Population status of Common Guillemots Uria aalge at a colony in western Alaska: results and simulations |
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| Authors: | EDWARD C. MURPHY,ALAN M. SPRINGER&dagger ,DAVID G. ROSENEAU&Dagger |
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| Affiliation: | *Institute of Arctic Biology and Department of Biology, Fisheries and Wildlife, Alaska 99775;†Institute of Marine Science, University of Alaska, Fairbanks, Alaska 99775;‡LGL Alaska Research Associates, Inc., P.O. Box 80607, Fairbanks, Alaska 99708. |
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| Abstract: | Colony-wide boat-based censuses suggest that numbers of Common Guillemots at Bluff, Alaska declined markedly in the late 1970s and remained low until 1983. Annual land-based counts of study plots since 1979 generally showed no trend. However, numbers declined substantially in one study area between 1978 and 1983. Reproductive success varied considerably among years and was highest in moderately warm summers. Simulation analyses suggest that the changes in numbers cannot be attributed to changes in reproductive success several years previously. Thus, factors affecting survival, presumably in winter, are apparently implicated in the declines. |
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