen 51.75 1.25 22.86 0.90
Reed 27.94 1.10 20.32 0.80

is length of eggs at Trowbridge Marsh varied from 27 milli-
3ters (1.06 in.) to 30 millimeters (1.18 in.), and the width,

30m 20 millimeters (0.79 in.) to 22 millimeters (0.87 in.).

 

 

80
Incubation. The female does all of the incubating,
nich she commences in the late afternoon or early evening
rior to the laying of the last egg. This differs from the
)at-tailed grackle, which begins incubation at the laying
F the seecnd egg (hellhenny, 1937:2823. bnly a few instances
are found where incubation had been started before 5:00 P.h.
net of the eggs were still cold at that time. However, in-
ubation certainly begins at least 12 hours before the last
gg is deposited, since hatching of a set requires two days.
The female soon establishes a routine way of entering
nd leaving the nest. She usually alights on a lush top 10-
ated 15 to 20 feet away, and, after a brief hesitation,
escends out of View and hops from branch to branch along an
rregular course to the nest. She nearly always enters the
est from one direction and leaves it in another. Usually
he approaches silently, but sometimes makes a low "check"
r "churr" just as she enters the nest. Very often she makes
imilar sounds when departing.
0n the nest the female is alert and uneasy much 3f the
ime. Uneasiness seems to be more pronounced on windy da's.
Probably the movements of the blind were responsible for
ome of this action.) The female exercises in three ways:
1) by shuffling her feet as though turning the eggs, (2)
y backing up on the edge of the nest in order to reach be-
ow her breast with her bill to turn the eggs or to clean the

est, (5) by turning from one position to another. These

 

81

do not occur at regular intervals; sometimes the

~etween them is only a minute, at other times it

minutes, but generally it is about 10 minutes.

L a shuffling movement precedes the departure from
‘rurning in the nest gives the bird a chance to

1 little, which probably relieves fatigue. bome

early always turn in the same direction, while others

Ln either direction.

male spends about a fourth to nearly half of his
perch 20 to 40 feet from the nest. The female may
the nest while he is present, but she usually is.

3 attentive from about 8:30 “.m. until noon and again
to 7:00 P.M. as compared with the earlier and later

;he day. uuring an observation period of one and a

3 on the morning of the sixth day of incubation, the

3st 6 was present 41 per cent of the time. On the

iay, during a five-hour morning observation period,

esent only 17.6 per cent of the time. On the tenth

3 an afternoon watch of six hours this same male was

2W4 per cent of the time, 10 per cent of which was

a female's absence. While he is on the perch, he

eries of three to five calls to the female. nfter

al of quiet for two minutes or more he repeats his
vmich the female may answer with one call from the

3 main function appears to be guarding, because, when

as alight on the same perch in his presence, they

rt.

 

 

 

82

.g the morning hours the male visited the nest on
;e of once every two hours; in the afternoon his
“e less frequent. as early as the sixth day of in-
Le was observed feeding the female while she was on

When the male came close a) the nest, the female
agged with fluttering wings like a young bird. Once,
alfth day of incubation (very close to hatching
a female uttered a warning "churr" as the male came
;he nest.
1g incubation the reaction of female grackles to in-
aried from one individual to another, but, generally,
1em flushed when the inVestigator was about 15 to 20
. (The closest was four feet.) after the female
ed, she usually flew to a perch and objected by
‘ or "chucking." 1f the male was present, he joined
jection and perhaps added a few "churrs." Occasion-
nale would fly over the intruder and object more
y.
length of periods of attentiveness during incubation
new1at according to the time of day and to indivifl-
rences. The females of Nests 6 and 17 were observed
ular (Fig. 11 and Table X). The female of Nest 6
about 16 minutes per period on the nest both in the
ad afternoon, and remained on the nest a little long-
beginning and end of each day, when the temperatures

ow as 12° t. The inattentive period ranged from 10

 

83

Female 6
Tenth day of incubation
Ray 14, 1951

 

L l l L

 

:0 4:00 5:00 6:00 7:00 8:00
2st: 169 min. Time off nest: 191 min. P.k.
Female 6

Eleventh day of incubation
hay 15, 1951

--------I
5— 6:00 7:00 8:00 9:00 10‘00
est: 160 min. Time off nest: 155 min. h.h.

Female 17
Seventh day of incubation
May 9, 1952

‘j

 

 

 

7:00 8:00 9:00 10:00 *11:00 12100
ast: 249 min. Time off nest: 111 min. n.N.
Female 17

Tenth day of incubation
(may 1}. , 195;:

 

 

‘ IIIIIII I III . I!
5:00 6:00 7:00 8:00
Time on nest: 96 min. iukg

Tine eff nest: 210 min.

g. 11. h record of attentive and inattentive periods
males incubating. Shaded portions of the bars rep-
off truaziezt.

 

 

 

84
utes. The female of Nest 17 remained on the rest
longer intervals, averaging between 45 and 50 minutes.
rature was between 3°and 10°C. when this female was

Other factors, which will he discussed later, may

ed her to remain on the nest for periods longer than

ccurate check on the length of the incubation period

:1

ts at Trowbridge harsh showed an verage of 12.7

days for two nests and 13 days for eight others.

1 of the incubation period was computed from the

the last 888 to the hatching of the last young.
actions of 33 nests with eggs were made nearly every
awbridge harsh, Forest Road, and Collins Road 0010-
Efilt tfi‘ LEExn? ti? he:fi,e xrnne denierten‘, a Irinth 1..d i_ts
an, and the female of a tenth nest was killed. Nests
involved 23 per cent of all the eggs laid in these
while the other two nests involved only three per
lumber of factors-—some known, some unknown—~caused

. Known factors included weather and interferences
restigator. Other possible causes included the in-
;siological make-up of the bird and also some complex

_ationships that were not observed. an account of

sts, which were either deserted or destroyed, fol-

>ut one of the eight females which deserted were

to about the same amount of interference by daily

85
18 of their nests. The female of Nest 17 had an
int of disturbance because a blind near her was
>wn by cattle and set up again several times.
Dbjection of incubating females to the intrusion
lestigator was not as vigorous as it was later when
e in the nest. There was no correlation between the
objecting by the females and their tendency to de-
serference was, no doubt, a contributing factor to
iragement of some that lacked zeal for incubating.
vorable weather, that is, a period of two or three

preceded the desertion of five nests

.L

31d, wet weather
idge Marsh in 1951 (Nests l, 5, 7, 9, and 15), two

is same marsh in 1952 (Nests l6 and 17), and one at
ad in 1952 (Nest 8). Figs. 12 and 13 give a graphic
f the correlation between desertion and weather.

re was practically no cover above these nests, the
ere greatly exposed. The urge to incubate under pro-
verse weather conditions probably waned in all

and those already lacking in zeal in this respect
lost interest completely. Desertion in all cases
after at least five days of incubation. None of them
.dh.in the same nestingz-rea.

female of Nest 17 had other disturbing factors in

to weather. Interference by placing a blind near the
already been pointed out. There was also a third

ich is not clearly understood. On the morning of

86

45:5 .237 as l 3 5 7 91115151719
I TIITTI

 

 

 

 

 

 

 

 

 

 

00 I I r I l T ‘90
85 +85
80- -BO -l.O
'75 -75 - .9
'70 «'70 - .8
r. 65— '65 "" .7
{‘4 L
‘3 so § -60 - .6
s \ "1
@55— g -55 - .5
Q) T
"U
"—1 l
"’ Q) 45 ' -45 " .3
:4 V \ ,/ l
2- i340 \ '/ ' -4o - .2
a Y \ '5 .'
l
,1- <9 :55 ‘\ , . J35 - .1
if: L \ A i g ' ‘u
.0- £3 :30 .‘—.3R—E§'Ey--' 1 s ’“r-J Lr— -1 1\"‘1 -30 .- .0
'7 9

'1
252729 15 5

Fig. la. The correlation of rest desertion with tem-
:reture and precipitation at Trowbridge harsh colony, 1951.
ach bar one unit high represents one nest with eggs.. (Data
ron Station Meteorological summary for Lansmg, 1..ichig:_zn,
.S.Department of Commerce, Weather j-Tureau.)
the day when this female deserted, it was noticed that the male
was not around as much as he had been on other mornings. when
he arrived, he was accompanied by another female. both females
responded to his call as he approached the nest, so he was as-
sumed to be the mate of the female of Nest 17. The writer
strongly suspects that the second female may have been the one
of Nest 16, which deserted three days previously. This problem

of sharing her mate may have been a factor contributing to her

desertion.

 

 

8'?

25237 2.9135791113151719
T I I I I [-90

go‘fi I I I I I T
85 ~85

 

 

 

 

 

 

 

 

Fig. 13. The correlation of nest desertion with tem-
reture and precipitation at Trowbridge harsh and Forest
ad colonies, 1952. Each bar one unit high represents one
:st with eggs. (Data from o‘tation meteorological Summary
3r Lansing, IMichigan, U.S.Depa rtment of Commerce, weather
creeu.)

The eggs of Nest 2: were broken. It is not known whether
they were broken by her, by some other grackle, or, perhaps,
by some other animal. her rest was more exposed than any of
the others at Trowbridge harsh, since it had been placed on

a Spiraea bush which had been pressed over on its s51? ‘. The

stem

(0

of this hush formed a ran; leading from he cater to the
nest, so that entry by a water bird, such as a coot or rail,

would have been easy. Another possibility is a crow, since

 

88
some were seen at times over the marsh, and were always
chased by the grackles.

The female of Nest 30 was caught in a trap and killed
by dogs before the trap was inspected.

at least six of the eight desertions, therefore, cor-
relate with prolonged cold, wet weather, which is understood
to be the primary external factor causing desertion. The
lack of or loss of a mate in addition to adverse weather may
have been the cause of two other desertions.

None of the nests examined in this study contained a
cowbird's egg, although one red-Wing's nest at Trowbridge
Marsh contained one. Friedmann (1929:215-216; 1931:61) re-
ported several cases where bronzed grackles' nests have been

parasitized by the cowbird.

Hatching. Hatching appeared to occur at any time of the
day. One young was observed in the process of hatching at
10:27 nth. Several hours later, at 5:05 P.L., a second young.
with the capital down still wet, was present in the same nest.
Another young with wet down was observed at Collins Road

colony at 5:15 1.h.
Growth and Development of Young

The growth of young grackles was checked by weighing,
and by measuring the length of the bill, wing, and tarsus

nearly every day at three nesting areas. The ideal way of

 

89
making this kind of a study would be to obtain such data at
the execs time of hatching, again at frequent intervals dur-
ing the first two days, and then daily measurements until the
young are ready to leave the nest. AS the investigator was
not able to do this, it was hoped that by having a fairly
large sampling from three nesting areas, a reasonably accurate
picture of the growth of young grachlos in this region might
be obtained.

Weighing and measuring KLS done in the late afternoon in
nearly every case. During tlis study 410 weig.ings and sets
of measurements were made on 77 different nestlings. The day
of hatching if as nestlings was definitely Known; it could be
estimated for the remaining 48. The data on the 29 young
were used to compute the amount and rate of growth.

Since measurements were not made at the exact time of
hatching, seven young, viichxwere known to be less than eight
hours old, were used to represent the at—hatching age. it
was believed that none of these lad been fed, beCause m;ey
were all about the same weight (five and six grams). all of
the young in the day-of—hatching class (zero day) were hatched
Within a b4-hour period. Some were newly hatched, others had
been fed several times; therefore, the weights and measure-

ments varied considerably (Fig. 14, page 101).

£_ hatching. Weight 5.5 grams, bill 6.4 mm., wing 9.0 mm.,

tarsus 5.5 mm. (average of seven young less than eight hours
old).

 

 

90

The skin of a nevly-hatched chick is bright yellowish-
orange color on the ventral side, which shades into a darker
blue-black on the dorsal surface, especially on the tor of
the head and in the gelvic regior. The margins of the till
are yellow; the lininq of tie mouth is triaht reddish-orange.

The newly—hatched chick is nearly naked except for down
.which is 10 to it sillineters lJn: :ro rovers the Cfifitfll,
spinal (except for the cervical region), humeral, and femoral
tracts. The ventral traxt is naked. on the alar trac a few
long tufts of down (14 to 15 mm.) are lccct d along the line
where the first greater COVwItE of the secondaries mill ap-
pear later. at this age n‘ne of the future juvenal feathers
are evident even as darkened areas under the skin.

The eyes are comgletely closed. the eye slit is 2.5
millimeters long.

A newly-hatched click. just out of the shell, utters a
faint "peer", raises its head feebly ard opens its mouth in
response to almost any sound or vitratien near tle nest.

This is also true of the older ores in the day-of-hatching

Day f hatching. weight 6.5 grams, hill 6.2 mm., wing

9.6 mm., tar us 6.2 mm. (Average of 29 young hatched within

(0

a 24-hour period.)
The larger members of this age class, which were assumed

to be older, ap eared to be a little stronger. in the hand

 

 

 

91
they were very limb and made clutchinr rovements with their
toes. The skin color, down, an: reactions were the same as

that of the previous age group.

gag gay. weight 9.9 grams (7 to 18), bill 6.8 mm., wing
11.3 mm., tarsus 7.5 mm. (average of 30)

The down persists in the places described previously
(Plate 7, Fig. 4). The orly indication of juvenal feathers
is the apnearance of a cark hervy line under the skin of the
wings where the future primaries and secondaries are develop-
ing.

The eyes are still completely closed, the eye slits are
a.5 millimeters long. The voice and reactions are the same

but stronger.

Two days. Height 14.0 gr ms (8 to 19), bill 7.6 mm.,
wing 15.7 mm., tarsus 9.6 mm. (average of a8)

This vide variatisn in weiglt can be accounted for ly
the fact that in ‘csts where there zere five or more young,
not infrecuontly the youngest L88 so orcvdec and covered 1;
the older nestlings that it did not receive as much food,
and, after two to five days of virtual starvation, died.

Dark points and dots under the skin mark the location of

‘

O
Y‘

rln feathers found on the spinal (from the lower cervice re—
gion to the tail), humeral, femoral, ventral, and alar tracts.
There is no indication of them an the cagital tract or or the

urper cervical region of the sginal tract. host of the prim-

 

 

 

0

.~,
1:,

0

ary pin feathers hroject thrcurh the skin about one milli-
meter. only the first txo or three }in feathers of the sec—
ondaries have pushed out of the skin. Ihe rehaihder are
merely pinples of flesh. The yin feathers of the alula keep
pace with those of the grimaries.

The voice is a faint "peer.” The eyes are still closed
but the slits have increased to three millimete s. The young
responds to sounds and vibrations among the bushes, as before,
by holding its head up with neck stretched and south open.

It makes clutching movements with the fe?t but does not hold

on to anything.

Three days. height 19.6 grams (10 to :9), hill 8.8 mm.,
wing 17.4 mm., tarsus 12.5 mm. {Averade of 51)

Pin feathers appear as rows of dots through the skin on
the spinal (intersCagular region to tail), humeral, femoral,
crural, and ventral trac.s. There are none on the capital

tract. A row of dots under the skin on the oaudal

('1’

ract rt'rhs
the loeation of the upbcr tail ccverts. Un the slar tract
the longest primary and secondary Lin feathers protrud about
two millimeters.

The eyes may be seen through a slit which is 3.25 mil-
limeters in length. ln res;onse to the sound of the writer's

aPproach the young pop u; their vibrating heads and "peer"

with cpen mouths.

 

 

 

r- l -|

Jour days. beirhf ”7.5 3: as lit to 58), bill 30.0 rs
wing 25.0 mm., tarsus 15.0 mm. (average of 15)

The skin is looser and much darker than that of the nav-
1y hatched chick. Unly the anteria of the sides and chin have
the bright color »f the younger chick. llumage develoiment
has advanced (Plate 7, his. B). as yin feathers grow out in
areas of hotel down, tufts of the dovn are carried out on the
ends of them. All trsc s hut the c git l have tiny ,ia feath-
ers. on the spinal tract yin feathers are largest in the
interscapular region. heather development is most advanced
on the alar tract. The primary pin feathersejre out from
5.5 to 6.0 millimeters; those of primaries Lumber 1, e, and 5
are the longest. The greater covert pin feathers are out 1.5
to 5.0 millimeters and the lesser coverts appear under the
skin.'

The eyes are open a little and can be seen through a
slit 5.5 millimeters long. The voice is a lcud, coarse ”peel”

l
L, A...

that is used for begging for food. ror the first time the
young clutches the nest lining when it is lifted out of the

nest.

Five days. weight 54.5 grams (22 to 44), bill 10.7 mm.,
ving 39.4 mm., tarsus 18.5 mm. (averaee of al)

The capital tract becomes darker as pin feathers develop
under the skin. The first pin feathers appear on the cauital

tract in the occipital region as a few pimple-like projections.

 

: .
v ‘ a '
, . 7: M r ,\..
I l I . Avr‘ /.. y n
a . Vu‘. ‘
l. . v 1 a . 1 .v, w
. .r. M n. ) . .
JR 1 . . .
. ._ . I.» p ,.

 

94

alona the spinal tr ct thk .in Ucathers are now one Filli-

4L

meter in length in the interscaiular region. hlsemhcre along
this tract they are shout 0.5 millimeters. iir feather
develoyment has advanced in the some pro,ortion along the

humeral, femoral, ozgfuL, v htrul, and caudal tracts. The

under tail covert gin feathers have not yet a;

C1:
0
:1
k.’
C)
:5
“1

years. _.
the 3 ar tract the yrimory quills have pushed out noticechlv.
The first prim r? is elout 11 millimeters and the ninth is

about 7 ”111‘"“ er:. The second rie and fronter coverts

(0

have advanced prcoorticnetely. a few lesser coverts no“ gro—
ject about one millimeter heyond the skin.

