110

 

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SOME BIRD EANDING STUDIES AT
MICHIGAN STATE COLLEGE FROM
1924-1940 WITH SPECIAL REFERENCE.
TO THE WHITETHEGATED
SPARROW [ZONOTRICHIA ALBICOLLIS]
AND THE SLATE-COLORED JUNCO
[JUNCO HYEMALIS HYEMALIS]

Thesis for the Degree of M. S.
MICHIGAN STATE COLLEGE

Roger Lee Harned
I94!

 

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I5.- I

 

 

PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.

DATE DUE DATE DUE DATE DUE

 

 

 

 

 

 

 

 

 

 

 

 

MSU Is An Affirmative Action/Equal Opportunity Institution

SOLE BIRD BANDING STUDIES
AT MICHIGAN STATE COLLEGE FROM 1924 - 1940
mm SPECIAL REFERENCE TO
TIE RRITE-TRROAIRD SPARROW (ZONOTRICEIA ALRICOLLIs)
AND '
THE SLATE-C OLORED J‘UNCO (JURCO meme HYRMALIS)

by
'Roger Lee Earned

A THESIS
Submitted to the Graduate School of Michigan
State College Of Agriculture and Applied
Science in partial fulfillment of the
requirements for the degree of

MASTER OF SCIENCE

Department Of Zoology
East Lansing, Michigan
1941

\. HESXE

 

TABLE OF CONTENTS

I History of Bird Banding at Midhigan State
College ........................................
II Rbmhods of Recording Data ......................
III ‘White-throated Sparrows ........................
1. Number Banded Each Season, 1924 -
1940 ....................................
2. Record Of Repeats .......................
3. Migration Peaks .........................
4. Records of First and Last Captures ......
IV Slate-colored Juncos ...........................

1. Numher Banded Each Season, 1924 -

1940 eeeeeeeeoeee’ooeoooeecoeeeeeeeeeoeeeo

2. Record Of Repeats .00....CCCOOOOOCOOOOOOO.

3. Record Of Returns .......................
4. Migration Peaks .........................
V Comparison Of Migration Records ................
VI Study Of Bait Preferences ......................
1. method of Procedure .....................
2. Statement Of Results ....................

VII Bibliography .0000...0....OOOOOOOOOOOOOOOOOOOOO.

Page

17
22
27
32

32
35
41
44
54
57
57
58
65

Table I

Table II

Table III

Table IV
Table V

Table VI

Table VII

Table VIII

Table IX

TABLES

Number Of White-throated Sparrows
Banded by Spring and Fall Migrations,
1924 to 1940, Inclusive ................
Number Of'White—throated Sparrows

Caught Per Trap Day During Spring and
Fall ...................................
Number and Percent Of Repeats for White-
throated Sparrows During Spring and Fall
Migrations .............................
AveragePeriOd Of Repeats in Days for
White-throated Sparrows ................
mean Lengths Of Time Between Repeats in
Days, for White-throated Sparrows ......
unmber Of Slate-colored Juncos Banded
During Spring and Fall Migration, 1924
to 1940, Inclusive .....................
Number and Percent of Repeats for Slate-
cOlored Juncos During Spring and Fall
iMigrations, 1924 to 1933, Inclusive
Average Period of Repeats in Days, 1924
to 1933, Inclusive .....................

Average Number Of Repeat Days Per Indi-

vidual During Spring and Fall Migrations,

1924 to 1933’ Inclqu-ve 0000000000000...

10

l5

19

21

23

35

37

38

40

TABIES (Continued)
Page
Table X Return Records for Slate-colored Juncos
Banded at This Station, 1924 to 1939,
Inclusive ............................... 42
Table XI Numbers Of Catches Charted by Species
XII and Baits ............................... 62
Table XIII Tests for Significance Between First
XXIII and Second MOst Popular Baits by
Species ................................. 63
Table XXIV Tests for Significance Between First
and Second Mbst Popular Baits by

SPeCies 0.000000000000000000000000000000. 64

ILLUSTRATIONS
Igggg
Photograph Banding White-throated Sparrow ......... 3
Graph I Average Spring And Fall Migration
Curves For White-throated Sparrows
(1924 To 1939) ......................... 26
Graph II First Banding Records For‘White-
throated Sparrows During Spring Migra-
tion Periods (1924 To 1939) ............ 28
Graph III Dates 0f Last Banding Records For White-
throated Sparrows During Spring Migra-
tions (1924 To 1939) ................... 30
Graph IV Last Banding Records For'White-
throated Sparrows During Fall Migra-
tion Periods (1924 To 1938) ............ 31
Graph V Spring Migration Curves Charted By The
VII Percent Of Total.NUmber Banded In 3-Day
Periods (1928, 1929, And 1950) ......... 45
Graphs VIII Spring Migration Curves Charted By The
I; Percent Of Total Number Banded In 34Day
Periods (1932, 1933 And 1934) .......... 46
Graphs XI Spring Mflgration Curves Charted By The
XIII Percent Of Total NUmber Banded In 3-Day
Periods (1935, 1936 And 1937) .......... 47

ILLUSTRATIONS (Continued)

2353
Graph XIV Spring Migration Curves Charted By The
t Percent of Tota1.Number Banded in.3-Day
Periods (1938 And 1939) .................. 4e
Graph.XVI Average Spring And Fall Migration
(XVII Curves for Slate-colored JuncOs (1924
To 1939) ................................ 52
Graph.XVIII Average Spring Migration Curve For Slate-
colored Juncos Charted By The Percent Of
Total Number Banded In 3-Day Periods

(1932-193?) ooeooeeooeeeeeeeeeeoeeecoco 53

AC KN OYI'LED GIMAITS

The author wishes here to express his appreciation to
Dr; H. R. Hunt, first for suggesting this thesis, and later
for his able direction and kindly encouragement. TO Profes-
sor J.W. Stack also major acknowledgment is due for*supply-
ing the data upon which the thesis is based. His constant
and friendly cooperation was also most helpful.

mru Don.W. Hayne Of the Department Of Zoology supplied
many useful suggestions for presenting the subject matter,
and Dr. W. D. Baten of the Department of Mathematics extend-
ed valuable assistance on the statistical treatment of the
data.

TO the many others who gave of their time and experi-
ence in.the preparation of this manuscript the author also

wishes to express his appreciation.

HISTORY OF BIRD BANDINC AT MICHIGAN STATE COLLEGE

The bird banding station was first put in operation at
Michigan State College on October 12,.1923. On that date
Professor J. W. Stack placed the first bird trap in the
southeast corner of the Forest Nursery. Two more traps were
put in the wild flower garden by him in April, 1924. Three
more were set in the Forest Nursery September 30, 1924. Four
more were Opened in the Forest Nursery and immediate vicinity
in October, 1924. Four more were set on the campus during
the spring of 1925 and a fifth one in July of the same year.

During the fall term Of 1925 Professor Stack and meme
bers Of his advanced ornithology class operated the traps.
Interest was stimulated by giving students an opportunity
actually to band and handle living birds and the project
proved successful. While variations in.the plumage of indi-
vidual birds of the same species sometimes causes difficul—
ties in identification, constant use of a Barrows key to
Nfichigan birds was urged. Where students were still uncer-
tain of identification they were urged to consult Professor
Stack. Operation of the traps became a project of the class_
and time spent was accredited as a portion of the laboratory
work in the course. This method has been followed since
1925.

One advantage gained by having a number of Operators is
that the traps may be attended more frequently, thereby de-
creasing the possibility of injuries occurring to entrapped
birds.

2
Until the fall Of 1938 the bulk Of trapping Operations,

except for the special projects Of individual students, was
carried on in the Forest Nursery and in the Deal Botanical
Gardens, the traps being almost equally divided between the
two areas. During the Spring of 1938 sanctuary rights were
granted for an inclosed area just west Of the Old rodent
laboratory along the north bank of the Red Cedar River direct-
ly south.of Wells Hall. In the fall Of 1938 the bird traps
were shifted to this area and have remained there. It is Pro-
fessor Stack's intention to keep this site as a permanent
bird banding area and to keep the number, type and location
of traps constant in order to reduce the variables and to
make future date more significant. The area, with its in-
closing fence, alSO'Will discourage wandering catsand dogs,
and eliminate the disturbing influences of a crowded campus.

