The diet of Bald Eagles, Haliaeetus leucocephalus, wintering in the lower Great Lakes basin. 1987-1995

Abstract

Observations of wintering Bald Eagles (Haliaeetus leucocephalus) from the lower Great Lakes basin feeding on identifiable food items provide an indication of winter diet for this population.Overall, 47% of 339 feeding observations were on carcasses of White-tailed Deer ((Odocoileus virginianus), 23% on fish, 11% on other mammal species, 10% on offal and human garbage, and 9% on birds.Only 35% of food items were of aquatic origin.Diet composition varied significantly by region, and eagle age.Garbage and offal formed 39% of feeding observations for immatures, but only 17% for adult eagles.Two-thirds of our observations were in the upper St. Lawrence River, where deer carcasses on the ice accounted for 62% of feeding records.Contaminant exposure could be relatively low for wintering eagles feeding on prey of terrestrial origin compared to those feeding on aquatic mammals, ducks, gulls and fish.