The eye arena 2 little wider hut th

(D
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. ”'3
CK?
L—Jo
y—Jo
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slit about 5.75 millimeter long; The vcijg i C loud and

(I)

(I)

excited ”peepinr”, audible at a distance of 10 to 15 mete s.

(')

They still react to sounds and vihrations shoot the HsLt a
hefo e. when one is held in the herd, it clutches and hangs

on to a fingger.

six da's. Height 42.8 grams (L7 to 57), b

F. J .
H
H
p...)
H
0
{.71
L3
is
I

wing 56.0 mm., tarsus h0.6 mm. (Average of 18}

There is a general increase in the length of he Llh

, '~ ,. . ~. . r- 1 .. .~.4- . p .. -. - ' -.+ 0 "a
featieit “LKLH all U1 the tracts. u 1-“ nth orcgect .r'm the
o o q ‘ t ‘p ‘ o 1 rr" 7. -‘ o D . -
OkClpltJ- ~ or the no ital .raxc. in: ”.ilcl -in leath-
.5 L
r , o a. J— ' L - - .. ‘ - fl ‘ , n _, -
are L. one resur_ze~ naJc Cilbur'n v» ~JV3 tu359 ‘1 tne ’31“

r-J

tral tal coverts. The lrima1 y cuills are

' 1. ,fl .n. i ;' -.\.- -,.- p
limeters long. N he cf the re ther ell: have Ioken Lrom the

g .

sheaths yet.

 

 

 

"‘5

-.1 . -+- .r. -. M ‘ . vv/\: :- ' . . r . \ ‘ - 'r
niiltneters in length. Lhe vcice end generul reaction; d1:

- ,.O , p.‘ ",.. l“.
,hcse Us the iive-uuguold epic.

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Seven tgys. Heinht 52.8 rrcne ($7 to 55), till 14.5 um..

 

wing 46.1 mm., tarsus 44.5 mm. (Average of 15)
at this age, feathers ere just hegiiuin: to brec< out
of the ends of the quills slang many of tie tracts (flete c,

Fig. A). Natal down is still ire;ent in all of the orixinel

L‘s

m
C)

oleces, but is now an the tips f quill r adhering to feath-
er tits. It is most noticeable on the eepitel tract where

the pin feathers are merely em:

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A -. . O ' '1 - n \ r 'v. "\ \- ‘- -~~ . " r . ‘ . \ 1" '. r ‘\
skin. tin feather” aie from four to :l. MllllmECBl: lJ lengt-

trices .uxainminlv one vfljfitheter in 1.3.3th. The ‘ru; feath-
ers, .1 ien ere tee uo—‘t cGVgr. :ec, E1 n =3 tne feat»: In: DIC‘ECiJS
out of the brimcry sheuths a: long es 1.5 rillimetcre. The
rete of growth of the first tfree QrTrcry guillr tc- “-eH

faster than those tenurd the ninth. ”he arineriee are 15 to

“'c‘.- ‘ .
a3 airtimetere long.
I. 'I -. .x . IN .' 1 V \.-‘l I' Q 'r‘ ‘ I. 5' :‘
lhe eyes are heuriy tide ogpn, enu -o: the nlfzt t-ne

'ru . .~ . .t..‘ 90,, " - .- '. . -. A—r “--
J‘lv yOMIlE, :nOV. ;,.L-‘_AJ.:,' Oi. .LBJF. 1110:] 771.13] Crlflg—ZL‘) QOdflbUTrll‘}

and then suddenly begin begging vith up—str‘triefi, vibratinc

fi“ .x‘ .~ ‘1'“ - . ‘ ~ ‘.1 o a. '1 r. , 3".
luccxe, (is frir.ui:is OVbIKlnnj by l nuger. CMiey elsC)-xrtnbe

s a tuxirse 14y fin"

F).

.L‘ o . _ . -
uuen the {create act excited. 1L: VQlUu

"peep."

 

 

_Lj..i__y_1.t -._;.-_;;._. :31" (3:: t- m). .17“. i.“
\nin 1 51.53 rad , t . as .ef.i 1LT. { a: 1-:v, oi' i?)

:1"; tlu‘if '1- :; JL": 51‘ =_ ..1"" :05 ‘LM 3.1‘} ‘.’_~ iw T I“

u s. - J

UTCC tnh.. “the -n;4fl; ”e fi.J’ tiff Lfl”):wuf " ;m ?L ;h:e
uh e71. Q? ‘3. tretflm;. if“; Cegitifl. tr t-.iUJL .L. Liri'?3
Trt~u rle fix: thj‘“” [tiliigtef.3r' Fusn;;..itii the ?.e*”‘ r L.if
jecting mcu”~ 3.5 o” e “L‘li;eter. Th: “iille ” the :
ur‘ees ere sit t. :1aven "illirn4n3rs (it? l~xflflner ti;s c
:111'meter. Ch tt tier treei, grin ;; F=nter 1 i; ‘;
n_ill'uneth3rs i.etg ernl t1 e faiet.1er Lhr01zy3ts ‘f‘ccu ti - .;;i3
t'-'U ‘17 fClzl Jig-111;: t'i‘l‘ko

The eyes ere ”cw l'fistg n; (wju slit, 3.5 gh.;. Th
govrg cringe at first, hut utter a trier gtri.7 .? ufije
.A.ey ”iii..;tick their-Evanis u: LIViiJQg. Ihe vols“: is e
ing from the coarse ”Leer” to e scr¢eehy "peep”, WLiCh
used for beggirg ? r feefi. Young at fl is age are deiir
r,“ -‘— 2 +4 .— ‘ I" . ...‘, ... n- .3
hole active in the best. PheJ C.q=i ere.rd -z.m .n~ si
‘iie ..3:3t ta) t} e .it1.:r ;.n i o 33a.?iCJle1-L}' f1“. t.-cnir . 1-2i5
raise their bedi;s up to defeCnte.

flipe Gaye. Height 58.8 grams (45 tc 74), till 1;.

3

CI'
(3

f

still

The down

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are out CW

does not have

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on the

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ence of using camgletely f

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ath-

 

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erefl out. The lrimsrie-s are ohrut 7” 'illireters .ith tie
feathers tro]ec tin: 5 to 1C r‘illirneter. Jrom .he sheetht.
Thfi>39in f (ire of ti reetriyvy‘,.re eigfifii::illiriitcrs erfl
the feather tifs ere out 1% rillimetgt. ns t.e elietle JLPK
bits of them flout off so thet seeles soifimulote in the east
‘The 'okn etill TGPE‘PJ ,3 e “TQEC hiro's 1P.I(ULUZ hy
shooti n3 their oten mouths utuurd .nd vi‘retLrj t‘eir stif-
fened necks vigorously. One tee blur“ to gi"e the ”location"
cell flute a few times at this ese. This 1s a single, double,
or triple nnte, vhich sounds much lik~ tue »<ult’s "ehec <,'
but has the quality of a "chirp." Hhen an ?l“z“ “git r if .

nest uttzrs this note, the younger ores immediately leapond
to it us de‘cribed ter th nine-dey-old young.

Ten_dazs. Weight 67.8 grams (51 to 75), bill 14.7 mr.,
hing 65.9 mm., tarsus t9.e m2. leverov= 0. nine young)

Tufts of down are still prm niinent on the e gitol tract.
The primaries e e from 40 to 45 millim ere long end the
feathers urogect 13 to go millimeters heyerd the eno of the
sheaths. Th breast enu nic: are fairly tell covered .ith
gray-brown fee thers. The reetrices are atout 10 millimeters
long with the feather tits pr be ting thr to five milli—
meters.

The "location” note is used for begging for food most

of th

the note becomes

Q

L}

e time. When the nestling i actually reoe iving

a buzzy, begging sound.

food,

donetimes the

 

CL‘

young stand up while begqing, instead of stretch-n3 their

.180}:

m

1 a v u; , n \V' 4 - .- p.
up‘fifd I": , ho lvd‘] ‘JF, (K): t (.2 1 th 63 t *IT.'3 tr- *3 ‘-
the manner 9r3Viously deseritev. vhen tne youns ore ver”

‘~£:)

active, they move about much in the ”est aid on the rim of

cf

One may stand up straight and stretch its wings outmurf or
downward to aid in raintnining its bwlunoe (Piste 9

The young are arle to perch on one's fin"er or nt-nu r their

(0
Ho

ter 2n the rim of the nest and flutter their tings. at

H-

t m

(D
m

I)

when they are lees active, they merelv stretch a ting
or green the feathers of their tins: hreusts or
When at rest, they are very often so situated hat ell ore
facinq the side of the vest r"rem which the
(Plate 9, Fig. B). On hot days they move epurt, some on the

rim and some in the cup of U

k.)

nest. They rent like on adult

bird to reduce the body ten‘

1.
A

... r ’ ‘ ' ,x . \ . ‘ ax ‘
quturj. .hen an litrlddr u-»

A:

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1

proaohos the nest, the young cringe ruffle their in“

’ .IJ

( 1'
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and "churr" like on adult.

Aleven days. height 73.5 grams (65 to “4}
mm., wing 70.3 mm., tarsus 49.7 mm. (Avera,e of four)
The feathers have rushed out of their sheet.s so that
the young now look like birds (Plate 8, bi"° B and G).
The primaries are only a little longer, 45 to 4‘ rillimeters
and the feathers ere out of their sheaths e little further,

15 to 25 millimeters. The reotrices ere 15 to so mil meters

r. J
FJ.

and the feathers are out 5 to 10 millimeters.

 

9 o
The activities of the young, which include Lcrchns on

the rinx n“ Hie nest, stendinr Iv.'fib1tterinn tre \jif; .u‘

stretching them, preenins, and actively roving about in the

nests, are e‘out the cane as those of the lO-day-old nestling
except that there is car; of it. when wne spproact:s the

nest, the young cringe end ru- is their festters. 1f an? is

lifted from the nest, it why utter a loud "churr" of obiection

C)
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H
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and then jumo out. several attempts were made to 112
back into the nest after they had jumced, but they toul“
remain. Uccasionelly one would jump and fall into the water.
It would swim to a branch of a bush for safety. One was so
exhausted from trying to swim to safety that it vouli have

drowned had it not been rescued.
’

Twelve davs. Weight 79.0 grams (74 to 3;), bill 16.0
mm., wing 75.0 mm., tarsus 51.0 mm. (Average of two)

The young are congletely covered by feathers except for
the area around the eyes. Tufts of down on the ends of the
capital feathers and a few of the feathers of the funeral and
alsr tracts is characteristic. at this st fie of develcinent
the juvcnal plumage is ;::xx€t brawniSh-qray color on the under
parts and a dark gray to a black on the upp3r parts. The tsil
is short, v rying from 15 to 30 millimeters in length with
feathers urajecting from 10 to L0 millimeters out of their

A

hany young leave the nest at this age.

 

 

 

 

lOO

Nest leaving. Normally young grackles le.ve the nest

 

when they are la to 14 days old, but if disturbed they may
flush at ll days.

Nest a5 with four young was closely observed for several
days prior to nest leaving. uaring the last three days the
parents teceme more sensitive and excitalle than they had
been Lreviausly. One of the young, which was a day older
than the other three, flushed from the nest on key Bl when
it was 11 days old. The other three merely cringed and
"churred." The next day at 10:55 A.h. the female coaxed the
other three young from the nest in the following manner.
After feeding the young, the female moved atout among the

bushes near the nest uttering a soft "chuck." The young

{3‘
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responded with the ”location" note and scrah
other in an attempt to go toward her. unilfl she gcnfinued

o . , o . . . .
flr‘ . . - t ‘v , n 3 F, 1 ‘ L‘. \V. \I v I" ' \ f’ -' va.‘ “ ~ ~ 9’ I. 1‘ .-~' _v ‘ -. q ' - ,-.
k‘JUk-n’:\’ ULLL. OJ. - -- _, J M L-,' Li‘ 4U r- \J-L lt‘? vl'lL.' \ ~ ~— 11: ‘lf.: t:\

\~\ 14 \'\ y- ., x\ 4|- 3. 7' ~ 4- T n g; :1 n ”‘2, 1’"; ' I‘ I ‘ "‘- - ‘
to u 1).]. 1”qu “Qt L w .‘u ' "it- b. 4n _. 1”» . “\-- rlv 1 L x:[ ... 1A3 ' FF:
p, P ‘, .4. ‘2 .- ‘. - ‘ .-‘ , .- p . _ fl ' . '

_ .1“; ,_. f: . Y, r . - r V‘ .. 3 i . . ,. , ,. -. o 1 ~. - v
Vut O L 1; LA. \-' I". J K- L‘ *1 ~J‘ J 1-/"‘ I. -A .. L-- .4. iii! _. \.— .L V\A. .-$.. 1 ._1 ~__r: A : ~ 5AA ‘IL , 1’ I... V .-

1ng the ”location” “rte in 1hytir.

Growth. Young bronzed gr chles grow raiidly during 1a
days of nestling left. lhis is reflected in the ragid in-
crease in both weight and‘xing length (Fig. 14). A newly
hatched chick, for example, will gain 15 times its *eight by

the tine it is ready to leave the nest; its wing will lengthen

nearly as much. Change in the length of the tarsus and bill

 

 

 

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weight
o-o°°"°" bill length

65b - - -- - wing " -55
'-—"-" tarsus "

. 60-- -60
w
3 55" -55
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E 50- —50
-H
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E
2:40” —40
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£5” -25

 

 

 

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$4

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C4 ’ ./ ........o...o.oo 00.

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.- CLI l J l J l l l 1 l l I L10
0 l L 15 4 5 £5 7 a $2 10 11 12

Fig. 14. Daily LWOUHt of growth of nestling bronzed
grackles. (Trowbridge he sh, 1951; Collins Road nd Forest
Road, 1955.}

is not as pronounced, the former increasing six times and the
latter about three times during the period.

The rate of growth (in weight) is not constant but shows

a definite retardation between the seventh and tenth da's.

 

 

102
‘Phis ii: 818 the period when the bird is feathering out.
although changes in analxmgth of the wing<h31tm;show the
overall rate of feather production, it does, nevertheless,

give sauna indication of it, since increase in the length of
the gumhmaries was included in the measurements of the wing.
It vxtll be noticed that the rate of increase in the length of
the wiregwas greater than that of weight between the ninth
and tenth days. This indicates that the rate of growth is
retarded at a time when feather production is high.

How do fledglinrs lb days old compare with adults in
weight and in length of the wing, bill, and tarsus? The
writer collected 15 grackles (4 adult and ll juvenal) of both
sexes during the month of august in 1951 (the melting season).
The juvenal birds were so near the size of the adults that
they are all classed as "adults.” Following is a comparison

of the average weights and measu

*3

ements of fledglings and

"adult" grackles:

' - '1‘ ‘- : '9 IP‘ '2 1 -1 ‘ ' ‘
..eigna ting :,-ll larsis
" \ r r v'fi ' - q 7" . . «I I A I
Fledglings 9.9 g. .a.o Km. i6.c mm. al.o mm.

(xv. of 2:)
"ndults" 114.0 g. 153.0 mm. a7.6 mm. a9.0 ma.

(iLVo Of 1.5)

From this comparison it can be seen that the tarsus
fully developed by the time the young are ready to leave the
nest. among the "adult" birds collected, which included
eight males and seven females, the tarsus of the males aver-

aged a little larger (49.5 mm.) than did those of the females

 

105

CD
cf
if
('1:
E
f
U)
‘3'
(a
53
(L
:3
C+
(I)
C

1
Cr
M
q

(58.0 mm.\. Sine two fledglihfs

were large, they -roLetly were wales. Aside free the tarsus,
the other eeasurements and the weight show that the fledgling

is about half grown.
Nesting Success and Mortality Factors

The rate of reproduction was lower and mortality was

higher anong grackles nesting in marshes and a Shemg at ast

t1

Lansing than among those at hadison, Wisconsin, where Peter-
sen and Young (1950:471) examined two areas ov;r a three-yea
period. Table XII shows a comfarison of nesting success be-
tween these two localities. The lower rate of reproduction
at East Lansing is reflected in three ways:

(1) by a lower ter cent of successful nests, i.e., nests
that fledged a} least one young (35 per cent comlsrcd to 55
per cent at hadisen);

(a) by a low r per cent of eggs that hatched (63 com—

CD

pared to 75 per cent);

(3) by a lower number of fledglings surviving per active

nest, i.e., nests xith ,t l~ast L;e :gg. (1.1 cow; red to ..p
per nest at hadison). Table XIII shows the nesting success

of the f0“r colonies ob

U)

erved at east LahSing.

n4"

st

(b

There vere several factors which were the cause n

failures at east Lansing (Table XIV), viz., weather, treda-

tion,infertility, broken eggs, desertion of young, young

dying in the nest, and bonded young removed by the parent bird.

 

104
Des ertion of LB per cent of the eggs laid mas attrib~te
to beci‘weatlun?,e;s was («lirted (Nit prurriously (gnzg e 81).
Two of the nestirC localities, viz., Trowbridge harsh and

Forest Hood, where de ertion was high, vere unyrotec ted from
wind and grecipitation. hes ertion due to bad weather did not
occur at the Uollins fioad colony where the nests were she -
tered.

