Role of wetlands and endogenous factors on incubation behavior of nesting spectacled eiders on the Yukon-Kuskokwim Delta, Alaska

Abstract

Patterns of nest attendance in ducks vary with endogenous and environmental factors. We examined variation in nest attendance of spectacled eiders on the Yukon-Kuskokwim Delta, Alaska, during 1997-1998. We also examined spatial and temporal variation in wetland characteristics and potential foods available to nesting spectacled eiders. Time spent foraging was greater when spectacled eiders traveled farther to feed, and nest attendance was lower when food was more abundant, suggesting that females made tradeoffs between foraging and energetic requirements of nesting in response to food abundance and wetland conditions. Wetlands were dynamic, and food abundance varied with pond depth and total dissolved solids. Spectacled eiders responded in complex ways to a suite of physiological and environmental variables, and employed an overall behavioral strategy that optimized foraging behavior in response to food abundance, while minimizing risk of depleting nutrient reserves sufficiently to force nest abandonment or increase the risk of female mortality.