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Demography of Swainson's Hawks Breeding in Western Canada
Author(s) -
SCHMUTZ JOSEF K.,
MCLOUGHLIN PHILIP D.,
HOUSTON C. STUART
Publication year - 2006
Publication title -
the journal of wildlife management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.94
H-Index - 111
eISSN - 1937-2817
pISSN - 0022-541X
DOI - 10.2193/0022-541x(2006)70[1455:doshbi]2.0.co;2
Subject(s) - buteo , population , predation , reproduction , demography , geography , vital rates , mortality rate , population size , fishery , biology , ecology , population growth , sociology
Our objective was to estimate demographic parameters and population trends for Swainson's hawks (Buteo swainsoni) breeding in southeast Alberta and southwest Saskatchewan, Canada, from 1972 to 2003. We assembled mark‐resighting‐recovery histories of 6,606 banded Swainson's hawks for a joint analysis of survival and resighting probability, including band‐reporting rate and fidelity of animals, following Burnham's joint resighting‐recovery model provided in program MARK. Our best‐fitting survival model specified age‐related variation in survival, resighting probability, and fidelity, and it specified age‐by‐temporal variation in nestling survival and adult resighting probability. From estimated survival rates and previously published data on reproduction, for the period 1973–1996 we estimated the population's finite rate of increase, λ, to be 0.996 (95% CI: 0.945–1.057). We believe that population limitation of Swainson's hawks is primarily related to the influence of prey availability on brood size and nestling survival. Despite indications of recent population declines, we conclude that Swainson's hawks breeding in western Canada are not currently in need of special management action.