Predation of two types destroyed 56 per cent of the 145
eggs laid (all i.ere nestlings). Twenty (er cent 0. t“ese
were taken by unknown predators and six per cent were removed
by the investigator for stomach anal lysis One of the {red—
etors at Trowbridge harsh was believed to be a Cooyer's hawk—-
it was observed flying low over the marsh several times dur-
ing the two years of study. On one occasion when the rest-
lings uere betxeen five and eight d;ys old a Uoorer's hawk
swooped down near the site Of a grackle's nest, but failed
to take one. Kingtirds and crackles ctased it cu of the
area. On another occasion, when the young of Rest :1 were 9
to 10 days old, all of the young disappeared at one time.

The female of that nest had had some of her tail feathers re-

moved. This may have b~en the re ult of another attack by

the hawk. (Under sicfi l.rar circumstances the female of n38t 45

was seen to cover be er young when a dooter's hawk gassed over.)
at the uollins Road colony, where predation was high,

the situation was different. There the nests nere situated

alese to the water level (65 cm.) in crotches of black willow.

 

 

105
This group of trees with the nests WAS surrounded by a dense
screen of sandbar tillow shrubs (Plate d, Fig. A). However,
because the area immediately below the trees was oxen, the
nests were access.tl: to avian gredators ard to animals that
could wade or swim in the shallow water. One 0? the nests,
which was partly torn down, could have been destroyed by a
dog or a fox. (This swamp was a portion of a much larger one
that afforded good cover.) sive young disegpeared from one
nest at a regular interval of one per day. Since the nest
was not disturbed and only one young was taken at a time, it
appeared to he the work of an aerial predator, or possibly
that of a snake.

among other mortality factors were infertility (six ger
cent) and broken or destroyed eggs (nine per cent), a total
of 15 per cent. while this figure is high, it is lower than
that reported by letersen and Young (19501475) s10 found on
average of 35 per cent.

One nest with yorng was deserted. This may have been
due to a combination of weather and interference by the inves-
tigator.

Death of young in the nest accounted for three ter cent
of the failures. No attempt was made to determine whether
death was due to a disease or some organic malfunction. It
became agparent in some cases, however, that the young des-

tined to die were losing out in the competition for food and

probably starved. T is was the case intzhe only nest with

 

 

 

106
six young. Although the last one hatched L38 normal size at
hatching (six grams) it mas small compared with the first
four hatched {14 and 18 grams) and died on the fourth day.
In another case, there the first—hatched in a rest of four

U

'oung died on the first day, ueath was rot due to competitior.
even though several nests cont ‘ned five yJ-xg, no more
than four fledged from any une rest. hither they died or
disappeared by some other means. In three rests one was
found dead. it is possible that three or four were of those
listed under predation by an unknown predator might have died
and were removed from the rest bv tie parents. ihe one that

u

dies is rot necessarily the last one hatched, although it

Out of 43 nestlings which were landed nine were telieved
to have been TOROVcd from the rest Ty the parent bird. nll
nine disap;eared from the rest within t4 hours after they
were banded. Those that disappeared varied in age from four

to seven days, most of them being five days. apparently the

I

\.

female, which is the one that cleans the nest, tries tc rero e

O
LJ
.1;
(D
"1‘

the leg hand. If the young have develoged the poner to

the bottom of the nest, they may escape vith only a broken

leg. (Three Lore found with broken le‘s at tie use of seven
£3 4 ’

eight, and nine days.) Younger restlirgs are probably carried
ahay and drOpped in the same runner that fecal sacs::re dis-

posed of. The writer did not observe any removals or find

any banded young vhich had been reaoved.

 

 

 

107

Pui“fllthl thire

Both parents play an important part in caring for the
young. Up to the time of hatching, the male's role has been
one of guarding his mete ard, to 3 lesser extent, the nesting
site. after the young hatch, he continues guarding and, in

"I

:1 feeding end nest sanita-

U)

addition, he sha:,s in the task
tion (removal of fecal sacs) throushout the period of rearing
the young. The female sperds a greater per oent of her time
at the nest, since she does all of the brioding, as yell as

,xurt c)? tlie freodiri . iltg: Mine d-evotwed L

care of their young.

Breeding. tor the first day 3r two a1 er the First ejj
hatches, the female follows a brooding rxvthr simila to that

. T 2“ a. ‘- : \ ‘ " ‘ ' - rv-r ‘fl - * H‘ '2 ~ 1" ". "’ "
folloyxa-«,iilng .I‘HJIHU1-'J lube -s -x)Lb at,»nutivc urn I’d the

,4.
L.
k ‘.
C‘
H
’)
'2
K

‘.

h"
Cr
Ho
’_ l
t .
F
”V

1
Po

‘1)
f‘.
Ha
F—
"S
:3

m

’ w " “u “ " .‘ ’ v -
COOLSI‘ 11;; It: 3: on") d J37 all“
‘_ , , . ., . '0 i . -i a. .' a \
tne turner tarts of the day. l: .,_n~x . ,-- -r A:

L. t

”a" "' ' - . "- -“ L .- ‘~ v w ‘ '1 (\ \ ',- ‘ . a. - ~‘.,
Moutucfl’xl ,ur;, s,mn,,;s.a oi¢i<:”.stc11 kl iturl tie fen

1 ~"3
" ‘ N c ‘I'. ' p ‘ ‘ ' ‘¥ \ . 1 ‘ ' . 1 ' V A I I
v1.61; 1- (eh-J . To.“ aim: 1r;— t , returns 1:1" u i'fwtlgtifx COV..'I : tie
.-, . . 4M ‘. A v-3 k1, n .' .-,, .1'.-. "
yuung. at rune fir :xCIi'mi:é~-. rai:L,.1ecebir:< t} '1':-
L \J

u - #‘- 0 l . ' ,- ,. . - , J. , 3 ‘
‘t“": at- ,‘ri.e (f Nest s has seen b0 Istirn , fl lkb Ex:
J— _ H I q 1 0 0

‘1 , 4 . , .- .- , - ."‘ ~ .-- - ----- ,
the LVL' LLJ UIIEG~€U§~LLI yxbLf. Urder this CerULLtLKCC

the brooding instinct was Treater thai that of feedirg bee v
Jrstead Cd“:feedirf,ifl,nt stéazhmiediatelgrinyvered them:;umfi held

the food for a few minutes before swalloming it. The female

n 1‘1' 4- c: ' .‘L , , fl .— ‘ ‘ I“. , . .. .-
‘V‘:¢ L 13‘-» N\’ w» U'tki \., \ \AI’.)1 .1 ’L( lit! (._ , LI-C I.r ) . .. ‘I u" ', I
y 0 1 ' fi In q . v ‘ ‘ I -, a '_ ‘- '-
..\32 air) t -LC' ii . tJ., ti' , (wzr-:¢d iii 1 «~v.ni tt<“n:j' 1.x J
.. ., ~.— - ,_‘. . A .-,+ T n .4—‘ - ..
. 2‘) L3 u»'.1.] rrc'v’:\. uhC Ly f1.‘-vt:f.‘:t f; .

‘ . ~ \ ‘ \ 1 .‘ r ‘ ‘ ’A I. r“ W r '1 . T N -. . . v- x m.
while CIUUCLHL, tie fen le -: Hieit onu tcnhltlub ft
.-, -..J. ‘ , , N -, . ,.‘ . . . '3 _ ,_ r A,, ~ “'1 -
hC'HAJE ern: “uvuw' rte c:oowf,1'9r ,JH. LL; th:;mivenii-ts LJ.'tLe

' 1\ t‘ . " V. ' I : c . I ' 4— .‘ ,. fl , ' ‘ ‘ . ' r. _ I
I] (- Ullé \‘ICI‘ xiv bk- }‘ (fJ- . ul-‘I -— Ev a ‘VCAre ~)f Ulr' ‘ I MAJ T: ~r L J "II-5 £‘1.‘\I’. (Kr.

Y
r‘
.4

his favorite perch near by.

freeiertlv, ‘8 they did durir" the ,uriod of ircubetier. Ohe

CL

Iesgonds to the sgvirr‘rw to“' s under her L, Chzngir; icr
.LOsitior or L” covering d flu” 1'..itfle le'd th-t Lo? 'Flted

out. Jhen the tem;ereture is kirk, she backs my end rests
partly on the edge of the rtst, thus ellowing air to circulate
over the young and, at the same time, sieltering them from

she fluff: her

C
F"
D-

the direct rays cf the sun. When it is e‘
f athers and settles down lCM in the rest so tfst only her

bill 'lui teil Efmwv.

as th; yowne er<x old ” erd the de' Put TCI 4‘ F325 t.e
end 01 n n~ the n:,t LVAOM’ gltotei. t}. ”apple Livrd‘ leis
t”d l to a” r I 1im ‘Jt<€:rg. hi,“ li'rt fours o” otserve-
tion at Rests C and t5 d rirg the first four days if rastlirg

life, it was found thet the fenele seent 5C yer cent 0? ter

43 :1

time on.the nest and 50 per Cent 0... Fy contrett it Me?

C
fr)

letrned fret 31 LOVE: 0? ‘lzeivetian at Vest L5, during tre
period from eight days until nest leaving, titt the femtle
Spent Only Fine yer cent of Le: time at tLe nest, six of vhieh

Wes for broodixg, and three per cent for elea.ing the nest.

 

 

fl . .
' I ‘. - - - ‘ - ‘ ~ ~ V‘rfi,‘ — '1 .1 . ' V'l ur‘ w. u u
' ' fl - 3" u‘.‘ ' ‘Y‘ ‘ (J ‘ -. - . I . l
4 LlJ.-'. cu u L U'gil .’ '. I... v.- \J a" Lfla'_l I ...-~ .1 ‘e IJ gar. .:\I V1 . Ant) L1". A k. '-“"v’
‘

gtriods and st the ‘Gglhfili‘ thd 3nd of night

r‘l
H
,;
\
n
U
Cb
F '°
:1

(3.",
0

Female of Nest 55 erLGeC tht young at Light rntil they ell

left the nest.

Feeding. The parents share in feeding the young (Tables
XV and XVI). In 34 hours of otservetion tie over qe 'm"ler
of feeding visits made by the ferele was 5.3 her hour (ex-
treses O and u}; the isle ave? fed ;.5 visit? my four {ex—
tremes 0 end 5). During the first five days after hetehihg,

-‘

when the female stent much of her tine brooding, she made 1.1
trips per hour, while at the same time, the rule made 3.5
visits per hour. letter, when the yawn; ‘tere eight days. old
or-older, the female increased LGTS to 4.1 times per henr,
tut the male @enreesed his to ¢.5 ter heur. he combined
efforts of hoth tsrents ranged from four to seven visits rer

hour throughout the life of the nestlings.

t:)

m
)

o. the lRTBRtS of Nest t5 ire

FA.

The feeding freon-she
deiieted gr34hirelly by Figs. 15, l6, l7, and 16. The first
three greyhs are based on seven o‘servstiens nede on three
consecutiVe days (when the young were 8, 9, end 10 da's old,
resyeetively) and represent n little twee Us isms. A? abs 3-
vation. Combining these obser'qticns, an averngr fee

I‘

frequency oi the male, femsle, and both was drawn in Lia. 18
to show the approximate picture of feeding throughout an en—

tire day.

 

 

llO

 

 

 

 

 

4 5 6 7 8 9 10 ll it 1 Z 3 4 5 6 7 8 9
15’} I I I I I I I I I I I I I I I I I 15
14' -‘“—”—‘ Mole -14
i2” ----- Female 'i:
11. Both -ll
10- —10
9- — 9
a) 8— J 8
fl 7— - 7
U) 6 _ 6
'3 5— J 5
no 4- -{ 4
,5 5- % 5
U 2 B
8 l: 1 l
H 0"1 1 1 1 1 1 1 l 1 1 1 1 1 1 .4: O
4 5 6 7 8 9 10 ll 12 l B 5 7 8 9

 

Time of Day

Fig. 15.

(Lornirg

Feeding frequency of bronzed grnchles at Rec,
25 with four nestlings eight and nine days old.

obserVetion was from 4za5 to lO:40,and the afternoon obser-

vation wee

from 3:15 to 6:50, hay 39, lQSz.)
4 5 6 7 8 9 10 ll letl L 3 4 5 Q 7 8 9
15b T I I I I I r I I T 7 I I I I I ['15
14' -—-—-- hale '14
if' ————— Female “i?
“’ Both ‘ “
11- ///~_‘ all
10- ~10
9- - 9
'3 6- ’ ‘\ 4 6
'2 5- ____//‘.x ‘\\ - 5
{a 4- \\ ____ . — 4
g 5- \ —~~><;:::. ‘ 3
’U 3- - 2
3 1- - l
h‘ 011 L 1 1 1 1 l I 1 1 1 1 1 1 I 1 l l- O
4 5 6 7 E 9 10 ll 1% l 3 3 4 5 6 7 E 9
Time of Day
Fig. 16. Feeding frequency of bronzed grecklee = Neet

35 with four nestlings nine and ten days old.

 

 

 

 

Ufiorning

observation was from 5:20 to 8:40,and the afternoon obser-

vation woe

from 11:00 to Zzto, hay 50, 195L.)

U

 

 

 

 

 

 

 

 

4 5 6 7 8 9 1C 11 15 1 :1 5 4 6 E 7 E 9
15...! I 7 T I T T I [fir I I Ifi I I 15
14‘ —‘—° — kale ‘14
13 ------ Female ’13
lZP B -l£
11- 0th -11
10- -10
g- - 9
m g” g
+2 _
‘3 6» c
«H
,, 5} 5
1m 4~ 4
f3 5- 3
('33 2" 23
a) 1' g
In 0% I l I I l L I I I I l
4 5 6 7 6 9 1C 11 12 1 2 3
Time of Day
Fig. 17.

25 with three nestlings
10 and 11 days.
afternoon observation was

May 51, 1952.

Feeding frequency of bronzed grackles a

and one fledgling near by. “gee were
Morning observation was from 5:15 to 9:z5,
from 5:40 to 5:15 and 6:15 to 8:30,
(Uircled toints are estimated.)

+ \I. (_‘ L
,.

Kr. ¢ I II

J.

J

 

 

 

 

‘4 5 6 7 8 9 10 11 12 1 8 3 4 5 6 77 E 9
‘15—. I I I I I —I I I I I I I I T T I T-ls
14- —— —~—— hale -14
13_ —————— hemale -13
16- both -1;
11- _ 1
10. -1O
9— ~ 9
:3 BF A - 8
b /\ I _ 7
I; 6" [IP\\\ . I, \‘ ‘ ' 6
mi 5- I ___ / \ /\ - 5
:> 4 I \\\ 0’ \\ fl . \ 4
m ' / “ \ ‘
.5 3" ’/'/\‘\ / \.\ \-- A» A\_ -/'/’\\\ / \ - 3
U 2- I ‘\ /'e"— *‘ _ \“"‘\'°- -/-'-,7 ‘\'7l“\\ " 2
8 1". I, \‘ , __ l
3* 0' 1 1 1 1 1 1 1 1 1, 1 1\¥1 1 1 1 L, 14 O
4 5 6 7 8 9 10 11 12 1 3 3 4 5 6 7 E 9
Time of Day
Fig. 18. average feeding frequency of bronzed grsckles at

Nest 25 with four young during the last three days before leav-

ing the nest.

It represents the average of the total feedings

by both male and female as shown in Figs. 15, 16, and 17,8 total

of 25 hours of

observations made key 29, 30, and 31, 1952.

(Circled points are estimated.)

 

Feeding hy both the mtls uni the female follows a ytt-

tern Of attentive and iLatteLtive geriod . "broughcut the
day there are five periods when they visit the rust more

r+

o
I.“

‘7'
va-A'rr

- 'r
\J

frequently (8 to 11 tines by toth), the fireatcst amcun
in the first half of the day. Very soon after the male ar-
riVes from the roost, he terlns the feeding of the young for
the day. Between the hours of 4:40 and 5:50 n.1. both par—
ents are highly attentive. “fter a Lericd of about an hour

.0

01 less frequent visits, they again become more attentive
between 7:00 and 8:30 A.1. n third puriod of attentiveness,
which equals the earlier ones, occurs between 10:00 and 11:00
AJN. From that time until 5:00 I.m. the feeding frequency is
at a moderate rate with the lowest period occurring between

8:00 and 4:00'P.h. As night approaches, they become more at-

C

C)

tentive again. A fourth peak of activity occurs tatween 5:
and 6:00 P.M., and the lest teak (mostly by the male} is be-
tween 7:00 and 8:00 P.L. Since the female begins brooding

between 7:50 and 8:00, it is the male d;et comglstes the feed-

rr
U’
(D
c ‘f
(f,
(D
t“

ing for the day. The last fetjing usutlly recur“
8:00 and 8:15 P.t., just prior to the male's departure for
the roost.

The impulse to brirg food to the nest began early in the
case of the mole of Nest 6. It has already been pointed out
that he fed the female at the nest «s early as the sixth day

s may he regarded as "courtship feeding";

H.

of incubation. Th

however, such an act was never observed between a male and

 

 

113

female away from the nest. 0n hay l7 at 3:20 n.k. there mere

1

two young, which had hatched during the night (the down Was
dry), {U31 two ngz‘s greecnfl: in N:£t Cu lrurirg thzdrwxct two
hours the male came to the nest thrge times with foo3, and
the female begged for it and was fld by his. he young were

not fed during the two hours.

