Variation in Emperor Goose (Anser canagicus) Body Mass at the Geographic Extremes of their Wintering Range
Category: Research Poster
Author(s): Sophie Scholl
Presenter(s): Sophie Scholl
Mentors(s): Robyn Thomas, Lise Aubry
The emperor goose (Anser canagicus) is a waterfowl species with unique wintering ecology as they migrate only slightly south of their summer breeding grounds in the Yukon-Kuskokwim Delta to non-breeding wintering grounds at relatively high latitudes along the Aleutian Islands and the Kodiak Archipelago. Recent declines in emperor goose populations highlight the importance of developing a more comprehensive understanding of emperor goose wintering ecology. This study explores differences of body mass as a proxy for individual fitness between two wintering sites that represent the geographic extremes of the emperor goose wintering distribution: Shemya Island and the Kodiak Archipelago. Amongst all adult geese, specifically adult females, the geese on Shemya had significantly lower body mass than those on Kodiak. Additionally, variation in body mass among emperor geese could be explained by additive effects of age class, sex, and field site. These findings indicate that differences in environmental conditions, food source availability, and migration distance to the different wintering sites between Shemya and Kodiak could explain why some demographic groups of emperor geese displayed lower body masses, and therefore lower fitness, at Shemya. Dedicating more resources to explaining variability in fitness experienced by emperor geese at their wintering sites is critical for understanding the best conservation and management strategies to prevent further population declines.