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Population status of Common Guillemots Uria aalge at a colony in western Alaska: results and simulations
Author(s) -
MURPHY EDWARD C.,
SPRINGER ALAN M.,
ROSENEAU DAVID G.
Publication year - 1986
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1986.tb02685.x
Subject(s) - uria aalge , biology , population , zoology , demography , geography , ecology , seabird , predation , sociology
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.