The method of feeding is direct, that is, food is car-
ried in the hi1 and Llaced in the throat of the nestling
(Plate 10, Fig. A). The number of young fed at a time Varies
according to tie guantity of food. If tto large srubs are
brought to the nest, only two birds are fed. Usually the
male has a larger amount of food per trig than the ferale so
that he usually feeds three or four young to her two or
three. Food is apportioned according to the intensity of heg-

ging on the part of the young and according to whether they

can swallow it cr not. If they do not shallow it, after it

I—‘t

'

s deaced im;‘m1eir thrwm ts, it 2.: ramoVei Jr) :1t i-f i1114_~
throat of another. By this method each nestling receives
food from three to fiVe times per hour.

If the fenale is brooding, both tarents occasionally
feed the young at the same time. Cooperative feeding was ch-
served at Nest 25 on several occasions. The male, on return-
ing with food, usually went first to a high perch in a dead
tree located only a few feet from the nest ng site (Plate 10,
Fig. B) and generally announced his arrival with a "check"

or a call note. The female could see him from her position

 

114
on the rest. On three different occasions she'res observed
giving a signal to the sale, which began with a begging
"whiney" note followed by four 3r five poirting and Towing
movements. The vale responded by arriving immediately, usu-
ally in silence or with a "check" note. Upon his arrival she
perched on the edge of the ncst facing him and begged with
fluttering wings and a "whiney" DJtG. He usually gave her
some of the food; then both proceeded with the feeding of

the young.

Nest sanitation. The nest is hett free from excreta

F1

and other things foreign to it by both parents. ihe wale's
part in the sanitation cf the nest is mostly that of removing
fecal sacs. The female not only removes fecal sacs but also
clea.s the nest below the young (Plate ll, Figs. n and B3.
Several times, usually in the morning following the first
or second peak of feeding cctivity, the female of Nest 55
was observed to be half buried below the young for nearly a
minute at a time, ticking and eating drorgings from the pre-
vious night. These morning cleaning periods were from three
to eight minutes in length. as indicated heretofore, it is
believed that young which are tended before they ore csgable
of clutching the nest lining securely are sometines removed
by the female in an attempt to discard the band. Older nest-
lings, as has been pointed out, clutch the nest lining tight

enough so that they are not removed, but in a few cases may

receive a broken leg as a result.

 

 

On the average, one fecal sac is removai by a parent on
every second visit to the he:*. after each leedihr the ;ar—
ent bird looks for and often pauses for a fecal sac. if two
or more appear at one tine, the farent may eat one or .14,

The maximum nuater observed removed at one time was three, wnd
all three were eaten. Both parents eat alout as many as they
carry away. The male removed a fem more than the female
throughout 54 hours of otservation. Those which are carried
away are dropped in about the same place by the same parent.
For example, the male of Nest L5 was seen to carry them about
25 meters away and drop them. Two or three disposal spots
were found at Trowbridge harsh during the first year of study.
The female was not observed to drop those which she carried
away, although she could have either drop; ed them or eaten

them.

')

befensc. Defer . of the nesting site,and the rate by

rd
(
k

‘

the male is by vocal objection, by guardihg, or by cirect
attack. One of the reasons why he maxes fewer feeding visits
to the nest, especially in he last few days before nest
leaving is that much of his time is occupied bv sentinel dutv.
The male of Nest 55 pe~ched much of the time in the upper part
of a dead tree located near the nest (Plate 10, Tig. B). But
he a so used another dead tree near the railroad tracks lo-

cated 50 to 75 meters north of the nest, or a willow tree at

the south edge of the marsh. If the writer stepped from the

 

lld
blind when the Kale was on any of these sentinel perches he
would impediately come to the nesting site and object by
"churrs" and ”checks." When other birds, such as hawks or
crows one to the marsh, all the red-wings and greckles sive
Warning notes. That of the red—wing is a kind of whistle Put
that of the grackle sounds like ”ks—u-u,” which is bu7zy and
slurred downward.

Guarding the female has already been descrihed. lt is

the same during the restling stage a

(0

it is during the incu—
bation period.

Direct attack is used only as an extreme measure of
defense. AVidn enemies are chased ly the male grackles and
sometimes‘attacked in flight. ouch attacks are hot fetal.

then the young are n,arly ready to fledge, the parent tirds

are extra sensitive to the presence of an intruder. 59::-
silnrxlly'-u.iale,(‘r f;n;lxr;vade sfll 'tt AH; fli.13,t'o six: 31%

investigator, tut at no time did they actually strike.

The female'srmflmod of defenseifl:t}e samea; tmst of

(0

the male except that she does not guard or act as a sentinel.
when there are young in the nest, her greatest concern s ems
to be to cover them, as shown hy the IrOtGCtiVo action of the
female of Nest 35. One afternoon, when the young were 9 and
10 days old, the glacklcs and red-wings made warning sounds
that usually indicated the presence of an avian enemy. The

female of Nest a5 immediately arrived and covered the young

by drawing well down into the nest and spreading her wings

 

 

 

ll?
slightly. The effectiVeness of such frotectlon is anesticn-
able. It may have been under just such circumstances thvt the
female of Nest Ll (page l04) lost some of her tail fenthe
The only trace of the young, which were 9 and 10 days old,

was some feathers in the nest. If this was the case, cover-

I.~ A. (as,

H.
r-

Ig the young was rot an effective means of protection.

 

 

 

 

POSK—NESTING ACTIVITIES

Young graokles depend upon their parents entirely or in
part for their food during the first five or six weeks after
they leave the nest. The dependent stage is three to four
weeks in length and the senzi—dejonwznf" stage i" one rr two
weeks longer.

For the first two days after nest leaving the young
remain within 15 to 20 meters of the nest. Because the

flight featheis of the wing are only a little over half

grown and the tail is less than one-fourth developed, loco-

:-"

motion is a comb nation of jumpin: and climbing, aided by

fluttering the winés to maintain balance. Three to four
days after leaving the nest they are aHle to fly unsteadily
for a distance of 50 to 50 meters. When they have attained
this degree of ability to fly, the family leaves the nesting
area. Small family groups of two adults with youné may be
seen feedirg on lawns and flying about throughout the first
half of summer. At East Lansiig they were seen as late as

the middle of August. They fly t roost together as soon as

(1

the young are capable of sustained flight. According to
Jones (1897) the old males escorted the most forward young
to the roost as soon as they were able to fly, or, if the
whole brood developed at the same time, then the were es-

corted by both parents. In this region young grackles were

"seen.a.t the roost during the last week of June in 1952.

119
For the first two or three days, at least, after the

'young leave the nest, the frequency Cf fe

t’ 1‘

:ditn; then: ccr1tin~

use in about the same rhythm as was followed while they were
still in the nest. (Since observations of the family activ-
ities were not continued after they left the nesting area,

the feedin¢ frequency was not obtained.) As soon a“ the

Q . Q

youn; leave the nest, they give the double-noted "location”

a

call, which was described orcviously. On the d'“v when mos‘

( l
d .I

of them fledge, the marsh fairly pulsates with the incessant

calling of the young. Red-wins fledglinys when present,

Q 3

I v.

=1 ,‘
8'“. Q thc‘

r hi

F“
(+
3
;.
‘.'
J
T‘
V

ohorrs, too.
Care of the young now consists of feeding and protect-

ing them. The young continue to.he fei ty the parents lonw

D

after they leave the marsh. On July 51, 1951 a male was

seen feeding a full grown youni, while the latter begged

L;\/

With Wing fluttering. On August 4, 1955 an adult female W“

fi
VI (ks)

ITYllovn;d 13: 'KI; fo=u13 ’ri a. L Tr1 in ‘b331mfl1 31‘ foami. "1a“
.. ‘ P, 1’ - _ ~ 0 A H . . Y“ I.
Save a bthy double note (a nodificaticn of tie 1003610“

call note) as they searched for food and followed the narent.

~14

'\

AS the female fed them, they begged in the 118113] manner.

however, 1y this age they were able to catch insects, turn
over leaves, etc., while heir parent was hunting food for

them. They had nearly reached the stage of independence.

 

 

 

120

HAIJLHELRED "GUNS

Three young grackles were reared in a cage from Kay IS,
1&52 to August 10, 1953. Two of the young were fled lin:s,
which flushed from ihe nest at the tine they were taken.
They were estimated to be ll days old. Later they eroved
to be females. A third yonné was estimated to he 2i ht daws
old at the time it was taken. Its adult plumaie late‘ was
that of a male. At first they were housed in a small cage
which was one by one by one—half meters. In mid—$2;
they were transferred to a larger caye measuring one by one
by one meters. The followin5 Spring, in mid-May, two of
them were placed in a large out—door caJe measuring two by
two by one and a half meters. (The third grackle, a female,
had been killed by the others earlier in the spring.) This
cage was enclosed with one—inch chicks fCLCiné and was with—

H’n

out a floor. in;

development of plumage, voice, and feeding

,

habits, and of motor actions and responses was observet.
drowih

Even thouvh these three oun* trackles were in an un—
b bi.)

natural environment, their growth and development revealed

some information regarding the probable developmental

changes of young in the natural state.

 

[assurewerts such as those made of ra silir=s were also
mad, of tho hand-rearof birds. The writer ardenvtrcd to
food the young regularly at 45-minute intervals but often
was not able to feed them for intervals as long as an hour

and a half. Growth in weight fluctuated frc n dz' to dav ac—

L
cording to the numter of times they were fed in a day.

Fig. 19 QlVCS a DPPpth picture of the amour t of'Qrowth.in
weight and in the len; th of the bill, wing, and tarsus. It
Will be noted that gro'th in the lens tn of the hill, under
conditions of captivity, did not amount to much for the o—
leven days following "nest leaviny." After the two females
were full grown (50 to 40 days old) the bill measured 27
millimeters. The tarsus grew to the maxinin length of 31
millimeters. :tpptrently the tarsus does not grow 5'11301’1 more
than about two millimeters after the Wound have rcat ched the
fledélin; age, sinc cc it avera.; es nearly 30 millimeters just
before they flodye. Because the win; feathers grow a least
a few millimeters each day, they are a fairly reliable cri—
terion of age.

Although measurements were not made after ll days of
cantivity, it became apparent that the voun Oest one was des-
tined to be a larger bird. Before its juvenal plumage was
Completely develOped, its feet, less and bill appeared lary-
er than those of the two females. Later, when all three
were in adult plumage, it was obvious that the youngest was

8 male.

 

 

 

 

8 9 10 11 lb 13 14 15 16 17 18 19 20 pl L;
115i? r ' I . I r u I 1 I I u I+115
110- weight ,”"”‘ -110

---- bill length l/
105- _____ Wing H [I ‘105
‘—"——- tarsus " I,

100- //, ‘100
95" /,/” -95
90 ‘90
85 -85
80 -80
75 -75
70 -70

33 65 _65
o

.3 60 60
E

W1

:1 55 _55
-a

E 50 _50
a

0H I

A: 45—, fi45
E?)

C: 40" -40
o

*4 35- ‘35
E O~°~°

“3 /

:0 25-./° -25
.3 20- {do
2 !‘°"0000°000003.'.‘. """""""""

no 15'— o 0.0. ".;°.';...°...‘.‘. ....‘ . ~...‘.,. 415
'3 0. . ‘.000

*5 10- O

 

 

 

ilkJILLLfilL$IL1
8 9 10 ll 12 l5 l4 15 16 17 18 19 20 81 2

Age in bays

Fig. 19. Daily amount of growth

grackles kept in captivity.

Light lines

of young bronzed
represent

average of two females, while heavy lines show measure-
ments for one male.

 

 

 

125

(Mmel plumage is acquired by a cosplete postnatal
mclt (Dwight, 1900:1663). As the ,juvenal plumage feathers
grow out, the down feathers are carrried away from the body
andvmrncfif by the seventeenth day. Juvenal plumage begins
wifiitM3appearance of the pin feathers of the primaries at
thaagccfl‘two days and is complete when the rectrices have
attained hill SifiK? (25 to E£)cbrvs after>luitchin3). The au-
rimhhu'region 's the last to have pin feathers and these
develop into feathers by the nineteenth day.
Dwight (1900:167) described the juvenal plumage of the
purple grackle, which he said was indistinguishable from

that of the bronzed Srackle, as follows:

. . Whole plumame dull clover-brown, the body feathers

‘ Q
often faintly sages With paler brown. Tail darker with
ourgCLISn tints. sill -nd SJot so ld-h'TWh, black when
)1dkfl“.
\ Y)‘: 71' - 5-1 , -° 7 q _ w 'v ".‘4 3 ”.f‘ War}! 3“ CV‘ ,2 ' ~. "-17 3 ‘ > " d
37;. Cs. lllo u-A1Cz i])\ 61.3.]. ;.)..L\U.ls«(~)'~.. f..- ...C~.LL/..) ~xl.\..« l «. .k.~.L€/S [16» flu te

at 'VIn ,hivenal dress the female is perhaps paler below
m is the male and usually indistinctly Streaked." A11
es: 017 tflie hand-reared birds in this study showed a faint
ealcirng can the breast feathers. It was first observed on
ssisctmeorsth day for the females and on the seventeenth day
the me. la.

Tine gjostjuvenal molt, which began about the first week

1115] zarui ended in late July, was complete. Upon examin-

ten specimens of juvenal graclcles collected in the field

124

itvmsibund that melting began in late July and ended in

ndddmmst. According to DWléht it takes place in early

IWth. The first winter plumage, which is acquired with

He mmtjuvenal molt, is identical.ix>‘flm3 adult's plumage.

Themewfllic hues about the head end neck and the bronze

as described in the section

color of the back are the same .
irst tauntial

w

(malhm;with taxonomy and nomenclature. The
plwmue, according to Dwidht (1900:168), is ". . . acquired
byxwmr which produces no noticeable effect as is regularly
lne postnuptial molt

thecmse with iridescent plumaées."

tmgan July 12, 1953, when the first wing feathers appeared

in the cage. At the time the second female died (August 6)

and four days later when the male was released, this molt

was not yet completed.

fig we 'r
PGGanb

Foq~ the first three months all three young were fed a

ixturwa of‘cooked cornmeal and Cth“ed, boiled egg (includ-
Forceps

ng ttma shell) with a drop of multi-vitamins added.
re lisexd to place the food in the Open mouths. The tongu

stuapeud like an arrowhead with the posterior part of the
nguea Ikorming the two barbs. As soon as food is placed be-

;d. tflsc:3e barbs, the swallowing reflex causes

thus pushing the barbs against the food. Sev-

rwetneaczt,

1. sxnc<3essive contractions of the tongue are used to push

:fcmpd. to a point where it can be swallowed.

 

 

Hunger caused the yound to beg. At first the male,
vflaich.was three days younger than the females, begged by
eaxtending the neck upward, and Vibrating the head vigorously
vflnile he uttered a "screechy" peep with his mouth wide open.

0

The females opened their bills, uttered a raspy be.”

{30 no;
sound.and fluttered their wings. They did not stretch their
necks or vibrate their heads. The male changed to this type
of begging a few days later. When they were 18 days old,
they begged as described but added a few bows. Bowing was a
gesture revealing eafierness to have the food plaCLd in their
tnouths. One was seen wiping food from its bill on the four-
teenth.day. They were entirely dependent for feeding until
near the end of June (nearly two months old), at which time
they began picking at the food and taking it from the for-
ceps or fingers.

In addition to their regular fare other types of food
were offered to the birds in order to see what they would
eat. They were given a variety of insects, grubs, and worms,
which they ate. The grubs had to be killed first before
they would take them. They did not eat strawberries or cher-
ries when these fruits were in season, although adults rel—
ish them.

After the your; were in their winter plumage, they were

able to eat dried grains. The palatal ridge (des ribed on

page 134) was used for cracking large kernels or seeds.

 

 

The male was not heard to give the "location" call note
at any time. His beyging ”chirps" were modification of it,
but this did not sound quite like the notes uttered rhyth-
mically by the females during the first few days of captiv—

ity. A few days after the winter plumage was fully devel-

oped (July 15) the male attempted to sin: for the first

time. The "song" consisted of a series of unnusical "gur-
gles" and "Jaréles." The females did not attempt to sing

until later. Their vocal sounds were limited to "checks"

and "churrs" of tr

(I)

adult typo. Late in December all three
began singind. The son; consisted of three syllables. The
first two were an abrupt "check—check" followed by a pro-
longed buzzy note. This was accompanied by a puffing move-
ment of the feathers typical of an adult song or call. The
voice of the male and of one female was of the same “itch
and quality. The buzzy note of the other female's son; was
shortened and pitched lower. Early in January this same
female uttered the "whiney" note and yostured a few times.
As spring approached, begging on the part of the females
was more common. The full adult song was never attained by

either the male or the females during this study.

(1..
H
(0
(E)
n)
f—o
:3
(J .

On the night of the first day in captivity ll-day-old

fledglings (females) were seen to sleep in two ways: one

 

127

tucked its head under the bend of its Wiu' as it sat on the
floor of the cage; the other merely drew its head lack with
1 pointed upward at a 45-dogree angle. As soon as

they used a perch, all three tucked their heads under their

Lest-Building Urée

On May 27, about 10 days after the male and female were
placed in the outdoor cage, the female showed sipns of want-
in5 to build a nest. Although she picked up pieces of
string, sticks, ;nd other materials, she did not attempt to
form a nest. Instead she flew from the ground to the perch
or to an upper corner of the cage with a piece of naterial,
became discouraged and dropped it. itis jom=ie r-r seen
posturing before the sinping male, out copulation was never

'1 -\ "
. br'm t-

LA,

observe

5)
f- O
O)
P
d-
C.)
O/j
i
(D
,3
9
LJ
3.)
(1
V.
,L
O
i
{—1.
'7
.—-§
\
L
p-
3
1.4
'3
\O
,Q
C

least, is ready to attempt a nest the

 

FOOD AND FEEDiIG HHZITO

The n so outstandins published work concerning the fin

{)1

OJ. graclcles is that of deal (lOOO), which was based on the

analysis CL the s'cmach contents of 2,346 purple grackle

(including the bronzed crackle). Included with these were
45C nestlings. Those birds were collected at all seasons

of the year and from all parts of their range. Rare recent-

./

‘1

ly Hamilton (1951) published a study of the food of nestling
bronzed grackles, which was based on the stomach analyses
of 130 specimens.