The type Of trap which has proved.most successful and
which has been used almost exclusively is the modified gov-
ernment sparrow trap described in the "Manual for Bird Band-
ers" by F. 0. Lincoln and S. Prentiss Baldwin. It was orig-
inally designed, after extensive experimental work, by the
late W. I. Lyon Of waukegan, Illinois.

Another highly successful method of catching birds at
this station has been by means Of Italian bird nets.* Ital-

 

FThese Bird Trammel Nets are 20' long by 7' high, outside
netting 10" square mesh #16 cotton twine; inside netting %"
square mesh #50/2 linen; are hung with #24 twine at top and
bottom with small black metal rings 2" in diameter; these
are attached to the top with 2" lengths of #12 medium.twine.
The nets are dyed black, this color being least conspicuous.

BANDING-WHITE-THRQATED SPARROW

 

 

 

Photographed by Lloyd Hulbert at the
Michigan State College Bird Banding
Station. '

ians made use Of these nets in capturing large numbers Of
birds for food purposes before decreasing numbers prompted

the government to put a stop to their slaughter. Dr. 0.L.
Austin, while visiting in Europe, conceived the idea of us-
ing the nets for banding purposes and brought one back to

this country for experiment. It proved successful and nets
were imported from.Italy for use in this country, though at

an exorbitant 80% tariff rate, up to the beginning Of the pre-
sent war.

Dr. Austin visited this station some eight years ago. He
set one of his nets in the forest nursery for a trial and in
less than an.hour several birds were caught. Since it was
impractical to pay the price Of importing nets from Italy, a
description Of the nets was sent by Professor Stack tO the R.
J. Ederer Company Of Chicago, manufacturer of commercial fish
nets. As a result this company has been supplying the nets
for the past eight years.

In 1932, as an experiment, four nets dyed green, four
nets dyed a gray dust color, and four dyed black were used.
All were set under conditions as nearly similar as possible.
It was found that the black type Of net was most successful.
It was also learned at that time that nets soaked in creo-
sote before using and allowed to dry thoroughly had a longer
life without in any way presenting a greater risk Of injury
to birds. These nets have been in Operation at this station
since 1932 with as many as 24 having been in use at one

time .

5

Several other types of traps have been used, with vary-
ing degrees of success. For a period of three years a very
elaborate house trap was employed. It proved to be the least
successful type Of trap used at this station, though at St.
Paul, Minnesota, Mr. and Mrs. F.W. Commons report having
found it to be very effective. From 1937 to 1940, two duck
traps were operated at Lake lensing, approximately eight
miles northeast of East Lansing on State Road # 78. The
traps were located on.the east side of the lake. During the
three years many Species and individuals were taken.

An Inland Creeper Trap*has been successful for trapping
DownnyoOdpeckers, Brown Creepers, Black and'White Warblers,
and'White-breasted Nuthatches. A nest-drop-door trap has
been used for capturing:the parents of nestlings for banding
purposes. Many pairs Of Prairie Horned Larks have been
banded in this manner as well as parents of Mburning Doves,
Robins, and Chipping Sparrows. Bank Swallows have been
handed successfully by means Of insect nets or Italian bird
nets, attached to the ends of bamboo poles, placed over nest
entrances. Italian bird nets are particularly useful when
several nests occur in banks in a small area. The Cohasset
Warbler trap has never been found satisfactory at this sta-

tion.

 

”TFOr descriptiOns of‘different types of;traps used, see,
"manual For Bird Banders" by F.C. Lincoln and S. Prentiss
Baldwin, 0.8. Department of Agriculture, Miscellaneous Pub-
lication.NO. 58, November, 1929.

METHODS OF RECORDING DATA

This work is mainly a compilation Of data collected by
Professor Stack and his advanced ornithology class over a
period Of 17 years. A description Of the records and the
method Of keeping them is in order.

The first record for each bird is made out by the band-
er as a field note. This note contains the name Of the
bander, the time Of day, the number Of the band placed on.the
bird's leg, the common name of the bird, whether the capture
was made in a net or a trap, and any Observations Of injury,
plumage variations or peculiar behavior. If the bird has pre-
viously been banded it is recorded as a Repeat or a Return.

A bird is considered a return if a period greater than 6 mon-
ths has elapsed since the date Of the last capture. If the
period is less than a half year, the bird is called a repeat.

Back at the station Office, where all materials such as
banding kits, bait, and a key tO Nflchigan birds may be found,
the bander first checks a list posted on the wall containing
all the numbers of bands which have been placed on birds since
1923 to determine whether the birds he has captured are repeats
or returns. Traps and nets are usually visited every hour
to reduce the danger Of injury to birds.

O Field records are entered chronologically in a journal,
a single journal usually containing records for a single mi-
grating season. The band number, the common name, the date
of capture, and.the name of the bender of each bird are then

transferred from the journal to an individual card and placed

in a fireproof metal file in chronological order. In this
catalogue species are separated by index cards containing
scientific names and the A. 0.‘U. Check-List of North Ameri-
can Birds, (fourth edition). Numbers are kept to facilitate
location Ofspecies.

A.separate file is kept for returns. A notation and ref-
erence to "Return File" is made on each original card for
which a return.has been recorded. Return cards give the
dates Of returns, the localities, the nanes and addresses of
the persons recovering birds in cases Of recoveries at fore-
ign stations, and spaces for remarks on.the condition of
birds, and.the manner taken. Of course, much of the original
banding data, such as band number, common name of species,
trap number (when known), date Of original capture and name of
bender is included at the top of each card.

A death and longevity file is also kept in the same man-
ner in which species are separated by index cards containing
A. 0.‘U. check list numbers in serial order. NOtations on
any bird banded here and subsequently found dead or reported
dead are entered in.this file. This is the only manner known
at present by which.we may learn anything about how long birds
live. To obtain more accurate infbrmation on longevity, nest-
lings have been banded.whenever it has been safe to do so.

The number of each species banded is recorded by'months
on a special form. This form is one Of a number of the con—
tributions made by'W. I. Lyon as an aid to systematizing
station records. It has been used at the Mighigan State Col-

lege bird banding station since 1923. Its use has contri-
buted substantially to the information found in this thesis.

WHITE-THROATED SPARROWS

The White-throated Sparrow is one Of the most abundant
members of its large family. It breeds in Canadian and low-
er Hudsonian zones, and Spends its winters in Missouri, the
Ohio Valley, southern Pennsylvania, Connecticut and mass-
achusetts. It is caught at this station in larger numbers
than any other bird, except only the Slate-colored Junco, on
its migratory routes between its summer and winter homes.

A total of 4,174 White-throated Sparrows were banded for
the years 1924 to 1940, inclusive. Of this number, 2,712
were banded during spring migration periods and 1,462 during
fall migrations. These figures are indicative Of the varia-
tions in spring and fall migrations though it should be
noted that no banding was done during the fall Of 1930, and
that therefore the totals include one more set Of spring
than fall figures. The actual number banded each spring and
fall for the seventeen year period is Shown in Table I.

The mean yearly number of birds banded during fall mi-
gration periods was 91.4. The average number banded during
spring periods was 159.5. A difference as great as 68.1
would occur by chance about once out of twenty times. There-
fore the difference is significant:

In considering this difference some attention might be
given to a series of factors that has not been constant dur-

ing the period. The traps covered in this work have only

TABLE I

norm-SR 0F IRIITR-IRROATRD SPARRO’I’IS 1321mm)

YEAR

1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936

1937
' 1938
1939
1940

BY SPRING AND FALL IvIIGRATI CNS ,

1924 TO 1940, INCLUSIVE.

SPRING FALL

................. 75
................. 33
................. 122
................. 203
................. 135
................. 236
................. 136
................. 86
................. 170
................. 240
................. 204
................. 198
................. 124
................. 180

0.000000000000000 202

0.000000000000000 246

0.000000000000000 122

TOTAIS 0000000000000. 2712

.............. 39
.............. 91
.............. 111
.............. 87
.............. 164
.............. 110

00000000000000 28

00000000000000 168

0000000000000. 60
0000000000000. 38
0000000000000. 30

.............. 148
.............. 134
.............. 104
.............. 105

00000000000000 45

0000000000000 1462

10

11

been operated during the school year which varies according

to the opening and closing dates of the College; the number

of traps operated increased largely during the early years

of the study and has since fluctuated for various reasons;
several changes in.topography and cover of the campus has
made it necessary to shift trapping locations in order to ob-
tain the most suitable habitat for trapping. It is conceiv-
able therefore, that considerable variation.might occur in the
number of birds caught durinngigration periods.

