Food habits and levels of organochlorine compounds, lead, and mercury in resident and wintering bald eagles were studied in southcentral Oregon and California, 1979-83. Food habits were assessed by examination of castings from winter communal roosts, identification of 2938 prey items found at nest sites and foraging areas, and observations...
Populations of organisms are influenced by both top-down (predator driven) and bottom-up (environment or resource driven) effects. Seabird research has largely focused on bottom-up factors influencing reproduction, with little emphasis on top-down. Our goal was to better understand top-down impacts on colonial nesting seabirds over a range of spatio-temporal scales....
To assess the consequences of increased recreational activity on bald eagles (Haliaeetus leucocephalus), we studied factors that influenced their behavior and reproductive success in the Gulkana River basin, Alaska, from 1989 to 1993. Both extrinsic and intrinsic factors were associated with reproductive success. Productivity averaged 0.86 young fledged per occupied...