Because so mrch has been contributed by others to our
knowledge of food and feeding habits of this species, the
writer made only a cursory examination of this phase of the
life cycle. The aim here is to present some facts already
published by others and to report the results of the personal

findings.

Food

in feeding is as 'reat

L)

L)

The adaptability of this specie
as in nesting. The list of foods that it eats is loud End
varied. Beal (1900:50) found that the year—around diet in—
cluded, on the average, 30.5 per cent animal food and 60.7
per cent plant food. The ratio of the amount of animal and

Plant food varied with availability. For example, during

 

fSeasonal variation of animal and p ant ford is more clea rlv

the fall, Winter, and early spring, when insects w;ro not

A, _ 4 r: . ~¢ - ‘lt‘ ”-17‘ r. «A . L «1 -- " . .us
n1uner%N1s, one «licrt c1 -.n: gzcwc hie \«snsigs'mmi l_1r :siJ o1 ra;1es

,1 , g, .- a" ,‘ -°,.
and seeds, and duri n~ the snmher $3152“, particularl, airihb

U
tie breeding season, heir food was mainly animal matter. /i’
shown by the quan tity of their favorite 1‘
insects and corn. D11r win the winter (February) Beal found
less than three oer cent insects in their diet and '32 oer

COT]

Spring (march) he found lC oer cent in—

cf
0
C)
"3
'1‘
H
:3
(I)
£0
'3
1“:

o
B
E“;
5
a

sects and th 3 increased to 62 per cent by May. Th

'\

of corn eaten during that period deoreaseo steadily to about
7.7 per cent in flay. During summer the in ect intcke was
62 per cent and that of corn remained about the same (?.7

per cent) until August when it was increased to 14 per cent.

This late summer increase is probatly due to eating corn

" . ‘ . " n r _ v- - .~ ». . a. 1"
111 tne Allxu [us cold ueafiflnn? QPJPCakJK%J, the nu;m~er i
insects available for food decreased and, at the same time,

wastes of harves ed corn were plentiful; conseqrertly, the
raufuer of insects eaten deo1waa s11 to l: p r cent (Catcher),
While corn increased to 50 per cent (Sentenoer). Animal and

vegetable foods of grackles reported t7 Bea] are given in

 

Food of nestlings. Peal examined the stomach conte Ht
of 456 nest i153, ran ;ing in age from one day to near the

fledgling stage. The overall proportion of animal food aas

 

150

74 per cent and of plant food, 20 per cent. However, birds
less than one week old had nearly all animal material, 95
per cent of which was insects. Most of these insects were
soft-bodied forms, such as beetle larvae. Older estlian
received about the same diet of insects as that of adults,
which included adult forms of beetles as well as the grubs.
List IV shows the stomach contents of nestlings as renorted
by Beal.

Hamilton (1951), in examining the stomachs of 130 nest—
ling bronzed grackles in New York State, found the contents
'to be composed of 39.1 per cent animal raterial, and 6.4 per
cent plant material, the remainder being inorganic matter.
(List IV)

Spiders were found more frequently in the stomachs of
small nestlings than in older ones. K few millipedes were
also found. Earthworms were broken into fra5ments and fed /
to young. Digestion of them was complete—~there were no
setae present in the droppings. A few sowbugs and snail
shells were present.

The remains of small vertebrates included red-backed

salamanders, Plethodon cinereus, tadpoles of Rana clamitans,

 

 

 

and alewife, Pomolobus pseudo—harengus. One six-dav—old

 

nestlinn ha‘ a newborn field mouse Microtus oennsvlvanicus,
3 L .1

Q

 

in its stomach. Fragments of what was probably a masked

shrew, Sorex cinereus, were also found.

 

 

131

- 0*

Plfult fCLAl was; fourmi by tfiuniltafll to lmz;freserrt 1I;.x;

‘- — . \ I r-, " I" \' ~ I ‘ .
oer cent of the nestlin s' st-naCns. Ufewu rass was in

l ‘ .J

several (nine per cent) of the QiZZfiPdS. Other vegetable
material included some waste grain and a few fruit seeis.

Stomach anal sis of East Lansinr ”racklos. seven nest—
i __ 11 L;

 

 

lings nd 14 juvenals and adults were collected in the East
Lansing area. The nestlings, ran in; in age from the day of
hatching to eight days old, were taken from the Trowhridge
Marsh colony in 1951. The older specimens were collc?ted
in a blueberry swamo four miles east of East Lansing during
August, 1952

The corte11 s of each Sizsard were sorted into vegetable,
animal, and twin ral materials, and the per cent of the tc*a1
volume was determined for each. In the case of the nestlings
he stomach co Hen .) were nearly 100 per cent axin'l remains.
There was a trace of mineral matter in three. To plant fl"—

terial was found. Stomachs of the juvenal and adult Eirds

contained 40 oer cent animal remairs (e" renes, 15 rad Ed).
53 per cent plant material (extre ewes, 15 1nd 9%), and tWC
per cent mineral matter (extremes, trace t five).

sted 8]flWM“t entirel" of’

L.

The food of the nestlings Hon
insects, but a few spiders and smell crustaceans (oravf1sh)
Were also included. There was no trace of plant material
Such as seeds, fraéments of leaves or stems. hineral mat

Was found in the two older nestlings.

 

 

152
Because the juvenal and adult L“wuk1:S were collected
in a blueber“; swamn at the time when there was an atmrdance
of berries, the ner cent of vehetu¥le matter was Li her than
that of the animal matter. Even tron h ‘he 'raekles ate
many berries, :hey also fed around the margins of nools in

the swamp, where they found insects and small toads. List V

includes the animal, vegetable, “:1 cinefal nat=_ia'” Iran?
in the filZZRPdS.
Feeding Habits
The adaptability of grackles is lso exeresssd in their

feeding habits. The structure and use of the till ccmhire
to a certain degree some of the features of both insect—

and seed—eating birds. This, in addition to

a natural re-

sourcefulness, has caused the northern “reckles to enter i“—

O ..A
to a larse number of feeding niches from which they 5et a

variety of foods. According to Beecher (1951‘129) the rrack-

\J

les of the genrs Quiscalus probably head the list, in so far

 

as adaptations for food in the blackbirds are concerned

Structure and use of the hill. The nearly omnivorous

diet of this species requires a hill which is capahle of
catching and devourinJ insects, as well as nickfing no hard
seeds and nuts and cracking them into pieces small eneu;h to

be swallowed. Certain structural features of the hill nit

in securing both types of food. In his account of the mus-

 

cular and skeletal adaptations

Beecher (1951:419) pointed out

isle (:f inevijig lflie tfiTfOI’IHfllMllblCBIIT one o

the commissure. He described the kin- ti

dible as follows:

rf the sku

11 for getting

0

the fact that tirds are

‘

r»

‘03

C'lu‘v" Tl V! i th P e S p F.)

of the toner

st to

man-

. . . the upper .andible may be moved no and down on its

articulation ‘ith the cranial part
4

11330- iinmntal h n

5.)
l

is communicated e; an articulated series of rod—like
elements to a quadrate bone

&

In use the upper mandible is p:

of the s.alll--th
e- —and that this movement of the b

on either side of the s

the low r mandible is depressed, and is

downward) when the lower mandible is raisw

fective means of increasing the

the axis of the bill. . ." (39

per mandible were not movable,

The a:.is of the bill we ul 5
gagre . . . , EHld ifliis woul.d
sycc1es rwrnlired rm) ria tch
precisely these forms tl at
skull novennn

By comparinz, the cowbird

laius, and the rusty blackbird,

gape and

eoher, 19

1 ,
then 1:830};

chanpe with the degis

he hard<s

13:ir nrxg'cpiickly.
11(1‘J’3 (Jhe lli

Kolothrus,

 

Elnlw 5:13

0
ill

my ved upward) when

512412). If the

er notes that

-e
t on insecti
l
n.

She s t de

JP
the red-win ;,

1

Beec.er founc

correlation between the amount of movement cf the unper

dible and the diet. The movability of the

was greatest in Euoharus, which

M

cent) than seeds (47 ner cent),

Which eats more seeds (77.7 per

etracted (moved

eats more insects (F 5 her

and less movable in Hol

othrus

 

cent) tr an insects (22.

5 per

cent). The bronzed grackle has a bill more like that of

Agelaius, that is, more slender

and a more movable unper

 

 

154

rmandilale 'tharn thafchf lkxiotlwris. Its (lint, €18 lVlS aljuyady

 

..

cut, consists of 30.3 eer cert animal material

I).

been nointe

r
.-

V

and 69.7 per cert Cf nlant material (Real, 1903), slithly

more irsectivorrus than that r? lelothrws.

.4»

 

Besides havir' a kill fairly well adagted to catchin
insects it has another Special structure which aids in the
crackin; of hard seeds and nutshells. Wetmore (1919:100,
191) clearly described this structure as follows:

The crrieus nael-like, angular projection found on the
palate in the North American Gracklcs of the nenus Quis—
calus [is] recopnized as one of the prominent Characters

distinguishing that group of Blackbirds . . . the pala-
tal keel is developed as a compressed nrojecticn from

O

the rocf oi the mouth sliéhtly behind the center of the
cemmissure. Viewed from the side it is truncated in
front, forming an angular projection that has a tendency
to become toothed at the tip. The anterior narQin is
sharp and the festerior portion is thicker and stronger.
The entire ridge is dovelnned as a fold in the horny
sheathing of the nalate, and the surface of the premax-
illa underneath is smooth and flat and with no indica-
tion of a bony ridge to supefrt the Peel.

accordirg tc Wetmcre this ridge ijSt apeears when the your;
are Ineady ix: lea‘wa the rnw3. arxl is ilfilly ~u urn bj' 11: time
the j1rweual_s:ta e 513 reafflred. the

be true of the hand-reared birds in this study.

The nalatal

as

*5

.‘ 4" ' r r‘ ' 4“ ' ‘
1dqe is used tc cracl Lernels oi corn and

‘

to score the sqel

l
A—

s Cf acorns in such a way that the shells
are cracked off, thus eXposing the nut meat (Wetmore, 1919;
Schorger, 1941). In this way the more slender bill of the

grackle can do what the thicker bill of Holothrus and the

 

seed—eating finches are able to do.

 

 

155
uapin; is another method of usin; the bill in search of

food. Beeches (1951) desccihcd the manner it which the east—

. J

ern Meadowlar”

a
I}

may well fit such a fcod-searching method used b" JPRCPlOS.

Of this he said ". . . These lirds drive the closed bill ir-

L

to the ground and open it powerfully “-ainst the resistance

' .2 V

of the earth." European starlin 8

Ag) ,

Sturnus vulgaris, bore

 

holes in lawns for ,rubs in the some manner.

During eart of the study made by the writer two bronzed
grackles were kept in captivity in a large cage which was
open at the bottom. This Cude was placed on a lawn that was
infested with white grubs. Starlings foraged there every
morning, leaving the lawn punctured with holes formed in the
manner described by Beecher. The writer roted similar fresh—

ly made holes in the :round within the confines of the

grackles' cage, which were not present before. (Starlings

COUld.IK‘t enter"mr3 cage, sijmra it was cxrwered wifdizi one-

inch mesh chicken wire.) Even thou.h these raohles were

not observed formin; the holes, it is believed that they
made them by gapinQ, since the holes were so simil(r ir
shape and death to those formed by starlings in the same
1 awn .

Use of the feet. As eemnared with the use of tha rill,

 

grackles use their feet much less during feedinb. The: sel-
dom use them to uncover food by scratching. The bill is

used to turn over leaves and rubbish. The feet are employed

 

leuq 5L laryya‘riorwfi oi? Frail is 13313 zfl.ile in.;nfi: cenri ;3
Vtitti the llill. Ilm‘;nararir ci‘itsiz,3 the ifinet alt? bill .for
killjxng cnnyfisi.vri~ urs"r lmjlln; Eoberlx3 ( 332:3“i0 31 fc1_
lows:

Of craw 13h t s especiallv fond. “ra“3ir' than

squiriin: and Pduollhu, fret under tie stones and
roots it ca; ies the m ashore "nd onto a conveni“nt huru
suriace, where they are pounded and mauled until the;
cease struogling. The no xt move is to onen a la“ e hole

a , z .A .4
‘

ir1 tflie lama-L jllst; btflcirmi tlie CUT’R'”lC€ , t‘lP(W1L: .uxicli {Jae
meat is extracted until nething hit ‘.3 eefity shell re-
mains. -ne dead crawfish vas held firmlv on the dround
with one foot while the white meat we: picked nut bit by
Leit a:.cl}siled in_a.}xnau near l3 LUltll there van; a 5000,
sizable hillfnl, which wcs Q"ather- up and conveyed to
the waitir ; nestling.

Cf

Wading. The writer has seen grackles wadin; in water
along the margin of a river in search of snails, crayfish,
and ins~cts. lhev did not hesitate to sutmnr'e their heads

-? 1 I‘ - ¢'\ - A x f“. ’N V \ . x a fi
iii (:1mieri 1A. rfzb ezie at, tile “IllJAIJJS.

“I .: . .. :7, - 3 " . , L ‘ . .
rl:inn LJilllulilae or food. oevcrcl aut.ors have seen

 

\ I -r . ., ‘v 1 ' I‘ ~ 1 f! In w . w: “r “\r {‘1 ‘
raokles £13 tux.Jc tie water +1m1.awoop down tc Muldi.43 lieat—

as L

' ‘ - O \. ‘3-" " __ 4"? 3' fl "I_O‘ . A L‘— ‘5 ‘
1143 b1_us 24. i kfli o1" ca tclzzi snuili 1.isll flchf Lif? sinciataa Ci

I 4.. ’ r71 w .1 '1 3 1 (‘3. ()(‘3 .4 4 '3 N. "‘ .._ ;_ . A 7" ’1 a“ _
the water keen rsenu, ixlézwof, 13in; bottau, lcioz Janalan ,
‘1 (‘ ~ *r : —, . . » ~ .- - . . : - " ,~.- " ‘

-cie). lno-1 acti T Were as sL_lliul as a bail.

Dunking food. Hot infreiuently : ronzed 'rackles, both

'0

 

een takinr

O

C')

in the wild state and in captivity, nave been

.‘ - arr "v‘- -. If 1‘ 3 . . 1
food to x.1ter MAC e it has ounheo and then

D)
('7
H

large piece.

(1

aaten. In a little park on the campu., where neatcwl were

fed stale lread, grackles were observed takins a larre piece

.LL.Q

 

‘. - \ 1‘ ‘. I y ‘ *1? l r‘ ,1 ‘ ,;_ ‘7 . «A . . ‘- ," I I r - . A v
Ff it to the river nee. by and uhngluo in. Iratlles in ca)-
. v . v r1 r a. ‘ o", ,- "v 'r‘. r v‘ . T " \ s I Q. ‘ . ‘ ‘
tiv1.t; xinrfl.ed.:aiwa'-. f, 3." LL. it,:1y-«Lereil tr\ -o idle :WJ—

A I . ‘ _~_ A \ u f} {‘11, ‘ ’_ . _1'_ a _ _ 1 _ ‘4
uttackiiu3atner lirls. lnrouuhout LAG li.eratxre taelc

 

 

are references to the “redation of 3rack15s on ‘tuer hirdn

m ,3 L‘.
es. iCO often tic au-

l—Jo

mostly on nest i1:s and smaller speé
thors of sons of those reports allowed etotion to hold sway,
thus rresenting a dark picture of the ravages of the grackle.
There are, however, enou;h authentic records to show that

there is a tendency for some individuals to attack and kill

)

other birds. Townsend (l\12:295) said ". . . I have seen

its foot while it deliberately peeked out its hrwins.
Eaton (19-4:250) renorted havir' seen grackles attack a

robin flcdblin' and kill it. He believed the nests of r31—
ins, least flycatchers, follow warbl rs, chip_in5 sparrows,

- ' I i V o A I
edai'xmumwian,

song Sparrows, purple finche

L)
w
0

mickoos, ;m;
other useful birds have been robbrd by QPRCKIGS. lice
(1937:14) inclrded the bronzed grackle flmon tze enemies of
the sonU Sp rrow. Foster (lOST), while coeratinr a “319
arm in Pennsylvania, observed purple grackles attackin
young nheasants and removing just the heads. se‘er (1912)
shot a male grackle that had just robbed a red—wing's nest
of a young-~the nestliné was still in the graokle's hill.
During the two years of field observation in this study,

the writer did not see a grackle attack and kill another

 

‘5'!”
rd. “ere were two instenees, however, V'hioh point/2:".
Lvsssd t.at trait. Once e robin scolded end chssed s Hale
:1Clrle Isira.its nosffirkJ tree, :nrggesti i; “‘st oer¢“its *he
ncflcle res fittJJfiLiLv ’\ r" t‘ rou‘, .ut it we“ not so—
:13L137 seer1~doirr, it“ hrs thor‘«exenrsle, illi}YT¢Jl;rW1 urxuitur—

~ ‘, 1 ‘. l . _ -v«"‘ ‘f1 ‘1'. r - ‘V
onsc, OCCurreo WHQD one of the fonaies c' tip hJIJ-PSBPCQ

.L J-.J
-rmls vxmszlttqcked srxllzilled in? the male. 73%: skull ri'ffi13
anufle had been opened 9nd the brains removed. (Tte Tale

d

t llnskcmi es thor j: ifaTisd Emeer

H

Mi an 'njured foot, and
fighting.)

