Mute swans (Cygnus olor) were introduced by humans to Michigan with translocation of one pair from Iowa into Michigan’s Charlevoix County in 1919. Michigan’s mute swan population peaked in 2013 with an estimated abundance of 17,520 individuals. This coincided with the Michigan Department of Natural Resources drafting a policy which sought fewer than 2,000 wild mute swans present in Michigan by 2030. However, uncertainty in life stage-specific demographic rates and movements did not allow for robust analyses of levels and types of management needed to achieve the long-term goal. A pilot project was launched in 2014 to investigate inter- and intrastate movements of mute swans within the Great Lakes region. This effort spawned a formal research partnership between Michigan State University, the Michigan Department of Natural Resources, and the Wildlife Services division of the U.S. Department of Agriculture Animal and Plant Health Inspection Service. The goals of this research were to refine mute swan management strategies in Michigan by incorporating region-specific parameters into demographic models and to understand seasonal movements of mute swans. We investigated nesting ecology and life stage-specific survival and movements for mute swans located in the Lower Peninsula of Michigan. We used aerial surveys to locate nests and fledged young within site boundaries. We used boats to neck collar individuals and visit nests. Estimated nest survival (Ŝ = 0.701), mean egg volume (328.2 ± SD 26.6 cm3), and mean incubation initiation date (8 April) were comparable to estimates from other portions of mute swan range. Mean clutch size (7.0 ± SE 0.15) was slightly higher than in areas of their native range, but comparable to estimates from the introduced range in North America. Apparent cygnet survival (i.e., hatch to estimated fledge; 0.27 ± 0.01), brood survival (0.58 ± 0.03), overall productivity (1.2 fledglings/pair), and percentage of gray young in newly hatched broods (36.9% gray plumage) were slightly lower compared to portions of native range. Observed breeding productivity related to saturation of characteristic nesting habitat (^ = -0.9792, p = 0.04). Seven-month survival estimates for fledged young (Ŝ = 0.526, 95% CI = 0.342 – 0.703) were slightly lower than areas of their native range and may be related to ratio of gray and leucistic morph individuals in our population (^leucistic = -0.908, 95% CI = -2.086 – 0.269). Estimated annual survival for non-breeding (Ŝ = 0.698, 95% CI = 0.419 – 0.881) and breeding swans (Ŝ = 0.850, 95% CI = 0.686 – 0.936) was slightly less but near reported values for native range. Breeding female mute swans remained on or close to nesting territories year-round and were furthest from territories during winter (x̄ = 11.3 km). Juvenile-marked female swans tended to move farther from natal areas than juvenile-marked males during their first 2 years of life; however, juvenile-marked females were closer to natal territories than juvenile-marked males at the end of the study.We parameterized a density-dependent matrix population model for Michigan using estimated values from this research. This model suggests that survival rates for juvenile, non-breeding, and breeding swans should be reduced by 26% annually to achieve the long-term goal of fewer than 2,000 mute swans statewide by 2030. This requires a 17% removal of the annual population to reach the long-term goal (12,760 swans removed 2018 – 2029). Importantly, removals must be spread evenly across all life stages. Targeting removal across all adult population segments is the most efficient control strategy, as 94% of mute swan nests would need to be destroyed annually (15,748 nests destroyed 2018 – 2029) to achieve the same goal.
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