In order to study further the variation existing between
the numbers banded in spring and fall, a.mathematical formula
has been devised in an attempt to control two of the princi-
pal factors which would contribute to flie'variation. These
two factors are: first, the number of traps, and second, the
length of time each was operated. This formula is based
upon the assumption that the traps were located in equally
suitable locations from.season to season, and therefore, the
number of birds caught would vary in proportion to the numr
ber of traps used and the length of time each was in operation
during the migration periods. Results are expressed as the
average number of birds caught each trap day and are calcu-
lated by dividing the total number of birds caught during the
migration season by the total number of trap days. For ex-
ample, in the spring of 1928 twelve traps were Operated for
a period of nine days and caught 25 birds, 16 other traps
were Operated by another person for a period of 20 days and
caught 46 birds, also 14 more traps were operated for a
period of 20 days and caught 64 birds, thus making a total

12
of 135 birds caught in 708 trap days, or 0.10 birds per trap

day. Birds caught per trap day therefore equals the total
number of birds caught per migration season divided by the
number of traps times the number of days operated.

Table II shows the number of birds caught per trap day
for the years 1924-32, inclusive. Records of individual traps
were not kept after 1932.

The average number banded per trap day during spring mi-
grations was 0.27 with a standard deviation of 0.20. The av-
erage number banded per trap day during a fall migrationxnas
0.15 with a standard deviation of 0.06. The difference be-
tween the two averages is significant. It would occur by
chance about once out of twenty times.

It was impossible to treat the entire banding data by
the trap-day method because records of the exact number of
traps used and the number of birds caught by individual traps
were kept only from.l924 to 1932.

The above data raises an interesting question in measur-
ing migration intensity. Is there always a definite relation-
ship between the number of birds caught and the number of trap
days? It is apparent from.the facts given.that usually a re-
lation does exist, but at the same time it is not evident that
an absolute correlation can always be relied upon. For ex-
ample, in the fall of 1926, 117 birds were caught in 690 trap
days, whereas in 1927 only 83 birds were caught in 841 trap
days. In other words, in the fall of 1926 more birds were
caught in fewer trap days than in 1927. The correlation over

a period of eight years, however, was found to be 0.64.

TABLE II

NUMBER OF WHITE-TEROATED SPARROW?) CAUGHT

PER TRAP DAY'DURING SPRING AND FALL MIGRATIOES

YEAR

1924
1925
1926
1927
1928
1929
1930
1931
1932

SPRING

0.81
0.09
0.16
0.23
0.19
0.30
0.23
0.14
0.29

00.00000000000000

oooooooooo‘ooooo.

FALL

0.15
0.15
0.17
0.10
0.21
0.20

0.08
0.16

13

The total number banded in.spring was found both in 14

total figures and trap day calculations, to be significantly
greater than the total number banded during fall migration
periods.

It might be expected that greater numbers would be band-
ed during the fall because that period would include not only
the mature birds but also the young of the year. Then too
it has been.3hown that the fall.migration.period is more
leisurdw, that is, it extends over a longer period of time.
The average spring migration period is about one week shorter
than the average fall period. Therefore it might seem that
this would increase the chances for each bird to be captured
and as a result the total catch.would be greater during the
fall.

It is evident that the above statement presents only one
side Of fine question and that the following factors should be
considered.

First, since natural food for ground feeding Species,
such as the White-throated Sparrow, is more abundant during
the fall migration season it seems natural to expect that
fewer birds would be attracted to artificial baits during
that period. Therefore it is probable that a greater catch
would be realized during the spring period Which usually be-
gins around April 20 and ends about May 20.

Second, contrary to popular Opinion all birds do not
seem.to follow the same migration routes from.year to year
or even the same routes in spring and fall. Especially does
this seem to be true for'the White-throated Sparrow. Ac-
cording to all information at hand, at stations between win-

15

ter and summer homes, local return records for‘White-throated
Sparrows are rare. Mr. F. 0. Lincoln2 of the Fish and Wild-
life Service, 1935, makes the following statement about this:

"The‘White-throated Sparrow is a common.migrant
in.many sections. Since it is a ground-feeding bird
and is readily attracted to the vicinity of dwellings,
it has been banded in large numbers, the total to
February 1, 1935, being nearly 100,000. It would be
expected that these would yield a comparable number
of return records, and that the facts would furnish
basic data relative to the migrations of the species.
Such, however, is not the case. Banded'White-throat-
ed Sparrows are rarely recaptured at stations be-
tween the breeding and.the wintering grounds. Opera-
tors Of stations in.the winter area, as Thomasville,
Georgia, (8. Prentiss Baldwin) and Summerville,

South Carolina, have obtained return records showing
that these birds do come back to the exact winter
quarters occupied in previous seasons. The fact
that they do not again.visit banding stations on
their migration routes indicated some unusual as-
pects of their travels, which it is hoped will ev-
entually be discovered by banding studies. Problems
of this type constitute definite challenges to the
student of bird migration."

mr. Lincoln2 also says: "The'White-throated Sparrow, a
bird that apparently breeds and winters each year in the same
areas, either travels by different routes, or at least does
not make the same stops while on.migration."

The only information which has been Obtained about a
bird of this species banded at this station came from.E1dor-
ado, Arkansas. This bird was banded here April 27, 1927,
and was Shot by T. meoty at Eldarado in.NOvember, 1929. This
bird was evidently shot while on.migration or at its winter
home .

Third, it is possible that in some years we do not get
the earlier days of fall migrations since the date Of Opening

the trapping station depends upon the opening dates Of school.

16
Fourth, light days are somewhat longer during spring mi-

gration. Whether this difference is great enough to cause an
appreciable difference between the numbers banded during the
two seasons is questionable but it might be considered as a
contributing factor.

Something more should be said, however, concerning the
variations which occur in the numbers banded within the same
season from year to year. These differences are due to a
combination of several factors which may be summarized as fol-
lows:

First, that 'u‘Jhite-thmated Sparrows do not follow the
same migration routes from year to year, or at least do not
make the same stOps.

Second, is the effect of variations in climatic condi-
tions. Mr. Lincoln6 has said that the migration of birds has
so evolved that in general they synchronize with average cli-
matic conditions. Also, birds pause during migration and al-
low the Spring season to advance, and then by rapid travel a-
gain overtake, and sometimes even overlap it. Possibly great
flocks sometimes congregate in a locality until favorable con-
ditions prevail and then by non-sto p flying pass over many
localities along their migratory route. Perhaps this parti-
ally explains why White-throated Sparrows do not make the same
stops from season to season.

Third, according to Bradt7 there seem to be differences
in trap-shyness among individuals. He observed that within
the same species certain flocks were readily attracted to the

vicinity of traps and were caught with regularity, whereas

17

other flocks seemed to be more wary and therefore were sel-
dom caught. But, of course, this theory involves bird psy-
chology, a field in which little is known and about which
little can be said in this work.

Fourth, it has been shown that there is a positive cor-
relation between the number Of trap days and the number Of
birds caught. Therefore, the variation from year to year
would depend on the number of traps used and the number of

days they were Operated.
Record 3; Repeats

A bird which is recaptured at the same station within a
period of six months after the date of the last previous cap-
ture is called a repeat. This teminology is based on the
theory that if only a short period of time elapses between
captures it is probable that the bird has remained relatively
close to the station between captures. The period of six mon-
ths has been fixed arbitrarily to correspond with‘the length of
the migrating season. If a period of time greater than six
months elapses between catches, the bird is classified as a
local return.

