Size - The female bald eagle is 35 to 37 inches, slightly larger than the male. With a wingspan which varies from 79 to 90 inches. The male bald eagle has a body length from 30 to 34 inches. The wingspan ranges from 72 to 85 inches. Bald eagles weigh from ten to fourteen pounds.
Northern birds are significantly larger than their southern relatives.
Wild bald eagles may live as long as thirty years, but the average lifespan is probably about fifteen to twenty years Eagles sit at the top of the food chain , making them more vulnerable to toxic chemicals in the environment, since each link in the food chain tends to concentrate chemicals from the lower link. Tolerance to cold temperatures - A bald eagle's skin is protected by feathers lined with down. The feet are cold resistance because they are mostly tendon. The outside of the bill is mostly nonliving material, with little blood supply. Fidelity - Once paired, bald eagles remain together until one dies, the survivor will not hesitate to accept a new mate.