Because of the resourcefulness find aggressiveness o
he grackle, it is conceivatle that it would tflhe e;"s or

ouna of other birds for food. It is preperly listed as an

nemy in this respect. However the extort of its destruc—

(D
U)
p.
C)

.iveness to other Speci not known, and it may have been

:verestimated due to the emotional element, which is likel"

,_ 1'

:c interfere with accuracy of observation.

 

 

\

iiC‘LS'i'lh) LI‘ILJ FLOCKIITC}

the Iresixino period, tut this trait becaae even gore apparent
‘Nheri itxs TCOStiMQ and flocking haoits w~re studiel Tum

rccmst, vkith its swirling mass cl

1‘ ~ n. I : r 1 ,~ ‘.. , .' 3 ,> ‘1‘ H I, . . _' - .\ ‘— . f: ..

ti\17 {flifi t sari scwrsti'.u, ot:; Iwztl 101‘.iaii g: ‘i_u¢, .ctrl1313d
'. I‘ V - ’ T ‘ I ‘0 Y ‘1‘ ’ ‘4 ‘1 V' ' x ‘ ~4‘

tkWasittention CL S’JCPni Juli] WCLuClD. Brewster (1830:5Cs)

studied.a robins' roost that was also used by stout 1,000
grackles and in his report included aany interesting facts
about the roosting habits of grackles. The most thorouuh
study of a Qrackles' roost which has been oublished to date
'(1953) is that of Dr. Lynds Jones (1397) made at Oberlin,

Ohio. This study covered the entire season from the arrival

of the grackles in the spring until they departed in the fall.

 

Snrirr :hn;stinfi
Early serin . At first, during the early part of the
ungration period, crackles were observed flying to roos‘
tdth flocks of starlings, red-wings, and cowbirds. no
choice of a location for roostin; varied from niyht to niyht.

F

hwwbridge Marsh, for example, was used by 500 to 1,00;
lflackbirds, including grackles, on four or five occasions
mudng the Spring of 1952. This marsh was used only when

an weather was good; during wet and windy weather the birds

 

 

 

 

 

140

number of migrants decreased, there was less shiftin
one roost locality to another.

By the end of Vareh resident chvhles, both "files and
females, of the Williams Dorm co :n7 reJularly rcosted stout

a mile and a hal, away in a thi:ket of sardtar willrw “"na—

resorted to more protected thieke s and swamps. As the

2 J.

l

‘ ted along tle mar
did not roost in tne trees near the nests 1s did those ob—
served by Jones (1397:45) at Oberlin. However, the writer

‘ la er observed that both male and female grackles nesting
at the.Bennett Farm colony, located in a windtreak of

snruees, did roost among the same trees.

Late sor.n:. After incubation was be un at the Wi‘liams

_—._u. U;

Dora and Trowbrid e Marsh colonies 'h: ‘; Li ~rag‘1r. p q;
x.) l C‘ K" T '
ed at the nest, while the males c:ntisu'd ff r‘ol f. L

same willow thicket that was used earlier. Hrles and fe-
males which were unsuccessful with nesting aétewnts contin—

ued to use t.at roost thr0u3hout the nestin season.

The roost. The willow thicket, Which was situated a—

long the eastern end of a small lake, was from one to two
acres in extent. It was a dense growth of sandhar will w

shrubs (Salix interior) standing from three to four meters

high and growing in water nearly a meter deep. Near the

thicket were a few aspen (Pogulus drandidentat and E. trem—

 

 

uloides) that were used as perches. Still more removed and

 

F4
n3
r

ll field were lar e trees

beyond the expanse of 8 sm v ,

“J

S’T'IMC

 

of which were oaks (Quercus alba and ;. rubra) that served

 

as gatherin; points for inc min; flocks at nivh .

Goins to the roost. lne close of thv day of activities

 

at the nestin, area (0:55 P.M. on March 25) was marked t" a
change in the behavior (f the grackles Just orior to their
departure for the roost. The Sound of the courtship song,
prevalent host of the time, was suddenly stooped, and in its
H : H

s were uttered by all. Small uroups of

x.)

stead loud chec}
three to five woved to the tons of the taller trees where
they remained F|r a few minutes, "checking" before denarting
in the direction of the roost. Those which left the Williams
Dorm colony (tusnethan a mile from the roost) flow along a
direct line at a height slightly above the level of the tree
tops. The flight speed of a pair of grackles was clocked by
an automobile snoedoneter as they were flying on their way

to the roost; it was fownd to be 23 wiles ner

Arrival a the roost. The roost was shared bv starlings,

 

red—winJS, cowbirdS, and 5racklcs. Starlings outnumbered the

' \-. '.
AOV-f (.C’ l“?.‘

4

other Species. Early in the spring t
half of the rocstin; “opulation. The grackles were in the
minority, forming from 5 to 10 per cent of the roosting
flock. The number or red—wings, which equaled that of the
cowbirds durin; migration, deer ased as spring advanced, and

at the same time the number of starlings increased, so that

 

 

 

,i

1“;
‘ ' . ’3 I. . .1 1' A -7 ‘ ' ‘ ‘ " ‘— r-« C. r‘ - ‘— . u 0 d ; ~
OJ'IHld-rniril_ uh.lN2'wetw: ".tal. .‘, frW” o-*t isorrljjhgs, .“, fir“

cent cowbirds, and about 3 oer cent Qrockles.

Bronzed grackles usually arrived at the roost in stall
groups of four or five, seldom more thin a dozen. Sone+imes
they arrived in nixed flocks. The time of arrival for all
Of the blRC birds began atout a half an hour before sunset,
at which time the light intensity was fluent lQO foot-candles
in general, the actions of all the blacktirds were sim-
ilar. The behavior fPCfl he time of arrival anti they were
settled for the ni;ht riyht be oonveniertly divided into
five activity nerieds as follows: (1) arrival at the large
trees, (2) flying down to the smaller trees and/or to the
thicket, (5) a noisy period of shifting about among the

bushes; (4) a quietind down period, (5) only voices of indi-

vidual birds, and finally (6) all Quiet.

.L

(l) bncn arrival small flocks of blackbirds gathered in

. .. \ 1 o .
t‘“,"_‘) ‘3‘ V‘ r‘ K .‘ “~ _', :1 Va - _ 'Yo “ "a ‘,. ,'; “'1" A (“.53 "I, .. * ../‘ ’-. 'fl} . ' 1 ‘7'
I-.. - L' .4 _ ‘V‘Agl ‘_ I‘ ~ - . v’ . " J: , \I L \4 , \A . - ' l

L! '
. _ I ‘ 1 I V. ‘ _ 1 _ 7‘ ‘ _ ‘u L _ ~ I ‘- {‘-
Il-‘-‘. < -~,. .’. .vw ~- -l-— ---3 - _\—~ vn- - ntfl‘. I) . .. .5 . n 1.11 ,
L44 L ' [J \.I'. o N) ' kt]- ' .1 I - . .; ~ .1 -.I . n '. LA -_ u) lg - A . --\ - -1 . - \ L' - I— ~. -L

pause, the entire flock wedld leave the tree with an ernlc—

_: w 0 v o ”i _ _o _ I' o _ o la 3 _ ' _- ‘.-
Slve Wnir of “anC. alter a brie; circlin, :ll,tt, uhiCu
‘ . -. - — : v , - T. . 1 - - \ .
seldom was beyond c_ew oi the roost, {‘0 ”cwld returr to

the large trees. The noriod of using the tall trees as a
perch usrally ended soon after sunset when the light inter—
Sity was about 10 foot-candles (Vic. 20).

(2) Some of the blackbirds (includin’ 5rack1es) beéan

U

1

flyinv down to the small trees near the willow thicket or

 

 

 

 

145

 

 

 

 

(5:30 7.00 7:30 8.00

00_ ' ‘ ' ' ' ‘ I '*r' ' ' I ‘ ' ' " I ' ' ‘-1oo
sop - 90
80— - so
70- . 70
60— - 60
50- - 50
4o- - 40
so- . so
20~ a so
)10- . 10
o- __ .s i_,—» o

r———— l'————1 I“ 3'1 r 5'1

IIIIIIIIIIIIfl!EEEEEIIIIIIIIIII!!!!!!!!!III[‘

l._.._. U |____...___ :l: '3

6:35 ' + ‘ Lviod ' ‘ ‘ ngso ' ' ' 'agoo ‘ L

 

Time of Day

Fig. 20. Correlation of activities of blackbirds
bar) going to roost with time of day and light inten-
:ity (curve),.harch, 1952. Numbers represent the fol-
.owing activities: (1) arriving at trees near roost
and circling flights back to trees, (2) flying down to
:mshes of roost and circling flights back to roost, (3)
sound in roost a babble, also some shifting about, (4)

noisy but quieting, (5) only individual voices of birds,
[6) all quiet.

tdv to the bushes before the first period of activity
ihey began entering the roost when the light inten—
innwed to about 30 foot-candles. for a period of about

mihour the blackbirds entered the thicket. Late arriv-

laudirectly to the bushes.

 

 

(3) The next period of activity began when all of the
roosting birds had left the trees and were shifting about
within the bushes. the sound of 3,000 to 5,000 birds gath-
ered in the relatively small area of the roost was a babble
of voices. There was a sudden cessation of this sound grior
to the taking off of the flock for a low circle flight. ouch
flights did not take Llace after the light intensity had fal-
len to 0.2 of a foot-candle.

(4) The babble gradually decreased as they settled into
their place: among the bushes. mt this time they were :itu-
ated at various levels from one to tho meters above the mater.
Grackles segregated themselves fron starlings. This period
of chatter :cntinued unti about 8:00 l.k.--cver an hour after
sunset.

(5) For another half an hour individual voices could be
heard. Finally only an occas13ral individual sterling or
red-wing was heard.

(6) Then all was quiet.

of the six evening observations made during this study
of spring roosting, three mere made when the sky vas clear,
and three when the sky was overcast. It was found that the
blackbirds began arriving at the roost about :0 minutes ear-
lier on cloudy evenings. in spite of an earlier arrival they
were not all quiet urtil about the some time as on clear

nights-~they merely required a longer geriod of settling dovL.

 

 

l 4 5

Departure from the roost. Four early Herring oleerva-
tions were here, two enen the weather was fair and two then
there has a light rain with an overcast sky. Uorrelaticn of
the morning activities at the roost with liglt irtensity and

w
I

tine of day is shown in fig. 9..

 

 

 

 

6 0
4O
o'q
I'J "
(H
aeo-
-.4
4—31
“(1.1.0-
E?
s: 0-
l 2 4
—
3 5
i 1 l L I I l 1 n L '44 L

 

l J J l l l;
5:30 6:00 6:50 7:00
Time of Day lutu

Fig. 21. Correlation of activities of
blackbirds leaving the roost (bar) with time of
day and light intensity (curve,, upri] 1952.
Numbers represent the following activities:

(1) first grackle sounds, (a) noisy to a babble,
(5) first blackbirds departed, (4) bulk ef flock
left, (5) stragglers left in small groups or in-

dividually.

-/

The first bird sounds in the morning were those of the
robin and the red—wing which began before 5:30 on a clear
morning and later on a cloudy morning. as the light of dawn
increased in intensity, the bird sounds increased also. by
the time the light intensity was 0.1 of a foot-candle the

sound had increased to a babble. The first few birds departe.

when the light reading was 0.5 of a foot-candle on a clear

 

14C

morning and 1.2 on a cloudy morning. Large flocks did not
leave until later when the light intensity was two to five
foot—candles. Following the several large flocks (200 or
more) were small groups of loss than a dozen, which departed
when the light intensity was much higher, from 10 to 50 foot-
candles. All of the roostinn birds had gone by 6:40 on a
clear morning and by 7:05 on a cloudy morning. By compar—
ison, Nice (1955) found at Columbus, Ohio, that the first
flights of gracklos left on a clear morning (mid-September
to October 17) when the light intensity was about 8.5 foot-
candles and on a cloudy morning when the light intensity was
15.5 foot—candles.

When a flock was about to leave the roost, the vocal
sounds were suddenly stilled. After a brief pause of quiet,
the bushes fairlv exploded as a black mass of birds swirled
upward and moved in a clockwise direction. As the great

~ - ...-: —..“‘.-.o"‘.‘rf‘
flOCk Of a thiusflhu 9P more hrrn:., omailtr .lcCKa .

,..1
D

it in nearly all directions of the compass.

Summer Boosting

Willow-thicket roost. The willow thicket near East

 

Lansing was checked twice during the summer and was found to
be used by starlings, grackles, and a few oowbirds. The
percentage of cowbirds using the roost was smaller than it
was in the spring. The total number of birds roostind there

was about 50 per cent smaller. The behavior upon entering

 

the roost was no different from that in the spring.

§_maple;§reg_ggost. A large roost of about 5,000 birds
(starlings, cowbirds, and ;rac:les) was observed on a few
evenings in la,e July of 1952. This roost was lecated in
shade trees, most of which were sugar maple \Acer saccharum)
in a residential district cf Alma, Michigan. The number
of each species was rou5h1y 35 per cent starlin s, 5 to 10
per cent cowbirds, and 2 to 5 per cent grackles. The num-
ber of grackles increased somewhat toward the end of July.
This roost had been used nearly every year for 15 years.
(It was used again during the summer months of 1955 also.)
In 1952 blackbirds began usilg it on June 25. Jones (1897:
45) reported that grackles began using the maple-tree roost

at Oberlin on May 16.
Flocking

During early summer grackles were observed going to the
maple-tree roost either as individuals or as small family
groups. On June 27 young grackles could be identified among
those in the roost not only by their duller plumage but also
by the double "check" note which they uttered. Throughout
the month of July there was an increase in the number of
grackles at this roost, as the young of the year and the fe-
males accompanying them began using the roost for the first

time.

 

143

Flocki 3, that is, the banding together of more than a
family group, did not occur during the melting season. The
grackles continued to go to the roost in small number or as
a disorganized flock of 8 to 10 individuals.

Flocking was first observed durind the last week of
August, when bands of 25 to 50 entered the roost at one
time. By mid—September the flocks had about doubled in size.
Compared to the size of the companies observed by Jones
(1897:49) at Oberlin (500 to 1,000) as early as July these
flocks were very small. Brewster (1990:568) also mentioned
large flocks entering the roost. The largest single group

observed in this study was composed of 500 to 700 grackles.

 

 

 

ESLJ;Ji£}xr{7{

During; 1951 and 19.32 the writer studied the life histo-

ry of the bronzed grackle, Quiscalus cuiscula versicolqr,

 

 

in southern Michigan. The primary objective cf the research
was to investigate the nesting cycle of marsh- and swamp-
breeding colonies. Other phases of the life history includ-
ed in this study were: (1) post—nesting activities, (2) the
growth and development of hand-reared young kept in captiv—
ity for a year, (5) the food and feeding habits of grackles
based on the analysis of 20 stomachs and supplemented by a
review of the literature, and (4) the roosting and flocking
habits of grackles associated with starlings, red-wings, and
cowbirds at willow—thicket and maple-tree roosts. A second
aim was to assemble and summarize from the literature per—
tinent data concerning: (1) the complex and confusing prob—

lems of the taxonomy and nomenclature of the genus Quiscalus,

 

and (2) the distribution of Quiscalus and the migration of

 

g, g. versicolor supplemented with unpublished return rec-

 

ords of 52 bronzed grackles handed in the East Lansing vicin-
ity.

Investigation of the nesting cycle was centered prima-
rily on a breeding colony of bronzed grackles located in a

small marsh near East Lansing. The predominant vegetation

of that marsh was meadowsweet (Spiraea alba) and reed—canary

 

 

 

 

 

150

grass (Phalaris arundinacea). Other important habitat cem~

 

penents were dead tree stubs, water where the bushes grew,
organic mud, and a zone of plants bordering the marsh. A

small beg rush (Juncus tenuis) and swamp milkweed (Asclegigs

 

incarnate) included in this zone were important constituents

 

of nest structures.
During the second year additional information about the
growth of the young was obtained from a second marsh of the

same type and from a willow swamp.