A great many things may be learned from studying the re-
peats of birds. The length Of stop-over periods along the
migration route, the tendency of species to form the trap-
habit method of feeding, the length of time elapsing between
repeats, the relation of frequency of repeats to weather con-
ditions, and the comparison between the repeat records of

different species and between individuals of the same species,

18

are all problems which may be studied from repeat records.
The White-throated Sparrow acquires the trap-habit readily
and repeats with regularity. One'White-throated Sparrow re-
peated 55 times in 38 days.

The average percent of repeats during spring migrations,
as determined from Table III, is 24.6 with a standard devia-
tion of 14.5. The corresponding average for fall migrations
will be found to be 63.3 percent with a standard deviation of
15.6. The difference between the two averages is significant.
This difference would occur due to chance about one time out
of twenty.

BradtV, whose results were based on banding results for
only one year, did not find a significant difference between
the number of repeats in spring and fall.

The difference shown.in this work from.records over a
period of ten years, is probably due in part to the fact that
migration in the fall is more leisurely. Assuming birds do
remain in one locality for a longer period of time in the fall
than in the spring, it would be expected that they would be
taken a greater number of times in the fall.

According to Rowan3

a greater speed of migration in.the
spring is due to a strong urge for mating and reproduction.
This urge, not being present in the fall, would cause migra-
tion to be less rapid.

It might be thought that since natural food is more
abundant during the fall period, fewer birds would be in-
clined to form.the trap-habit. This does not hold true for

repeating White-throated Sparrows at this station.

19

TABLE III

NUIBER AND PERCENT OF REPEATS
FOR.WHITE-THROATED SPARROWS
DURING SPRING AND FALL MIGRATIONS

 

 

YEAR SPRING : FALL

Number Number Percent : number Number' Percent

Banded Repeats Repeats : Banded Repeats Repeats
1924 75 10 7.5 : 39 28 71.8
1925 33 10 3.3 : 91 48 52.8
1926 122 23 18.8 : 111 74 66.6
1927 203 83 40.8 : 87 37 42.5
1928 135 37 27.4 : 164 122 74.4
1929 236 117 49.6 : 110 75 68.1
1930 136 22 16.2 :
1931 86 37 43.0 : 28 26 92.9
'1932 170 48 28.2 : 168 63 37.5
1933 240 26 10.8 :

20

Table IV shows the average length of stop-overs in days
for birds that repeated during spring and fall migration per-
iods. Period of repeats in days as used in this table is de-
fined to mean the average number of days which elapsed from
the first day a bird was taken to the last day it was taken,
inclusive.

The average days in this locality for birds Which repeat-
ed during spring migrations was feund.to be 4.5 days, with a
standard deviation of 1.57. The average for fall migration
was 10.67 days, with a standard deviation of 2.56. The dif-.'
ference between the two averages is significant. This differ-
ence would occur by chance about once out of twenty times.
Bradt7 found evidence Which indicated a more leisurely pass-
age south in the fall but did not prove it definitely due to
insufficient data.

These results seem.to substantiate the hypothesis stated
before, that a greater number of repeat records Should be ex-
pected during a fall migration period because during that per-
iod'White-throated Sparrows remain in this locality for a
greater length of time.

In order to compare the length of time between indivi-
dual repeats during the two seasons a formula has been de-
vised. The average length of stop-overs when divided by the
average number of repeats for that season equals the average
time between repeats during that particular season. For ex—
ample, in the spring of 1924, the average stop-over period

‘was 3.2 days. The average number of repeats for’that sea-

YEAR

1924
1925
1926
1927
1928
1929
1930
1931
1932
1933

TABLE IV

AVERAGE PERIOD OF REPEATS IN DAYS

FOR WHITE-THRO

SPRING

3.2
3.0
4.4
4.8
4.1
6.9
3.4
8.4
5.2
4.3

D SPARROWS

Egg;
13.2
12.5
11.2
16.4

7.5

8.9

13.8
11.9

21

22
son was 2.3 times. The quotient is therefore found to be

1.39 days. In other words, for White-throated Sparrows
that repeated, an average time of 1.39 days elapsed between
recaptures. Table V shows the results of these calcula-
tions.

The average time between repeats during spring migra-
tions was 1.94 days, with a standard deviation of 0.50. The
average for fall migrations was 1.70 days with a standard
deviation of 0.24. The actual difference between the aver-
ages was therefore 0.24 days. This was found to be only 0.7
times the standard error of difference between.the two means
and is therefore insignificant. It is probably due to
chance alone.

These results seem.to indicate that: (1) the inclina-
tion to repeat is equally great in spring and fall; (2) sea-
sonal difference in food conditions is a relatively unim-
portant factor influencing the number of repeats; and (3)
the greater number of repeats in the fall is chiefly due to
the longer stay in the locality during that migration period.

Migration Peaks

It is difficult to say that a migration reaches its
greatest intensity on any one specific day because the num-
bers caught on.succeeding days may vary greatly. In order to
show a somewhat smootheerigration curve and still give the
impression of the fluctuating tendency it seems better for
all practical purposes to group the number of birds banded in

two or’three days. For'thiS'work a three day period has been

MEAN LENGTHS 0F TINE BETWEEN REPEATS, IN DAYS,

1925
1926
1927
1928
1929
1930
1931
1932
1933

TABLE V

FOR.WH

SPRING

E-THRO ATED SPARR OWS

1.39
2.31
1.83
1.85
1.78
2.15
1.36
1.35
2.48
2.87

FALL

1.50
1.64
1.67
1.83
1.92
1.24

1.68
2.09

23

24
adOpted. Bradt7 used a fifteen day period.

In general the peak of spring migration was found to
fall somewhere between the first and ninth of Hwy; and.most
frequently between the first and third. During five periods
the peak occurred from the first to the third, for four years
thepdnhacle'was reached from.the fourth.to the sixth, during
three seasons the period of maximum intensity came between
the seventh and ninth, in one period the peak fell from.May
tenth to twelfth, during one year it occurred from may thir-
teenth to fifteenth; and for one period the peak was from
the twenty—eighth to the thirtieth of April. The spring peak
for 1933 could not be included in the above classification
because that was an exceptional year having two peaks. Six-
ty three birds were banded from the twenty-eighth to the
thirtieth of April and sixty-three were also banded from.the
seventh to the ninth of may. Between these two peaks, may
the first to sixth, nine birds were banded. This example
clearly illustrates an extreme fluctuation. Such fluctua-
tions may be due to changing climatic conditions, variations
in temperature and the occurrence of local storms.4

In general the peak of fall migration was found to occur
from.the first to the sixth of October,inclusive, and.most
frequently from the first to the third. During three years
the peak occurred from.the first to the third of October, for
two seasons the pinnacle was reached between.the fourth and
the sixth of October, in two fall migrations the period of
maximum intensity came from.the seventh.to the ninth of Oct-

ober, and in two periods the time of maximum banding activi-

25
ty was between the tenth and.the twelfth of October. For

the years 1926, 1932, 1934, and 1936 it was impossible to de-

termine single three day periods in Which the greatest numbers

of birds were banded.

For all years, with.the exception of perhaps 1931, mi-
gration did not reach a peak before banding operations began.
Therefore, the relatively late dates for the opening of col-
1ege did not prevent us from.determining the period of maxi-
mumflmigration.

Graph I presents the spring and fall.migration curves for
'White-throated Sparrows. Each point on the curves is the av-
erage number of birds banded on three successive days over a
period of sixteen years. These curves may be used in the fu-
ture as standards for comparison.with curves for individual
years.

An inspection of these graphs leads to the following gen-
eral conclusions concerning spring and fall migrations of
White-throated Sparrows:

1. The bulk of spring migration occurs between the
ninteenth and twenty-first of April and the ninteen-
th and twenty-first of may, a period of thirty-three
days.

