Adults measure from 30 to 40 inches from head to tail, with a 7-8 foot wingspan, and weigh from 8 to 14 pounds. The female is larger than the male. The distinctive white head and tail feathers appear when the eagles mature at 4 or 5 years old. Bald eagles are believed to live 30 years or longer in the wild.
They mate for life, building huge nests in the tops of large trees near rivers, lakes, and other wetlands. The adults will often return to the same nest year after year making additions to the nest each year. Some nests can reach up to 10 feet across and weigh up to 2000 pounds.
Eagles feed primarily on fish, but will also feed on ducks, rodents, snakes, and carrion.
Both the male and female build the nest, but the female chooses the nest tree. Both will defend the nest territory which is usually several square miles, depending on habitat and the proximity of other nesting eagles.
The female will lay 1 to 3 (usually 2) eggs 2 to 3 days apart. The eggs are about 3 inches long and are an off-white color. Incubation is done by both parents and lasts about 35 days.
The young will stay in the nest about 11 to 12 weeks when the adults will start encouraging them to fly. The eaglets can often be seen exercising their wings on the nest or on a nearby branch several days prior to fledging (first flight from the nest).
The young will stay at or near the nest for the next 6 weeks while the adults continue to feed them and teach them to hunt and fish on their own. Young eagles are believed to return to within 100 miles or so of their own nest site when they reach maturity and are ready to mate.
Bald eagle populations started to decline in the late 1940's coinciding with the introduction of the pesticide DDT. Breeding pairs dropped to about 450 in the lower 48 states. This led to their being designated as an endangered species in 1978. The use of DDT in the United States was banned in 1972. This and other recovery efforts have helped the bald eagle to recover. They were downgraded to threatened status in 1995. On August 9, 2007, the bald eagle was removed from the federal list of threatened and endangered species. A wintering population survey of North America in 1997 resulted in a count of 96,648 individuals, with about 75% occurring in Alaska and British Columbia. Bald eagle populations have been increasing in recent years. Have you seen one?
REF: U.S. Fish and Wildlife Service - www.fws.gov