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1 December 2008 Apparent Survival of Male Harlequin Ducks Molting at the Gannet Islands, Labrador
Peter W. Thomas, Gregory J. Robertson
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Survival rates are an essential parameter for understanding the dynamics and status of wild populations. Apparent survival (the combined probability of surviving and returning to a site) and capture rates were estimated for male Harlequin Ducks (Histrionicus histrionicus) (second-year, N = 30, adult, N = 83) that were captured and/or resighted on the Gannet Islands, Labrador, from 1999-2003. Most birds available for analysis were first captured locally (N = 74), although a significant number were originally banded on wintering grounds in Maine (N = 36), and the remaining three were banded on breeding grounds. Second-year male apparent survival rates were low (0.466 ± 0.118; 95% PLI: 0.256 - 0.689), and different from adult rates (0.744 ± 0.045; 0.647 - 0.822), likely due to increased dispersal of young birds. There was little evidence for annual variation in survival rates, but samples sizes were low. Apparent survival rates of male Harlequin Ducks were lower than found in most studies, suggesting that some males emigrate from the Gannet Islands molting site, but do confirm that there is some fidelity to molting sites, similar to observations of the Pacific population.

Peter W. Thomas and Gregory J. Robertson "Apparent Survival of Male Harlequin Ducks Molting at the Gannet Islands, Labrador," Waterbirds 31(sp2), 147-151, (1 December 2008).
Published: 1 December 2008

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