2. The bulk of fall migration comes between the twenty-
sixth and twenty-seventh of September and the twenty-
fifth and twenty-seventh of October, a period of thirh
ty-three days.

3. The average spring migration peak falls between the
seventh and ninth of may, inclusive.

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27

4. The average fall migration peak occurs between the
first and third of October, inclusive.

5. After:migration begins the peak is reached in less
time and is more abrupt in.the fall than.in.the
spring. After the peak is reached, migration term-
inates in less time and the slope is more abrupt
during the spring.migration. This further supports
the theory that there is a definite urge in.the
spring to reach breeding grounds. This urge is non-
existant in the fall and migration is more straggling
and leisurely.

6. The difference between the average numbers banded in

the spring and in the fall is clearly Shown.

The first and last captures of birds for both spring and
fall migration seasons are of particular interest for several
reasons. The first arrival of birds in.the early months of
the year, for example, is always welcomed because of their as-
sociation with approaching spring. likewise, it is always with
regret that we record their departure in the fall as a warning
that winter is on the way.

Graph II shows the dates of the first banding of White-
throated Sparrows for each.of the years from.1924 to 1939.

The earliest date recorded is April 17th and the latest is
April 30th. The average date is April 23rd and the average

deviation would be approximately three and one-half days. It

 

29
is interesting to note, over a period of sixteen years,

that this deviation is no greater.

Graph III shows the dates of the last banding for each
of the same years. The last date recorded is May 27th and
the first date is may 8th. The average date is may 19th,
and the average deviation is four and one-half days. The
average spring migration as revealed from the spread of
dates between Graphs II and III covers a period of twenty-
seven days, with a.mean deviation of eight days.

Graph IV'Shows the dates of the last banding of White-
throated Sparrows for each of the:years from 1924 to 1939.
The last date of capture was November 8th and the first date
was October 13th. The average date would be between Octo-
ber 27th and 28th with a.mean deviation of seven days, which
is greater than.the deviation in either spring arrival or
departure days. Departure in the fall is not hurried by the
strong migratory stimulus that exists for a spring departure.

It was not possible in this study to consider first ar-
rivals in.the fall migration. This is due to the fact that
in most of the years covered migration had already begun be-

fore school was open and the traps put into operation.

 

 

32
SLATE-C 0LORED J'UNCOS

The Slate-colored Junco is a small, plump, bird common-
ly known as the "snow bird". It comes at a time when most
of the other birds have left for their winter homes in.the
south, and usually remains until late in.the fall. It breeds
in the Hudsonian and Canadian zones in northwestern Alaska,
northern mackenzie (the tree-limit of North America, northern
Imanitoba, central Quebec, the base of'the Alaskan peninsula,
southern.Yukon, central Alberta, northern.Mfinnesota, central
Michigan, Ontario, and the mountains of New York, Pennsylva-
nia, and.Nmssachusetts. Its winters are spent in the east-
ern.United States, southern Ontario, and south to the Gulf
Coast. These birds are banded at this station in greater
numbers than any other Species. They are taken almost en-
tirely during their migratory periods since relatively few
remain in this locality throughout the winter months. For the
period of 1924 to 1940, inclusive, 5349 were banded. If the
total number of repeats were added to this, the total number

of catches would approximate 12,000.

Number Banded Each Season 1924-40

Of the total number banded, 2236 were banded during
spring migrations and 3133 during fall migrations. In Table
VI the numbers are shown both by years and seasons. 1

The mean number banded during spring migrations is 131.5
with a standard deviation of 86.6. The average number in the

corresponding fall migrations is 195.8 and the standard de-

1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940

TABLE VI

NUMBER OF SLATE-COLORED JUNCOS

BANDED DURING SPRING AND FALL MIGRHI‘I ONS,

1924 to 1940, INCLUSIVE.

SPRING

6

'7
ea
52
280
119
151
17
22:5
146
249
252
105
137
318
146
43

153
199
330
151
285
335

78
368
155
155
215

71
131
266
185

36

33

34
viation is 100. The difference between the means, 64.3, is

not significant since it would occur through chance about one
in five times.

One explanation for this dissimilarity is that in some
years springznigration begins before the traps are Opened.
The beginning of spring trapping operations at this station
corresponds roughly to the Opening date of the spring term.
The trapping station has therefore started from.April 4th to
April 16th during the past sixteen years. This variation
would make a considerable difference in the number captured,
since the maximum.migration period often falls in the period
of April 7th to April 12th. Also it is difficult to deter-
mine the actual start of migration at this station because oc-
casionally individuals do winter in this area. Journals from
students doing Special problems during the winter terms show
records of a few Slate-colored Juncos caught throughout the
winter months. Bradt7 found spring migration.beginning on
April 9th.

Another probable theory to account for’the difference is
as follows. It has been aiown.that spring migration is usual-
1y more rapid mien.fall.migration. This difference has been
said to be due to the presence of the strong urge in the
spring for mating and reproduction. This urge is associated
with the growth and development of gonads in the spring,
initiated by increasingly longer light days and a greater a-
mount of activity. It might be that when.favorable weather

prevails in.the spring, birds make a series of extremely long,

35
non-stop, flights until they reach their destinations in the

north. Since this is not present in the fall, migration may
be less rapid and stop-overs made oftener and for greater
periods of time. If this is true, it would seem partially to
account for the smaller number banded in the spring.

An examinatiOn of Table VI reveals an interesting point.
The total number of Juncos caught during spring and fall mi-
gration before 1932 is almost equal. The total for fall
migration is 1214 and the corresponding total for spring mi-
gration is 1293. It is evident that the difference is not
significant. Then why is there a difference since 1932? It
is noteworthy that bird trammel nets were first employed as
a supplementary method of capturing birds in 1933. It may be
that this factor has played an as yet unrevealed influence in
the change. A more likely reason, however, would seem to be
that captures of Slate-colored Juncos have always been rela-

tively heavy in the fall.
Record 2;; Repeats

Several interesting things about the behavior of Slate-
colored Juncos in migration can be learned from a study of
their repeating habits. The repeats of these birds, that is,
their recaptures within a period of six months after original
captures, show the length of their stop-overs, the tendency
to form the trap habit method of feeding, and the length of
time elapsing between their repeats. The number and percent-

age of repeats in comparison to the total number banded is

36
shown for both spring and fall for the years 1924 to~l933

in Table VII.

The average percent of repeats during spring migrations
was found to be 29.57 with a standard deviation of 16.5. The
average for fall migrations was 42.6, with a standard devia-
tion of 19.4. The difference between these two averages
(13.1) is not significant. A difference as great as 13.1
would occur throigh chance approximately once in.three times
so this difference may be due to chance.

The percent of spring repeats for Slate-colored Juncos
(29.5) is slightly greater’than spring repeats for'White-
throated Sparrows (24.6) but the difference is not signifi-
cant. The percent of fall repeats for‘White—throated Sparrows
(63.3) was found to be significantly greater than the percent
of fall repeats for Slate-colored Juncos (42.6). The differ-
ence (10.7) would arise from.chance once in twenty times.

This indicates a greater tendency for‘White-throated Sparrows
to form the trap habit during the fall migration.

In Table VIII the period of repeats in days is defined to
mean the average number of days which elapsed from.the first
day a bird was taken to the last day it was taken, inclusive.
The table shows the repeat periods for both spring and.fall
seasons from.1924 to 1933.

