Survival of Breeding Pacific Common Eiders on the Yukon-Kuskokwim Delta,Alaska |
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Authors: | HEATHER M. WILSON PAUL L. FLINT CHRISTINE L. MORAN ABBY N. POWELL |
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Affiliation: | 1. United States Geological Survey, Alaska Science Center, 1011 E. Tudor Road, Anchorage, AK 99503, USA;2. United States Fish and Wildlife Service, Yukon Delta National Wildlife Refuge, P.O. Box 346, Bethel, AK 99559, USA Selawik National Wildlife Refuge, P.O. Box 270, Kotzebue, AK 99752, USA;3. United States Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, and Institute of Arctic Biology, University of Alaska, Fairbanks, 209 Irving I, Fairbanks, AK 99775, USA |
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Abstract: | ABSTRACT Populations of Pacific common eiders (Somateria mollissima v-nigrum) breeding in Alaska, USA, have declined markedly over the past 40 years. We studied survival of adult female Pacific common eiders using capture—recapture of nesting hens at 3 sites on the Yukon-Kuskokwim Delta (YKD), Alaska from 1994 to 2004. We used data consisting of 268 recapture events from 361 uniquely marked individuals to investigate temporal, geographic, and environmental variation in adult female survival. Our results suggest apparent annual survival of adult eiders from the YKD was high (0.892, SE = 0.022) and spatially and temporally invariant (σ2 = 0.005), a pattern consistent with other long-lived marine birds. Moreover, our results suggest adult survival may be functionally fixed for Pacific common eiders, and at the present, adult survival may be relatively unresponsive to environmental or management perturbations. Our data did not support hypothesized variation in survival relative to mortality factors such as predation on breeding grounds, physiologic costs of reproduction, and wintering conditions. Although changes in adult survival likely have a large potential effect on prospective population growth, our results suggest viable management actions aimed at increasing survival may be extremely limited. |
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Keywords: | adult female apparent survival Alaska mark-recapture Pacific common eider Somateria mollissima v-nigrum Yukon-Kuskokwim Delta |
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