Taxonomy and nomenclature. The nomenclatural history

 

of Quiscalus gpiscula is long and complicated. The bronzed

 

grackle was first recognized as a separate species by Ridg-
way in 1869. Steineger later (lu85) referred to it as a sub-

Species of Quiscalus guiscula and shortly thereafter (1886)

 

it appeared in the first A.O.U. Check—list as Quiscalus guis-

 

Eula aeneu§_Rid5way. After further study of the relationships
of the three forms of this species it was again listed as a
separate species in the Nineteenth Supplement of the A.O.V.
Check-list in 1944. However, four years later the A.O.F.
Check-list Committee reversed its decision and once more
reduced the bronzed grackle to subseecific status. Current—

ly (1955) three subspecies of Quiscalus guiscula are recog-

 

nized as follows:

Florida grackle, Quiscalus quiscula qpiscula (Linnaeus)
Purple grackle, Quiscalus gpiscula stonei Chapman
Bronzed grackle, Quiscalus quiscula versicolor Vieillot

 

 

 

 

 

Distribution and migration, Versicqlgr_is the most

 

widely distributed of the three subs ecies. Its breeding

$—

range extends from the Rio Grande valley in northern Mexico
north along the eastern slopes of the Rocky Mountains to
Great Slave Lake in Canada, east to southern Hudson Bay and
southern Labrador, south through New England, southwest a-
long the western slopes of the Appalachians to Louisiana,
west to northern Mexico. It is more abundant in the forest
biomes of its range than in the grasslands. The bronzed
grackle is common in both the Lower and Upper Peninsulas of
Michigan and is found on several islands in the Great Lakes.
The winter range of this form includes the Rio Grande
valley, the lower Mississippi valley west of the Appalachians,
and Georgia and the Carolinas east of the Appalachian range.
Small numbers winter over as far north as the lower parts of
both Wisconsin and Michigan and the State of New York.
Spring migration of bronzed grackles begins in early
February in the Rio Grande valley and in mid-February in the
lower Mississippi valley and the southeastern states. North-
ward progress of spring migrants is more rapid along the
Mississippi valley and slowest over the Great Plains region.
The first migrants to reach Michigan arrive by early March.
Those of the northernmost part of the breeding range reach
the nesting grounds in May. Male grackles arrive at the
breeding grounds in Michigan from one week to 10 days in ad-

vance of the females.

 

 

 

152
Fall migration begins in the northern part of the
tnfieeding range in August. The last migrants leave Michigan
111 late October or early Novemb r. On the basis of banding
:recoveries grackles from East Lansing and vicinity were
fourui to go as far south as Alabama, Louisiana and Texas.

IWost of them go to Tennessee and Mississippi.

I
.

The nesting cycle. At East Lansing courtship begins
as soon as the first females arrive in the latter half of
Marwfli. In selecting a mate usually two to four males com—
‘pete fbr a single female, until, finally, one dominates.

The courting males follow the female on short flights from
the nesting area. For the purpose of intimidation they dis-
play and sing, as well as "bill-point" before each other.
The period of selecting a mate lasts from one to two weeks.
‘Unpaired males occasionally continue competing for a mated
female for as long as five weeks after the first females
arrive. Monogamy was the most common kind of mating rela-
tionship observed.

The bronzed grackle does not show definite territorial-
ism, or, if any, it may be a kind which Nice (1941) called
"Type D," that is, one which is restricted to a small area
around the nest.

The grackle's song is given by both sexes and is accom-

panied by plumage display. The male, in addition to utiliz—

ing it for courtship and intimidation, also uses it for

 

 

155

 

caJLLing his mate. The female sometimes uses it in response
to :1 male's courtship display, but more often, for calling
her'znate or replying to a call from him.

Courting males also have a flight display. This kind
of flight is a slow even glide, effected by (1) depressing
the central tail feathers, and (2) using a fluttering wing
beat.

The female begins to hunt for a nesting site during the
first two weeks of April. Her mate or two or more courting
Inales follow her as she searches.

In I952 a survey of nesting sites in a l2-square-mile
area revealed that 56 pairs had located their nests in small
marshes or swamps and 58 pairs in coniferous trees. On the
average, the distance between a colony and the one nearest
to it was 0.6 of a mile, and the greatest was one mile. The
heights of the nests varied from 25 to 90 centimeters in the
znarshes and swamps, and from 7 to 25 meters in coniferous
trees.

This survey also revealed some facts about the density
of the nesting population: (1) the average number of pairs
per colony was 7.4, the marsh and swamp colonies averaging
6 gsirb, anf :12 penifcruus free TLLSHLES ;Y~“l"'9 ‘ l ..
and (2‘ i.e ,Lr-uls ic1.~.ensi Ev "' “ J
mile (r approximately 02

Nest construction besun fluring the first or second neek

of April. The time of the beginning and the duration 0‘ the

 

 

F.)
U1
LP

.pericm of nest building was correloted vith the 4V9T3;5

The nest is constructed entirely by the female. The
znale sometimes symbolically displays nest building, but his
:najor role is one of guarding the female. Normally there
are four stages in the construction of a nest: (1) platform
01* suspension pocket, (2) outside structure, (5) plaster cup,
(4) lining.

Nest building begins with the fastening of a few strands
of milkweed fibers among several upright branches of the
bush_and grass to form either a platform or a loosely sus—
pended pocket. To this support are added coarse stems and
leaves of weeds and grass, string, paper, and other materials.
Next, the inside of this bulky mass is plastered with wet
organic mud, beginning at the bottom apd working up to the

‘ rim. A lining of fine plant stems, mostly Juncus tenuis,

\ covers the plaster cup. A few strands of the lining are
anchored in the rim of the plaster cup while it is still wet,
and more is added downward so that the bottom of the nest
is the last to be covered.

On the average, the first egg is laid 2.3 days after
the lining is complete. Usually one egg is laid oer day--
in the morning between 5:00 and 8:00. The clutch size ranges
from three to six, the average being 4.5.

In most cases incubation begins on the afternoon before
the last egg is laid. The female alone does the incubating,

being more attentive during the cooler parts of the day (20

 

 

 

 

 

155
to 50 minutes on the nest at a time) and less attentive dur—
ing the afternoon (5 to 10 minutes). The periods of inat-
tentiveness vary from 15 to 50 minutes, depending upon the
time of day and the weather conditions. The average length
of the incubation period is 12.7 days.

During incubation the male Spends 25 to 50 per cent of
his time guarding, while perched 20 to 40 feet from the nest.
He often continues guarding when the female is away from the
nest. The male also visits the nest, and sometimes feeds
the incubating female. Newly hatched young weigh 5.5 grams;
the wing lethh is 9.1 millimeters; the eyes are closed, and
natal dOWn 10 to 20 millimeters long is present on the cap—
ital, spinal, humeral, femoral, and alar tracts. TWO days
after hatching, pin feathers of the primaries project one
millimeter through the skin, and by seven days they begin
to break out of their sheaths. The eyes can be seen throuqh
Small slits on the fourth day and are nearly wide open on
the seventh day, at which time the nestling shows the first
siqns of fear. When the young are ready to fledce, they are
covered with feathers except for an area around the eyes;
the tail is from 15 to 50 millimeters long; the weight is
79 grams; and the wins length is 75 millimeters. They
fledge at the age of 12 to 14 days.

Of the 55 nests with eggs, only 1.2 young fledged per
nest. TWenty—three per cent of the eggs were deserted dur-

ing incubation because of weather; 26 per cent (as nestlings)

 

 

156
were destroyed by predators. A Cooper’s hawk was believed
to be one of the predators. Six per cent were taken by the
investigator. Out of the 45 young that were handed, nine
were probably removed from the nest by the parent bird in an
attempt to dispose of the band.

The female does all of the brooding. At first she fol—
lows a rhythm similar to that established during incubation.
After that she broods less each day, but continues it at
night until the young have left the nest.

Both parents feed the young. During the first five
days the male makes about 5.5 feeding visits to the nest
per hour, as compared with 1.1 trips of the female. When
the nestlings demand more food and require less brooding,
the female increases the number of trips to four per hour,
while the male decreases his number to 2.5 trips per hour.
The male makes the first and last feeding trip each day,
while the female broods.

Nest sanitatiOn consists of the removal of fecal sacs
by both parents, and the cleaning of the nest beneath the

young by the female.

Postfnesting activities. During a three— to four-week
period following nest leaving, young grackles are dependent
upon their parents for food and are semidependent for another

week or longer. Family groups remain together during this

period of dependency.

 

 

157

Hand-reared birds. Three nestling grarkles, a male 3

 

dayws old and two females 11 days old, were kept in captivity
for* 15 months. They attained full size at the age of about
55 (days. The larger features of the male became evident
beihore its juvenal plumage was completely developed. In all
trucee young the breast feathers of this plumage were indis—
tixictly streaked. The postjuvenal molt lasted through the
first three weeks of July. The male attempted to "sing"
soon after acquiring the winter plumage in late July. The
females did not sing until late December. At that time the
Inale's song was about the same as that of the females. The
latter postured and begged before the male, but copulation
was never observed. One of the females showed signs of nest

building during late Kay.

399g. An analysis of the stomach contents of seven
nestling grackles revealed that they had received nearly
all animal material, which included spiders, small crustacea,
and insects. The food of adults collected at a blueberry
swamp included about 40 per cent animal material and 53 per
cent vegetable material. From the literature the stomach
analyses of nestling grackles conducted by Real (1900) and
Hamilton (1951) were compared. These studies revealed a
higher per cent of animal than plant food:~ 74 per cent

animal and 26 per cent plant food (Beal); 39.1 per cent an-

hnal and 6.4 per cent plant (Hamilton).

 

 

 

153

Boosting and flocking, As soon as grackles arrive in

 

the Spring, they roost in flocks mixed with starlings, red-
wings, and cowbirds. At that time they use marshes and
thickets for roosts. The females roost on the nest from the
beginning of incubation until the young leave the nest. Dur-
irm; that time males 0 LZTLUV to rcost in the marsh or thicket
which they used in early spring.

A willow-thicket roost was used by 5,000 to 5,000 black—
birds, mostly starlings with fewer ccwbirds, red—wings and
only 5 to 10 per cent grackles. A maple—tree roost was ob—
served in central Hichigan where about 5,030 starlings, cow—
birds and grackles began roosting on June 26; only two to
five per cent of these were grackles.

_Late in August grackles begi to gather in flocks which
increase in numbers as fall approaches. The largest flock
of this species observed at one time (October 2, 1952) num—

bered 500 to 700.

 

 

LIST I

PL\NTS COMMONLY FOUND IN THE
VEG STATION ZONES AT T?O.ur 1E MARSH

The Jungug tennis Zone

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

lece ria striata Juncus effusus

Poa pratensis Rumex verti_cillatus
Scirgug atrovirens Ranunczlus parviflorus
Scirpus lineatus Penthorum sedoides
Scirous cyperinus Asclepias inoarnata
Scirous atrooinctus Varbena hastata

Carex vuloinoidea Scute llanig eEi lgoiigolia
Oarex scoparia gycopus rube llus

Carex luoulina Eupatorium perfoliatum
Junou§_tenuis Solidago sp.

The Phalqgis Zone

Phalaris arundinacea

 

The Sgigaea Zone

Sniraea alba Salix gracilis
Phalaris arundinaoea

 

 

 

@Yoha Zone
Typha latifolia

 

The Calamaarostis Zone

Calama&rostis neglecta Carex aguatilis

.. _.'___ .—

Carex scoparia Scirpus atrocinctus

 

 

 

Spirous cyperinus

 

 

 

 

LIST II

VERTEPRATES OTHER THAN BIRDS OBSERVED AT
TROWRRIDSE JARSN BY THE AUTHOR AND BY CORNELL% (1950)

Mammals

Masked shrew, Sorex cinereus%

Raccoon, Procyon lotors

Thirteen—striped ground squirrel,
Citellus tridecemlineatus

Meadow vole, Microtus gennsxllanigug

Muskrat, 0ndatra zibethica

Meadow jumping mouse, Zapus hudsoniusa

Cottontail, §1lvilagus floridanus

 

 

 

 

 

 

 

Reptiles

Garter snake, Thaanphis sirtalis
Snapping turtle, Chelydra serpentine
Painted turtle, Chrysemys Riots marginata
Blanding's turtle, Egys blandingii

 

 

 

 

Fish

Western mudminnow, Umbra_limi
Brook stickleback, Eucalia inconstans

 

 

 

LIST III

STOMACH CONTENTS OF 2,546 ADULT GRACKLES
(Beal, 1900)

Per cent of
Total Diet
Animal Food

 

Insects . . . . . . . . . . 25.4
Predaceous beetles . . . 5.6
May beetles . . . . . . . 4.9
Snout beetles . . . . . . 2.0
Other beetles . . . . . .l 1.0
Caterpillars . . . . . . 2.5
Grasshoppers . . . . . 3 7.5
Other insects . . . . . . 2.5

Spiders and "Myriapod " . . 1.5

Crustaceans and Molluscs . 5.1

Vertebrates . . . . . . . . 0.5

Total . . . . . . . . . . . . 50.3
Vegetable Food

Grain . . . . . . . . . . . 46.5
Corn . . . . . . . . . . 57.2
Oats . . . . . . . . . . 2.9
Wheat . . . . . . . . . . 4.8
Others . . . . . . . . . 1.6

Fruit
Domes tic o o o o o o o o 2.9
Wild 0 O O O O O O O O O 2.1

Weed seeds . . . . . . . . 4.2

Mast, etc. . . . . . . . . 14.0

Total . . . . . . . . . . . . 69.7

 

l

 

 

 

 

 

LIST IV

STOMAOM CONTENTS OF NESTLING GRACKLES
(Real, 1900; Hamilton, 1951)

Beal Hamilton
Pharmal . . . . . . . . . . . . 74.4 per cent 39.1 per cent
Insects . . . . . . . . . . 60.0 " " 48.2 " ”
Scarabaeid beetl grubs . 19.0 " " X
Carabid beetles . . . . . 10.0 " ” x
Elaterid beetles . . . . . -—-— x 20.8
Weevils . . . . . . . . . 5.0 " " -- -
Other families of beetle 1.0 " " x
Grasshoppers and crickets 21.0 " ” [8.d " "
Hemiptera . . . . . . . . ——-* D9.Ql " "
Caterpillars . . . . . . . 6.0 " " ---~
Ants . . . . . . . . . . . ---- " " x
iEarthworms . . . . . . . . . ---- 10.9 " "
Mollusks . . . . . . . . . . ---- 5.2 " "
Millipedes . . . . . . . . . x 0.8 " "
Sowbugs . . . . . . . . . . . -~-— 3.4 " "
Spiders . . . . . . . . . . . x 5.4 ” "
FiSh o o o o o o o o o o o o "’"-'" 6.5 H H
Ihnphibians . . . . . . . . . —-—- 8.5 " "
Mammals o o o o o o o o o o o ""'""' 005 H "
Vegetable . . . . . . . . . . . 25.6 " " 6.4 " "
Grain . . . . . . . . . . . . 15.0 " " IT. " "
Fruit . . . . . . . . . . . . 7.0 n n 1.8 H H
Green grass . . . . . . . . . ---~ 5.2 " ”
Grit o o o o o o o o o o o o o """ 4.5 II N

 

LIST V

STOMACH CONTENTS OF 14 JUVENAL AND ADULT
GRACKLES FROM EAST LANSING VICINITY

Animal
Insects
Beetles: thisoids, HydrOphilids, and Platystomids
Hemiptera: Pentatomids

Homoptera: Cicadellids and Cercopids
Lepidoptera larvae
Spiders

Vertebrates: Small vertebrae, possibly V? immature toad;
down feathers.

Vegetable
Seeds: Blueberries (Vaccinium sp.)
Fruit pulp: Blueberries
Moss

Grit

Quartz, feldspar, and cinder

 

 

TABLE I

RECOVERIES OF THONZLD GHACKLES FANDED AT
EAST LANSING, LANSING, AND LAKE ODESSA, MICHIGAN

 

r Summer Fall Win r Total

     

 

Data from banding files of Michigan State
College and of C.C.Ludwig.

TABLE II

AVERAGE WEATHER CONDITIONS AT EAST LANSING, MICHIGAN
FOR THE MONTHS OF MARCH THROUGH JUNE, 1951 AND 1952*

 

     
 
 

 
 
   
    
 
  

 
 
   
  

 
  
   
   

Temperature
3 F.

Sunshine
< 1‘78}: semi

Wind
(M.P.H.
v. Max.

Precipitation
Inches

   
   
  

 

 
  

    

V.