Let us look at these repeat periods, compare them for
spring and fall, and see What they mean. The repeat periods
for spring vary from.a.minimum of five days in 1933 to a.maxi-
mum of sixteen days in 1927. The average period was 9.7 days
with a standard deviation of 3.1. The repeat periods for fall

TABLE VII

NUMBER AND PERCENT OF REPEATS FOR SLATE-COLORED JUNCOS
DURING SPRING AND FALL MIGRATIONS;
1924 - 1933 INCLUSIVE

 

 

YEAR SPRING FALL

Number Number Percent : Number Number Percent

Banded Repeats Repeats : Banded Repeats Repeats
1924 6 2 33.0 : 153 28 18.3
1925 7 O 0.0 : 199 83 41.7
1926 88 26 29 .5 : 330 119 36 .0
1927 52 28 53.8 : 151 73 48.3
1928 280 100 35.7 : 285 84 29.5
1929 119 36 30 .2 335 187 55.8
1930 151 71 47.0 : O O 0.0
1931 17 0 0.0 : 78 68 87.0
1932 223 68 30 .5 : 368 88 23 .9
1933 146 52 35.6 :

TABIE VIII

AVERAGE PERIOD or arrears IN DAYS,
1924 - 1933, INCLUSIVE

z§g3_ SPRING 2gp;
1924 6.0 10.3
1925 17.9
1926 9.8 12.5
1927 16.0 18.8
1928 9.2 14.3
1929 11.4 9.3
1930 10.5

1931 11.2
1932 9.6 14.2
1933 5.0

39
run from a minimum of 9.3 days in 1929 to a maximum of 18.8

days in 1927. The average was 13.6 days with a standard de-
viation of 3.2. It will be seen that the repeat periods for
fall are considerably longer than those for spring. The dif-
ference between the two averages, 4.9, would occur through
chance only once in twenty times and is therefore consider-
ed significant. It is particularly significant in this in-
stance. Since the time covered by the average period of re-
peats is a relative indication of the length of time birds
remain in a locality, it would mean that birds remained at the
college banding station for a greater number of days in spring
than in fall migrations. In other words, migration during the
fall is more leisurely than during the spring.

In Table VIII we studied the length of time Spent in this
locality by migrating Slate-colored Juncos in Spring and fall.
We are now prepared to study the number of times repeating
birds are caught. 18 the number related to seasons? In Tab-
le IX the average number of days that individuals repeated
is shown by years and by seasons from 1924 to 1933.

The number of repeat days in spring migrations vary from
a minimum of 1.00 in 1924 to a maximum of 4.21 in 1927. The av-
erage is 2.9 with a standard deviation of 0.98. Repeat days
in fall vary from a minimum of 1.89 in 1924 to a maximum of
4.24 in 1925. The mean is 3.1 repeat days with a standard
deviation of 0.75. The difference between these two means is
not significant. We may then conclude that there is no sig—

nificant relation between the number of repeat days and sea-

sons 0

TABLE IX

AVERAGE NUNEER GE REPEAT DAYS PER INDIVIDUAL
DURING SPRING AND FALL NIGRATIONS,
1924 - 1933, INCLUSIVE

gpgg_ SPRING 3gp;
1924 1.00 1.89
1925 4.24
1926 2.19 2.64
1927 4.21 4.09
1928 3.20 3.02
1929 4.19 3.43
1930 3.07

1931 2.97
1932 2.81 2.45
1933 2.50

41
Record g§_Returns

The question.of’whether or not birds follow the same
migration routes in different seasons has been long debated.
The chance that the same bird will return to exactly the same
banding station on its migratory route,usually hundreds of
miles in length, seems to be extremely small. Fourteen re-
turn records have been recorded for Slate-colored Juncos
banded at this station. These records furnish the only evi-
dence that these birds follow the same migratory routes dur-
ing different seasons.

Table I is a record of returns. It shows the number of
the band on the bird's leg, the dates of original capture,
and the dates of recovery for the fourteen birds. It may be
noted that nine of the records are of birds banded original-
ly during fall.migrations. All were recaptured during the
succeeding Spring migrations. Only one of the birds, Num-
ber B 19,537, returned in any subsequent migrations. This
bird returned twice and is the only Slate-colored Junco some
ing back more than once to this station! The records of birds
bearing bands numbered 34-6962, 34-6963, and 34-6964 and birds
bearing band numbers H 90,910 and H 19,537 are particularly
interesting. Birds with the first three band numbers were
caught on the same day, October 24, 1936. Two of the three
were retaken again.the following spring on the ggme day, A-
pril 14, 1937. The third was recaptured two days earlier,
April 12. Birds with band numbers H 90,903 and H 90,910 were
both originally caught October 30, 1934 and both returned the

TABLE x
RETURN RECORDS FOR SLATE-COLORED JUNCOS
BANDED gr grips STATION
(1924 - 1939)

 

 

 

BAND NUEBER ORIGINAI.CAPTURE RETURN

34-6962 October 24, 1936 April 14, 1937.

34-6963 October 24, 1936 April 14, 1937

34-6964 October 24, 1936 April 12, 1937

0 30,343 October 5, 1932 April 19, 1933

F 78,312 October 14, 1932 April 11, 1933

F 79,290 October 19, 1937 April 8, 1938

H 90,903 October 30, 1934 April 6, 1935

R 90,910 October 30, 1934 April 6, 1935

B 19,537 October 2, 1929 march 27, 1930
April 18, 1931

A 89,923 April 6, 1927 November 11, 1927

B 19,302 April 27 1928 November 4, 1928

0 30,207 October 27, 1929 October 6, 1932

A 92,232 October 9, 1928 October 3, 1929

B 20,662 April 15, 1 1928 April 12, 1929

43
same day, April 6, the following spring. These examples

are noteworthy because they raise an interesting question.
Do Slate-colored Juncos remain in flocks throughout the wins
ter? It is indicated from.the records that they do remain
united throughout the winter. This is even.mere amazing
when one thinks of the many hazards of migration. It is not
evident whether or not this is a rule or an exception.

Two birds were banded while traveling north in spring
migrations and returned to our station.the following fall dur-
ing their flight south. The greatest period of time elapsing
between captures for returned birds is approximately one year.
Four such records are Shown in Table X.

The two most salient points shown by these return re-
cords are : (1) No return records for this species have been
recorded in which.the length of time between date of capture
records is greater than one year; and (2), an indication of

a flocking tendency is Shown.

NEGRATION PEAKS 44

Considerable time has been.devoted to the study Of mi-
gration curves for Slate-colored Juncos at Mighigan State Col-
lege. These birds attracted early attention at the banding
station because of their arrival in large numbers and because
of their unusual spring and fall migration habits. The rec-
ords of bandings cover the years 1924 to 1939 for both spring
and fall, and form.the basis for a study of migration peaks
as well as the duration of the migrating seasons.

Graphs V to XV'show the curves of Spring migration for
ten years, charted by three-day periods, While the larger num-
ber of the graphs Show a clearly defined migration peak, it
should be noted that some of them.illustrate the fact that
migration was already in.progress at the time the collection
of data was begun. From these latter graphs it would be dif-
ficult to determine Whether or not the peak of migration was
reached before or after'the beginning Of trapping operations.
For some of the years, 1924, 1925, 1926, 1927, and 1931, the
number of birds banded was small, definite curves were not
shown, and.therefore graphs are not included.

Graphs for 1928, 1929, 1930, 1938 and 1939 are those for
the years in.which spring migration was already in progress
at the time the collection of data was begun. It is probable,
therefore, that the peak of migration.may have Occurred be-
fore the traps were opened, or at least was occurring during
the period in which.they'were opened. During the years 1932,
1933, 1934, 1935, 1936 and 1937 definite peaks appear some

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49
time after'the opening dates. These peak dates range from

the earliest, April 10 to 12, in 1932 and l934, to the latest,
April 25 to 27 in 1936. The only period inuwhich two peaks
occur is April 10 to 12. Graph XVIII Shows the average per-
cent of the total number banded fox'these years in.which a
definite peak is Shown after*the traps were opened, i.e.,
1932, l933, 1934, 1935, 1936 and 1937. It may be seen from
this curve that for these years, the only ones for which come
plate data is available, the average peak is April 10 to 12.

Graph.XVI is a comprehensive graph of all data available
on Slate-colored Juncos banded during spring migrations.
This includes not only the data collected in regular studies
at the College Banding Station but also considerable informa-
tion collected by students engaged in special studies during
winter and spring terms at times when.the regular traps were
not open.

