No abstract

Seasonal adjustments and individual responses to environmental perturbations have been well characterized in many passerine species but similar studies in other groups of birds are sparse. Larger-bodied and longer-lived avian species have different life-history strategies and different energy-storage and -utilization patterns. We investigated the response to capture stress in male and female Harlequin Ducks (Histrionicus histrionicus) during the breeding season on montane rivers and during moult on coastal waterways of Washington State. Females arrived at the breeding grounds in better condition and had a smaller rise in circulating corticosterone during 1 h of restraint than males. As the breeding season progressed, body condition declined in females and their adrenocortical response to acute stress became more pronounced. A potentially disruptive environmental condition, high river flow during the breeding season, was not associated with lower nesting success, lower body condition indices, or higher corticosterone levels (baseline or maximum concentration). The maximum corticosterone concentration reached over 1 h of restraint was negatively correlated with body condition in females during the breeding season. Lastly, males and females had similar adrenocortical responses to capture and handling during moult. We relate differential responses to acute stress between males and females to different selective pressures during the breeding season.

We determined survival rates, causes of mortality, and documented impacts of harvest on ≥1.5‐year‐old male (hereafter, male) Columbian black‐tailed deer (Odocoileus hemionus columbianus) in 2 Washington, USA, game management units (GMUs; Skookumchuck and Snoqualmie) characterized by different hunting‐season structures. We monitored 66 males (n = 28 and 38 annually) in Skookumchuck and 58 males (n = 26 and 32 annually) in Snoqualmie, September 1999‐September 2001. Annual survival rates were 0.498 (SE = 0.066) in Skookumchuck and 0.519 (SE = 0.067) in Snoqualmie. Survival rates derived from population age structure did not differ from rates derived from radiotelemetry. Harvest was the primary mortality factor for each population, accounting for 67% (SE = 7; Skookumchuck) to 44% (SE = 9; Snoqualmie) of total annual mortality. Annual harvest‐specific mortality rates were 0.317 (SE = 0.032) in Skookumchuck and 0.211 (SE = 0.021) in Snoqualmie, likely due to longer hunting seasons and greater hunter effort in Skookumchuck. Following the elimination of a late buck season centered on the rut in Snoqualmie, male harvest declined 56% and annual survival increased 60%, indicating that male harvest was largely additive to other mortality. Our results indicated that harvest was the primary influence on male black‐tailed deer populations in Washington, was additive, and that the effect of harvest varied with hunting‐season structure and hunter effort. Managers should not assume that harvesting removes a constant proportion of the male population annually, and management models that assume compensatory mortality in adult harvest may result in over‐harvest of male populations.

Many shorebirds exhibit within-and among-year site fidelity during their annual cycle. Little is known, however, about the migration ecology of Red Knots (Calidris canutus) that migrate along the Pacific Flyway and occur in Washington in numbers that exceed counts elsewhere on the flyway. At two large estuaries in coastal Washington, Grays Harbor and Willapa Bay, we searched for and recorded the locations of Red Knots (N = 547) that had been individually marked with leg flags at their wintering grounds in Baja California Sur, Mexico, during the period from October 2006 to April 2009. In 2010, we resighted 43 Red Knots at Grays Harbor and Willapa Bay that had been observed at these sites in previous years, primarily in 2009. We found a high degree of site fidelity between years, with birds observed in 2010 more likely to return to the same stopover site used in 2009 than to switch stopover sites. For knots that did not switch estuaries between years, the median nearest distance between locations where individuals were observed between years was 1.4 km at Grays Harbor and 0.6 km at Willapa Bay. Our results provide the first evidence of stopover site fidelity by Red Knots of the roselaari subspecies. Fidelity occurred at three spatial scales: coastal Washington, the two estuaries where we conducted our study, and specific mudflat areas within the estuaries. Because our study sites support high populations of bivalves, Red Knots may be returning to the same areas in subsequent years to exploit what we suspect is a predictable food resource. The abundance of Red Knots and high degree of site fidelity suggest that our study sites in Grays Harbor and Willapa Bay are important for the conservation of this species on the Pacific Flyway. RESUMEN. Fidelidad interanual del Playero rojizo al sitio de escala migratoria más importante del Corredor del PacíficoNo hay información sobre la fidelidad de los playeros rojizos del Pacífico (Calidris canutus roselaari) a las costas de Washington, pese a que en ellas sus números superan los de otras partes de la ruta migratoria. Investigaciones de fidelidad al sitio permitirán contextualizar la importancia de los estuarios de Washington para esta subespecie en su migración al norte. En las primaveras de 2009 y 2010 registramos, en Grays Harbor y Bahía Willapa, playeros rojizos marcados individualmente con banderas en las patas (N = 547). Las aves se marcaron en Baja California Sur, México, su principal zona de invernación, entre octubre de 2006 y abril de 2009. En 2010 observamos 43 playeros rojizos previamente registrados, sobre todo en 2009. Encontramos una fidelidad interanual alta al sitio, con mayor probabilidad de reobservar a las aves en el mismo sitio en ambos años. Además la distancia entre las localidades donde registramos a los individuos en los dos años, sugiere una fidelidad alta a zonas específicas dentro de los sitios de escala. La distancia media entre las localidades de observación (diferentes años), fue de 1.4 km para Grays Harbor y 0.6 km para Bahía Willapa. Nuestros ...

No abstract