Variation in Breeding Season Survival of Female Harlequin Ducks

Abstract

Quantifying sources of variation in demographic rates can provide insight into processes underlying population dynamics and subsequently direct wildlife conservation. In the context of avian life history, understanding patterns of variation in survival rates of breeding females is particularly relevant because this cohort often has a disproportionately large effect on population dynamics. We estimated survival probability for 144 adult female harlequin ducks (Histrionicus histrionicus) that we marked with radiotransmitters and tracked at 4 breeding areas in western North America. Model selection results indicated both regional and temporal variation in survival rates, with most mortality attributed to predation. Cumulative survival probability (6SE) during the 100-day study period was lower at 2 sites in the Rocky Mountains of Alberta, Canada (AB1 and AB2: 0.75 6 0.11) than in the Coast Mountains of British Columbia, Canada (BC: 0.88 6 0.08) or the Cascade Mountains of Oregon, USA (OR: 0.89 6 0.08). Survival also was lower during incubation than nest-initiation or brood-rearing stages at all 4 study areas. In comparison to other annual cycle stages and locations, harlequin duck mortality rates were highest on the breeding grounds, suggesting that management actions designed to reduce mortality during breeding would achieve meaningful population-level benefits. Bond et al. N Harlequin Duck Survival 965

Annual survival in female white‐winged scoters and lesser scaup

“…However, these values differed markedly from those of Martin et al () who attributed higher survival of female scaup in Alaska to low breeding propensity, and Koons and Rotella (), who implied that lower female survival of parkland scaup may have been due to high mink ( Neovison vison ) predation during a longer nesting season than typically encountered in the far north. Across multiple studies, between 23% and 63% of annual female scaup mortality occurred during the breeding season (Table ), most of which likely occurred during nesting when females are more susceptible to predation (Koons and Rotella , Bond et al ). Thus, these results reinforce the importance of breeding season events on population dynamics in scaup (Koons et al , ).…”

Female Harlequin Duck Winter Survival 11 to 14 Years After the Exxon Valdez Oil Spill

“…We also demonstrate that, after accounting for seasonal variation that affected all age classes, winter survival of HY females was consistently lower than that of AHY females, which also was described by Mittelhauser (2008). Similar annual survival rates of female harlequin ducks of both age classes (Cooke et al 2000) may reflect a balance between higher mortality of young females during winter and mortality incurred by adult females on breeding streams (Mittelhauser 2008, Bond et al 2009). Our findings contribute to a body of literature describing harlequin duck survival throughout the annual cycle, which will be important for understanding when and where demographic constraints on population growth are manifested (Cooke et al 2000, Iverson and Esler 2007, Mittlehauser 2008, Bond et al 2009).…”

The effects of a large‐scale wind farm on breeding season survival of female mallards and blue‐winged teal in the Prairie Pothole Region

“…An unbiased test and associated adjustment factor for correlation of fates and heterogeneity of survival is not available for nest survival models in Program MARK (Dinsmore et al , Rotella et al ). Nevertheless, little evidence exists for correlation and heterogeneity of fates in large samples of radio‐marked mallards, and previous researchers have used unadjusted estimates and model selection criteria for inference in studies of survival of radio‐marked females (Devries et al , Brasher et al , Bond et al ). We adopted this approach to the analysis of our smaller dataset.…”