The maximum period of fall migration was most frequent-
ly found to be from.October 16 to 18. The peak was October
'7 to 9 during the years of 1924, 1929, and 1930. For the
two years 1927 and 1928 the period of maximum movement oc-
curred from.October l0 to 12. In the five years 1926, 1932,
1935, 1936, and 1939 (33% of the total years) the pinnacle
came from.October 16 to 18. The peak for 1955 was reached
between October 19 and October 21. In the fall of 1937 the
period of greatest intensity was from.October 22 to 24; and
the peaks in 1925 and 1934 fell from.October 28 to 50.

The number of birds banded throughout the first three-

day period is rarely more than two or three. This indicates

50
that the onset of fall migration is closely correlated with

the beginning of handing operations in.the fall term. 'We

are therefore fortunate in having almost complete fall mi-

gration records for this species.

Graphs XVI and XVII, together, present the spring and
fall migration curves for'Slate-colored Juncos. Each point
on these curves is the average number ofbirds banded on
three successive days over a period of sixteen years. These
curves may be used in.the future as standards for comparison
with curves for individual years. It must be borne in mind
however that these are average curves constructed from.re-
cords over a.period of sixteen years and curves for indivi-
dual years may vary considerably.

Inspection of these curves leads to the following gen-
eral conclusions concerning the spring and fall migrations
for Slate-colored Juncos:

l. The fall migration lasts longer than the spring.

This difference is primarily due to a more leisurely

passage in fall than in spring.

2. The period of maximum intensity is much longer in
the fall than in.the spring. The peak of maximum
intensity is higher, however, in.the spring than
in the fall.

3. Some birds spend their entire winters in.this area.
This is indicated by the fact that some birds are
captured as long as the traps are operated in.the
fall and is further supported by records of stu-

dents conducting special banding studies in the win-

5.

51
ter term.

There is a greater tendency to show a definite peak
in the spring than in the fall. This sharp rise to

a peak is characteristic of spring migrations in
general, but here it is partially due to the lateness
in opening the traps in the spring.

The curves are very irregular. This is probably due
to the relatively irregular migratory habits of this

Species.

 

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54
COMPARISON OF MIGRATION RECORDS

l. A significantly greater number of White-throated
Sparrows are banded in the spring than in the fall. This
difference would be due to chance once in twenty times.

2. A greater number of Slate-colored Juncos are
banded during the fall than during the spring. A differ-
ence as great as the one found.would occur due to chance
once in five times.

5. A significantly greater percent of repeats for Wh-
ite-throated Sparrows occurs in fall than in.spring. This
difference would be due to chance considerably less than once
in one hundred times.

4. There is a greater percent of repeats for Slate-
colored Juncos in the fall than in the Spring. The differ-
ence would occur due to chance once in three times.

5. StOp-over periods are significantly longer for White—
throated Sparrows in the fall than in the spring. The dif-
ference would be due to chance once in one hundred times.

6. Stop-over periods for Slate-colored Juncos are sig-
nificantly longer in fall than in.spring. The difference
would be due to chance once in twenty times.

. 7. The difference in the length of time between repeats
in spring and fall is insignificant for both'White-throated
Sparrows and Slate-colored Juncos.

8. For Slate-colored Juncos the tendency to form.the
trap habit is equally great in fall and spring.

9. The average peak of spring migration for White-th-
roated Sparrows falls between may 7 and May 9.

55
10. The average peak of fall migrations for White-

throated Sparrows was from October 1 to 3.

11. The period of greatest banding activity for Slate-
colored Juncos during the spring is April 10 to 12.

12. The average fall migration.curve for Slate-colored
Juncos does not Show a definite three-day peak. Over a perb
iod of sixteen years maximum.numbers have been banded main-
ly during the periods of October 16 to l8, 17 to 19, 20 to
22, and 28 to 30. This is due to a more leisurely migration
in the fall than in the spring.

13. The average spring migratory period for‘White-throat-
ed Sparrows is April 23 14 days, to May 19 $4.5 days, or a
period of 27 $8.5 days.

14. It was impossible to determine average first cap-
ture dates-in the fall for White-throated Sparrows since mi-
gration usually begins before traps are opened. The average
date of last capture in the fall for this species was found
to be between October 27 and 28;;7 days. First banding re-
cords at this station range from.September 16 to 30. USing
September 23 as a median date, fall migration lasts a.mini-
mum of 35 days.

15. It was impossible to determine exact beginning
dates for spring migrations or closing dates of correspond-
ing fall periods for Slate-colored Juneos. Nhgration usual-
ly begins in the spring before traps are opened. The mini-
mum date for first records at this station is approximately
April 9. The average date for last records in the spring is
approximately April 30. The minimum.spring period is there-

56
fore 21 days.

6. The termination.of fall migration is not well de-
fined for Slate-colored Juncos since a few are taken as long
as traps are open in.the winter. These birds evidently win-
ter in this region. Migration begins at about October 1 and
appears to be over at approximately November 20. Thus the
period of fall migration is about 50 days.

17. In general fall migration covers a greater period
of days and is less regular than the corresponding spring
period. This is true for both Slate-colored Juncos and

'White-throated Sparrows.

57
STUDY OF BAIT PREFERENCES

Method 9; Procedure

A bait study eXperiment was set up in 1927 and 1928
under Professor Stack's guidance and conducted by L.C.
Stegeman, now affiliated with the Roosevelt Wildlife Experi-
ment Station at Syracuse, new York. The object of this ex-
periment was to study the food habits of birds caught with
relation to habitat.

Two batteries of eight traps each were placed in differ-
ent habitats. Habitat I was located in an Open field about
midsway along, and adjacent to, the south side of a fence en-
closing a beech-maple woodlot, known as College River'Wood-
lot. Habitat II was placed on the south side of a clump of
shrubs in an otherwise open field just south of the afore-
mentioned woodlot. The two habitats were approximately nin-
ty feet apart. Traps were placed side by side, six feet from
one another in each habitat and the traps of each battery
were placed to face in the same direction. Each trap*was sup-
plied with a different bait, although the same ones were used
in both batteries. The baits were millet, Wheat, hemp,
cracked corn, buckwheat, sunflower seed, and suet. The traps
of both habitats were operated.for the same period of time,
from September 26, 1927 to April 17, 1928. The birds caught,
therefore, were mainly fall migrants and winter residents,

with a few early spring migrants.

58
Statement 2§_Resu1ts

In Habitat I 181 birds, representing 13 species, were
caught a total of 563 times. In Habitat II 224 birds, 16
species, were captured 505 times. The average number of
catches per individual in Habitat I was 3.11 and.the aver-
age in Habitat II was 2.25. This difference was not consider-
ed to be significant but probably was due to chance. The
samples were too small for statistical comparison.

Species caught in.Eabitat II and not in.Habitat I were
the Olive—backed Thrush, Brown Thrasher, Hermit Thrush, and
jMourning Dove. All species with the exception of Downy Wood-
peckers were caught in Habitat II. A

The following were caught in both habitats: 2 (7%) Tree
Sparrows, 4 (21%) Towhees, 8 (40%) Juncos, 2 (28%) Nuthatches,
2 (40%) Tufted Titmice, 2 (28%) Cardinals, and l (33%) Blue
Jays.

It is interesting to note that of 32‘White-throated Spar-
rows that were caught 87 times, not a single individual was
caught in both habitats. This suggests that even though large
numbers of this species may be in a locality, the number of
catches may be very small. It has been noticed that during
the earlier part of a White-throated Sparrow's migration per-
iod, sight records may be numerous and still catches be very
infrequent, even though the traps are located in an area.where
later they are seen and caught in large numbers. These evi-
dences seem to indicate that movements during.migrations in

search of food are limited to small areas and that stop-overs

59

are more for short periods of rest.

It was found that the variations which occurred in the

number of catches with different baits could not have arisen

due to chance alone. In other words definite preferences

are shown for certain baits. The following preferences were

determined:

1.

2.

3.

4.

8..

a.

8..

b.

(Tables XIII to XXIII)

In Habitat I Song Sparrows showed a signi-
ficant preference for millet over the bait
with the second most catches, buckwheat.

In Habitat II Song Sparrows did not show a
Significant preference between any of the
baits.