 
    

water

   

 
  
      

      

O O O O

   

  

*Data from U.S.Department of Commerce, Weather
Bureau Station Meteorological Summary.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N . . . . . . . . . qumwtm Wipmnao oo HoxOHHm
N . . . . . . . . . 20MOHH e Hmommo ma HoerHmcHx ompHmm
N . . . . . . . . . moHsm Hog mH HHpe on Ho HHHsm mmHeHno
a . . . . . . . . . mocH a ww#-v© GMOHU MSmnpanz
a a a x . . . . . . . . nH20Ho ma mHs HeHscmL m>oe wcHanoz
x O O O O O O O 0 O 0 O MHNVHH .m'QFddrHOO m>OU Moom
x x . . . . . . . . . owes HHHnm «HHmmmo mrHCm m .HomHHh
a . . . . . . . HmHHmo> meHH e Home HomoHHHM
x a a a . . . . . . . . . mmeHHmec «OHasm pooo cmOHHme<
a x a a . . . . . . . . . mcHHOHHo ssnuHOH mHom
x x xx . . . . . . . . . . mHOOHsHH wSHHmm HHUH chHmHH>
A . . . . . . . . msoHddHoo wdmmeenH Hamwm mHH omxomn mch
N . . . . . . . . . mnemxHH : HOHUHmM mohmwo
a . . . . . . . . . . meanecHH oopsm Mae: ceHmcHsonmncmm
_ N . . . . . . . . HHHmmooo HopHmfloo: Mess m.Homooo
x _ N . . . . . . . . . . . wHoo He was: Hmmp emmHHsnmsHm
- - «a . . . . . . . . .-M-M-Mm:HH95H mmn< Mose Mosam
a x . . . . . . . . moHoqmmHNusHm west deHHms
a x x xx . . . . . . . . . mHHme MwsoNHnoxH :Hmuqu awe mH
i:: xl,m. a . . . . . . . meadH HHm.HucoH mSHSmpom :HmupHp onOHHms:
::s%.aH a M . . . . . . . . mcmé we H> wecHHOHsm cOHem zoon
a . . . . . . . . . . m..Hm0HmH coon QOHeg oan ummHo
x M x . . . . . . . . mimOHUo; mm:emJH©o. oneHm mmHHHanmHs
.n H H1 .a 8 as .a “u a
T O .8 a J J. TL 8 8
me O 8 as e 8 He _S e
M 3 3 P a e M _ 1 D.
o H+ w! n. Hr P 3 T} I
A m. cm cm“ c c N. QUG cw mwflnvnwmm. WDCQU WEHZ COSEOO
8 on. 9
1 w. .a J
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pqmcmem pceHwawHe

 

 

 

 

 

AHmuHHs exp up poo one HommHu HHmHHoo up some mmonu MHms mMmHHmpmtv
mm. :4: an. .ommH .szm 3H5 DB momcaumHH Eomh mmmsa WUfiHmmzomB P: Zmflm QOHm

LL

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H- N N . . . . . . . . . 5H0040 flwH5m0H0H 30HH0mm wHom
N N . . . . . . . . MfldeHamm WNHMM0H02 30HHmmm Hamam
N N . . . . . mHmwwonwamm WwH50HmmmxH 30HHaHm Hmcqm>wm
N N . . . . . . . . . . mewHHp m5admw HquHcHom
N . . . . . . mHH5CHvH00 ;:mo 0EHOHm HmHHono
N N x N O O O O O O O O O I “mpm \nw flpflpOHOM-M UHHDgoo
N N N N . . . H0H00HmH0> «H500H5d wanowH5m 0HN0er cmNHOHm
N N N N . . . . . . . . Mflmecmone lwdmemwm mHHaacmm
N N . . . . . . . . . . mqwnw HHHm :H5pm MHaHzowmme HHmpmwm
N . . . . . . . m5H 0:HwNH N55020HH0n NcHHonom
N N N . . . . . . . . . m50Hpm 0805 How am 30HHmHm HmHHmcm
N N . . . . . . . . 5: HH:. H:.Anpomo umoHHHISOHHmw
N N N . . . . . . . . mHsovumH :0 oHchn HmHnH53 30HH0»
N . . . . . . . . . MMHmmH5> w5HH5pn mcHHHmpm
o o o o o o o o o o o Mnflwflm mHHmem Chflpmjnfim
N . . . . . . . . m5HH05N HaH HE mH,5H5B chom
N N . . . . . . . mecmpmAfl‘ m5H0Hm0pm 0H0 50H; gme: meHHnapHoam
*N . . . . . . m5Hpa5H04 mm :50 fiuEHme HmHa HmHsE UmHHHHanOH
. . . . . . . wozqu;H HMome m5>H05 30H0 HHmpmmfl
N . . . . . . . . . . . mHH5; 0Hw0HH chHme 0HHH5H
N - . . . . . . . . . . 0pr5H 0555HHm 30HH53m HHmm
.N N *N . . . . . . . . MOHdoHp owooHHdeHH SOHHnEw mmHB
M :i N . . . . . . . mHproHHm wHHnmoemHm NHwH omuHom
_ N-xN . . . . . . . . . HHHHoHp Nmmoc {Hag HmnopmomHH HmcH<
WH N N . . . . . . . . H w5c: HNH 05H50HNL wHHQmuHN .m
M N . . . . . . . wqwowmp5m m5H000H5H0Q H0N00m©003 H5309
J N” no 5d 3 cu Ta 8 an
TL 0 .8 8 J J TL 9 8
8 O S 9 8 8 8 S 8
M 3 3 P e 8 M 3 0.
Q T: T: p p T. T:
O T: U U. . . O .U U
A u 95 H5 ‘ ¢ A 95 H5
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J . n. J J H . .
. _p Hy mmHomgm m5Hm© 0802 508800
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pcmmHmmm pcmHmHmHB

 

 

 

 

:co5chzoo: HHH MHmZB

 

 

TABLE IV

NEST SIZE BASED ON
BRODZED GRACKLES

SIX NESTS OF
FROM TROWRRIDGE MARSH

 

 

 

 

 

 

 

 

 

 

 

 

 

Average Maximum Minimum
Dimensions of whole nest
Outside diameter 16.48 cm. 18.0 cm. 15.0 cm.
6 1/2 in. _ _#“__#_
Outside depth 15.45 cm. 16.7 cm. 10.0 cm.
5 5/8 in.
Inside diameter 9.98 cm. 11.2 cm. 9.4 cm.
_, 3 7/8 in.
Inside depth 7.60 cm. 8.5 cm. 6.0 cm.
5 in.
Plaster cup
Inside diameter 11.40 cm. 12.2 Cm. 10.5 cm.
4 1/2 in.
Inside depth 7.08 cm. 8.7 cm. 5.5 cm.
2 7/8 in.
Thickness of bottom 1.71 cm. 2.5 cm. 1.1 cm.
1/4 in. “_
Thickness of side 0.84 cm. 0.9 cm. 0.7 cm.
“mm___ ____ 5/8 in.
Thickness of rim —~—0{6O cm. 0.8 cm.““ot4”“em.‘
1/4 in.
Per cent of nest weight
Outer coarse material 24.6 55.0 18.0
Plaster cup 69.5 74.0 61.0
Lining 5.9 7.0 4.0

 

 

 

 

 

 

TABLE V

NEST COMPOSITION PASED ON SIX TESTS OF
BHONZfiD GRACKLES FROM IROWBMIDQE MARSH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Average weight Per cent of
in grams nest weight
Outside
Milkweed 1192;-.- Mb” ____ _H_~1_i.12,__1__________6._2 _
Grass stems and leaves 14.28 7.9
‘Weed stems and leaves 8.58 4.6
Leaves of trees trace trace
Roots of grass and weeds trace H bv__trage___
Sedge 0.55 0.1 I_
Juncus ' 0.16 trace
String and rag 0.51 0.2 ‘_
Paper 0.58 0.2
Debris. crumbled bits of
leaves, etc. 8.76 4.9
Total 44.05 24.6
Cup 124.04‘ 69.5
Lining
Juncus tenuis . 4.59 2.5
Milkweed fiber 0.05 trace
Fine grass stems and leaves 1.55 0.8
Fine grass roots 0.28 0.1
Sedge 4.25 2.5
Total 10.7 5.9
Total average dry weight 178.77 99.8

 

 

 

 

TABLE VI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ixMJJTIUN 0F‘IM3 P.3 (F EHOEfinmlalRAOKLES
‘ AT THO {ISRIDG UL 16.51514. , 195]. I‘LND .19 53
1 | 1951 1952
1 Height above water (Meters)
i Average . . . . . 0.60 0.45
7 Maximum . . . . . . . . . . . . . 0.69 0.66
1 Minimum . . . . . . . . . 0.25 0.55
‘ Distance from nezirest grackle's nest
Average . . . . . . . . 15.10 26.50
maximum . . . . . . . 27.40 50.40
Minimum . . . . . . . . . . 9.10 18.20
Distance from op en water
Average . . . . . . . . 5.18 5.58
Maximum . . . . . . . . . . . . 55.50 10.00
minimum . . . . . . . . . . . . 0.61 0.61
TABLE VII
LOCATION OF 1\‘_EST8 0? 82011511213 OR .QKLES 1N
r.12— “HUKHJJ EAREA 5T.&KIPI,rESING, 1952
habitat Situation
._. I 1;: .
(:4 U)
3 a A a 2 a . m3 532 2
.O O :3 3 U) ID 03 H 0H .0 :5 r-{ U) (D "-4
8 r4 m m 0 F4 £4 0 0 #1 53m le01m 0cm
3 O -H 81 an 42 m m +20 r1w~ L. ;:h
C2 0 H [-4 .0 'r‘1 «H C, S—I 3:3 {:1 (D (D (D 0)
O D. O "3 C s: 0H an 03 <1) '1) <1) :1 "j 43 <1) 4.)
m Q G H x w 3 33 $553 2%:
3' "4 :32 E3 '3 ES ‘3 .fi "-4 "—4 :4 .c; o H O :0 ‘ $4 I
H‘Maaaaeee‘aesass 3.5
{3 :3 éfg 18 f; g: m U) co m 7) <3 2 m
1. 6 x x _ 1 5 24.12 0.45
2 12 x 9 5 10.18 9.09
5 7 x '7 5.51 9.00
4 15 x 15 5.65 15.84
5 8 x X 8 7.69 0.68”
5a 1 x X 1 596.24 0.60
6 l x x 618.82
7 4 x x 4 12.19“ 0. _69_
15 x x 10 1 2 12.40 1. 52
8a 1 x x 1 160.95 1.01
9 2 ' x x 2 18.28 1.52
10 6 x 4 2 10.50 9.58

 

 

 

 

 

 

 

 

 

 

 

 

 

 

T

 

TABLE VIII

RROLZED GRACKLES FHHOUiHOUT THE :PEEDING RANGE
(Figure is number of times noted by 50 authors)

 

 

 

 

 

 

 

 

 

 

 

 

 

!
1
LOCATION OF NESTING SITES 0F
Habitat Sunoort
Shade trees in city 8 Coniferous trees 20
Cemeteries and parks 4 Deciduous trees 22
Farm and estate dwellings 6 Bushes 9
01d apple orchards 2 Vines 5
Cut-over land 1 Cattails 2
Lake margin 4 Bulrush 2
Pond 2 Grass 1
Marsh and slough 7 01d woodpecker holes 7
Swamp 4 Hollows in dead tree stubs 8
Stream borders 8 Knotholes in trees 7
Bottomland woods 1 Man-made structures 7
Island 2 Osprey’s nest 7
TABLE IX
TYPES OF SUPPORT FOR NESTS 0F
BROFZED GRACKLES FROM REPORTS BY 50 AUTHORS
Trees Bushes Vines Herbs Others

White pine Willow Grape Cattail Osprey nest
Korway pine Alder Grass Bridge

Norway spruce Chokecherry Bulrush R.R.bridge
Hemlock Nuisache Cornice

Cedar Eaves trough
Willow Beams of hay barn
Cottonwood Hollow dead trees
Lcmhardy poplar Woodpecker holes
Paper birch Dead tree stub
Oak Knothole in trees
Elm

Sycamore

Plum

on elder

Maple

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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TUELE

X1

.1. SULLARY OI“ LEG-LAYING AND INCUBATION
AT EAST LANSING ,IxfI CHIGJQG ,

DURING 1951 AND 1952

 

 

 

 

 

 

 

 

 

active Number Clutch No. Days of
Nests Bees Size lilagghatiani_
Trowbridge |
Marsh 1951 l5._”m_wu66 4.5* h__12.75w-__
Trowbridge ‘
Marsh 1952 6 25 4.4* 12.66
Forest Rd.
1952 8 56 4.5 -----
Collins Rd.
1952 4 18 4.5 —————
Total 55 145 --- -----
Average -— --~ 4.5 12.70

 

 

 

 

 

‘ *Two nests in which U18 eggs were destroyed
before the clutch was laid were not included in
the computation of clutch size.

TABLE XII

NEsTING SUCCESS or THE BROTZED GRACKLa
AT ERST LANSING, NICHIGAN, AND knDISCN, WISCONSIN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

E. Lansing Madison
Active nests 55 62 __
Per cent successful 55 _ 55
Number of eggs _W_fl-_w-14§_u_w_w_m288__ _.
Number hatching 91 209
Per cent hatchinz 65 75
Number of fledglings 56 155“ _m__
Per cent of eggs 25 47
Per cent of young 40 65
No. Ler successful nest 5.1 4.5
No. per active nest 1.1 2.2

 

 

 

 

TABLE XIII
NESTING SUCCESS OF THE BRONZED GRACKLE

. M. T. M. F. Rd. C. Rd. Totals

ve n t 2 .
*T. M. is Trowbridge harsh colony; F. Rd. is Forest
Road colony; C. Rd. is Collins Road colony.
TABLE XIV
CnUSfB 0F FAILURES IN NESTS 0F BRONZED GRACKLES

Trowbri Trowbridge Forest Collins Totals
‘ 0 ‘ 0 v Y

*Per cents in parentheses are based on total eggs laid.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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TLATE l

Fig. A. Trowbridge harsh. View from marsh toward
observation tower. Field in background. April 28,
1951.

Fig. B. Trowbridge Marsh. View from observation
tower along south margin toward northeast showing: (1)
Phaleris zone; (2) Juncus tengig zone; (5) Old field
zone.

 

 

PLATE 1

.. w,

»......-.v

 

 

 

 

 

Big.
tc.er toward r

.11.

eyon., GL1 Trxw ri
Zr 195l.
‘0‘ ' i-l "
L .L J. v
I 1 1.‘ ,.‘ ‘\, A
I. ,1. K J \. JL'

TLATE s

I‘Sh o
iraee elbu

Bu .
mg ‘5
.R. 1 “def

L'L‘H'CG:

. ‘ _ ~ 1 H '
h‘ . u ."‘_I I‘- "V \
10‘- -.-s . u .1. 11
._ (‘I '1
q ‘ . ‘4 Y“- “‘ ‘1 (I
)?L U .. S. J. L‘ ”l ‘41‘. -9

View from observation
zone,
at ugper right.

open water
Alril

 

 

PLATE 2

1.9

In
I

\ : I ‘
figuf‘fi.’
.- ’ v.9 3

fl“!

 

 

PLATE 3

Fig. A. Trowbridge harsh. View from southwest part
of marsh. nrrow shows lOCation of Nest 1. Observation
tower appears beyond black willow tree. April 28, 1951.

Fig. B. Cross—sectional View of Nest 17 from Trow-
bridge Marsh. lnk lines outline plaster cup, (1) outside,
(a) Llester cup, (5) lining.

 

 

PLATE 5

r

€34li ‘11

 

I’ll-UTE 4

Fig. A. kichigan nvenue, East Lansirg. Austria
fine the location of nestin Area 3 where seven nes
- 3 )

5
were Situate‘jo llbril 1.5, 195;.

F's. B. Bennett Fern near East lensing. Norway
sgruce windbreak in :hich 15 pairs nested. Farmhouse
beyond trees. upril 30, 195;.

c+IJ

U)

H.

m

 

 

PLATE 4

 

 

FLT-1TH: 5

Fig. A. Forest Road colony. View from south toward
ogen water with fipiraea alba bushes in bac‘gromnd. Note
truck on Forest Road, which divi es this bush marsh. Nay
28, 1953.

Fig. B. Bronzed grackle's nest with four eggs. Nest
mas located at area 5a in a black MillOW with a tangle of

grapevine. Nay 7, 1952.

 

 

 

 

b‘in. u.
Lillow SWsr¢
willow trees,
b?, 1954.

Fig. B.
bar willow at
1952.

[LATE 6

Collins Road colony, nesting area 7. A

xith a thicket cf sandbar nillo: and black

where four pairs of gracklcs nested. key

Bronzed grackle's nest among stems of sand-
Uavaneugh colony, nesting Area 8. Nay 2,

Fig. B

PLATE 6
Fig.

 

 

 

Fig. A. Young bronzed'gracklc.

TW'rr C‘Z
waj 6, lgua.

Fig. B. Young bronzed grnckle.

May 15, 1952.

Pl.£PE 7

z) ‘ $- A,
lhe first coy.

The fourth day.

 

 

PLATE ”7

 

Fig. A

 

IWWW1«:MEE§”"U¥WWW; mm
“W

mg. B

IV. a y

bfligo 7*.

15, igsz.

Fii‘ZO B0
15, 1952.

Fig. 0.
25, 195s.

Young

Young

Young

FILTB E

bronzed

bronzed

bronzed

I. 1.." H
grti CIX‘L e 0

greckles.

grackle.

The seventh day.

The eleventh day.

The eleventh day.

PLATE 8

WWW

snacvza 1v3rw3H3 Sfuvaldux Hrn mu

am on NIH-43:35 numnm O'NOII-VUOdUOJ 11 IM. «on sunny..." 01' um
I
in”! H II I

 

 

PLLTE 2

Fig n. Three young bronged grackl

. es, ago 10 days,
in Ems t 2 et lrowbridge harsh. One is sittiig ir the cup
-of’ t1&,1:es1;, OIL; is ;,er<fi ed \fli tkuz rim: of .it, LJHJ thc>

third one in the but kgrcund is stretching a wing downward.
may 51 , 1952.; .

Fig. B. Th ee young bronzed grackles, age 1C do ye,
in Nest 25 ct Trowbridge harsh. All are f=u1n9 the Side
of the nest from which they are fed. Ma, 81, 1958.

PLATE 9

i . I! . I
It...»

9

\

 

Fig. A

 

 

 

 

PLAT .1: lb

Male grsckle with food at Nest 45 at Trom-
C

fiir. A.
brilge harsh stout to feed nine—duy-old nestling
lay 50, 195;.

Fig. B. Dead tree near Nest 25. The three birds in
the tree are:
(center) male rad—wing,
May so , 1952..

(uppermost) male grackle of Nest c,
uni (bottom) female of Nest 3-.

 

  

 

PLATE 1 O

 

 

 

 

 

“I my 1*.
- :1]. _I A.‘

g. A. Female bronzed grsnkie with a fecal sac
lcaVe Nest 25 at Trowbridge here}. May 50, 1952

i.
Cf
C-b FJ.
0

Fig. B Jezhele brrmze'l

. r;;kle witn heed below nine-
Cay-91” nestlings cleaning Nest :5. N“" 51, 195;.

 

 

PLATE 1].

 

('—

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hI;IIIIIIIIIIIIIIIIIII-I:_______________________________

 

 

 

 

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l
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