Bald eagles were large raptors native to northern coasts, river systems, and inland lakes. Larger than other Eagles, they had wingspans that commonly reached seven to eight feet and weighed between six and fourteen pounds depending on region and available prey. Their white heads and dark body feathers were not present until maturity. Juveniles showed mottled brown patterns and were often mistaken for entirely different species. They fed primarily on fish, but also took small mammals or birds if opportunity allowed.
They nested in high trees near water and reused these nests for many years which produced some of the largest recorded nest masses of any bird. Bald eagles defended their immediate territory with fast aerial strikes and loud calls. These pressure displays usually forced intruders to flee, but prolonged standoffs sometimes led to torn wings or broken bone. Their populations fluctuated in cycles depending on prey abundance and the health of water systems around their nesting range.