In Habitat I Juncos showed a significant
preference for millet over-the bait with the
second most catches, hemp.

In Habitat II Juncos did not Show a signi-
ficant preference.

In Habitat I and Habitat II Chickadees show-
ed a significant preference for sunflower
seed over the bait with the second most catch-
es, suet.

In Habitat I Tree Sparrows showed a signi-
ficant preference for millet over the bait
with the second most catches, hemp.

In Habitat II Tree Sparrows showed a signi-
ficant preference for:millet over the bait

with the second most catches, corn.

6O
5. Ianabitat I Quail did not show a signifi-

cant preferemce at the five percent level.
In other words, the difference between first
and second choices would be due to chance
once in twenty times. At the sevenpercent
level however they did show a significant
preference for hemp over the bait with the
second.most catches, wheat. In Habitat II
the number of catches was not large enough
to make a statistical analysis.

6. In both habitats Towhees did net'show a signi-

preference.

It is somewhat difficult to understand why any species
would show a preference for a particular bait in one habitat
and not in the other. It seems improbable that the two habi-
tats were dissimilar enough to produce this result even tho-
ugh the difference was shown to be significant statistically.
‘What is probably more important is the preferences for bait
shown in Tables XXIV'and.XXV. These show a significant liking
on the part of the six species caught in largest numbers in
both habitats for.millet, with hemp as their second choice.

One of the most interesting things shown by this study is
the preference for suet and sunflower seed by the Chickadee, a
bird that is caught mainly during the winter months as con-
trasted with.the other birds which are caught mainly during
the warmer periods of the year. This would indicate a heed

for a heat producing diet. The correlation of a preference

with the need has, to the knowledge of the author, never been

61
proven. The possibility of using this approach to the solu-

tion of problems concerning physiological needs might well be
further investigated.

SPECIES

 

62

IMIBERS OF CATCESS CHARTED BY SPECIES AND BAITS

Tufted Titmouse

Table XI, (Habitat I)

C M __I_i__ B W __S_]§: S A TOTAL 110 .BIRDS
"‘17“' "1"22‘ 4 "5"‘5‘ 2 "'5"‘6‘ "75:‘ “Tfi7“"
2 10 92 56 22 2 6 10 4 202 66
3 l l 6 1 0 22 10 0 41 15
4 3 53 0 15 6 2 l 0 80 30
5 9 44 14 3 l 6 1 l 70 16
6 2 2 l9 6 9 0 0 0 38 9
7 11 O l 13 2 3 2 l 33 13
8 l O 2 0 0 12 14 0 29 5
9 0 0 2 O 0 6 3 f 0 ll 5
10 0 3 l 2 l 0 O 0 7 6
ll 0 O 0 0 0 l 0 0 l 1
l2 0 0 2 l 0 l l l 6 3
l3 0 0 0 O O _J_:_ l O 2 2
35‘2I7‘IU7“€§'221‘ 62 ZET"IV' 'Efifir' '1EfiT""
Table XII, (Habitat II)
SPECIES C M H B W SF S __A_ TOTAL NO . BIRDS
I ' I5“ I?“ IZ‘ If "3- 8 T 2 '74 21
2 34 47 38 38 2O 9 2 3 192 112
3 2 l l l l 37 4 0 4'7 13
4 O 3 2 O l O 1 0 '7 2
5 15 48 12 7 5 6 l 0 94 22
6 l 2 ll 2 2 1 l 0 2O 10
'7 l3 0 5 4 3 O 0 0 25 10
8 2 0 2 0 0 2 l 0 7 4
9 0 0 0 0 0 2 3 0 5 2
10 O 0 4 0 0 0 0 0 4 4
ll 1 0 O O 2 3 0 0 6 3
l2 1 l 4 0 0 l 0 O 7 6
l3 1 0 0 l 0 O 0 0 2 2
l4 0 O O 0 O 0 l l 2 2
15 l l 0 0 0 6 O l 9 8
l6 0 0 l O 3 O 0 0 4 3
W120“ 574" 6'2— 2:6" '75" 1'5" '7" 505' 224
LEGEND
SPECIES BAITS
I. Song Sparrow 10. Fox Sparrow C. Corn
2. Junco 11. Blue Jay H. Hemp
3. Chickadee 12. Cardinal M. Millet
4. White-throated Sparrow 13. Downy Woodpecker B. Buckwheat
5. Tree Sparrow l4. Olive-Backed ThrushS. Suet
6. Quail 15. Brown Thrasher A. Apple
7. Towhee 16. Hermit Thrush SF. Sunflow-
8. White-breasted Nuthatchl'Z. Mourning Dove er seed

63
TESTS FOR SIGNIFICANCE BETWEEN FIRST AND SECOND

MOST POPULAR BAITS BY SPECIES

Table XIII, Song Sparrow Table XIV, Song Sparrow
(Habitat I) (Habitat II)
LI B M? 0
Observed 22 5 Observed 17 15
Expected 13.5 13.5 Expected l6 16
Deviation 7.5 7.5 Deviagion 1 l
x 8.34 x 0.12
Table XX, Slate Colored Jun-Table XVI, Slate-Colored Jun-
(Habitat I) co (Habitat II) co
MI H MI B
Observed 92 56 Observed .47 38
Expected 74 74 Expected 42.5 42.5
Deviatéon 18 18 Deviation 4.5 4.5
x 8.8 x2 0.94
Table XVII, Chickadee Table XVIII,Chickadee
(Habitat I) (Habitat II)
SE S SF S
Observed 22 10 Observed 37 4
Expected 16 16 Expected 20.5 20.5
Deviatgon 6 6 Deviagion 16.5 16.5
x 4.5 x 26.4
Table XIX, Tree Sparrow Table XX, Tree Sparrow
(Habitat I) (Habitat II)
MI HI Ml C
Observed 44 14 Observed 48 15
Expected 29 29 Expected 31.5 31.5
Deviatfion 15 15 Deviagion 16.5 16.5
x 15.4 x 17.2
Table XXI, Quail Insufficient number of
(Habitat I) Quail caught in Habitat
A H W Two for statistical
Observed 19.9 9 analysis.
Expected 14 14
Deviatgon 5 5
x 3.6
Table XXII, Towhee Table XXIII,Towhee
(Habitat I) (Habitat II)
.B C H .C
Observed 5 13 Observed 13 11
Expected 9 9 Expected 12 12
Deviatéon 4 4 DeviaEion 1 l
x 3.54 x 0.16

Legend: Baits, H, hemp; M;.millet; C, corn;'W, wheat;
B2 buckwheat; SF, sunflower seed; S, suet.
x , Chi Square.5

64
TESTS FOR SIGNIFICAHCE BETWEEN FIRST AND SECOND

MOST POPULAR BAITS FOR SIX SPECIES

Table XXIV, All Six Species Table XXV, All Six Species

(fiabi tat é) (Hafiitat ILA
Observed 214 100 Observed 118 83
Expected 157 157 Expected 100.5 100.5
Deviation 57 57 Deviation 17.5 17.5
x2 41.4 x3 6.1

Legend: Baits, H, hemp; M, millet; C, corn; W, wheat;
B buckwheat; SF, sunflower seed; S, suet.
xé, Chi Square.5

l.

4.

5.

65

BIBLIOGRAPHY

Baten, W. D. mathematical Statistics. John.Wiley
& Sons, Inc., New York, N.Y. 1938.

Lincoln, F. C. United States Bureau of Agriculture.
Circular 363. 1935.

Rowan,‘WilliamJ The Riddle of Migration.
The Williams & Wilkins Company, Baltimore. 1931.

Baldwin, S. Prentiss. Bird Banding By Means
of Systematic Trapping. From.abstract of pro-
ceedings, Linnean Society of New York. 1919.

Snedecor, G. W. Statistical methods.- Collegiate
Press, Inc., Ames Iowa. 1937.

Idncoln, F.C. The Migration.of American Birds.

’ Doubleday, Doran a Company, Inc., 1959.

Bradt, G. W. Some Studies in Bird Banding.
Thesis for Degree of Master of Science at

NHchigan State College. 1926.

 

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