Animal Fact Sheets

Life Span
Bald eagles may live 30 years or more in the wild and even longer in captivity

Diet
In the wild: Primarily fish when available, but will also hunt waterfowl and other aquatic birds, as well as small mammals. Bald eagles will also steal prey from other eagles and osprey, and feed on carrion.

At the zoo: Salmon, trout and quail

Reproduction
Bald eagles reach sexual maturity at 5 or 6 years of age and then form a pair bond and mate for life. After pairing, the birds construct a nest, or aerie, of sticks, branches and other plant material, in the fork of a large tree or cliff side. The nest may be used and added to year after year, eventually becoming a massive structure up to 9 feet (2.7 m) in diameter and weighing as much as 2,000 pounds (900 kg). Females lay a clutch of two, or occasionally three eggs, between November and mid-March. Incubation duties are performed by both parents but primarily by the female. Chicks hatch after a 34 to 35 day incubation.

Life Cycle
Young eagles remain at the nest for 10-12 weeks. At about 3 months of age the fledgling eagles are able to fly but the parents continue to feed and protect the young birds for another two to three months. Although young birds know instinctively how to hunt, lack of experience and skill means they often cannot catch adequate prey. Starvation, disease, bad weather and accidents, often due to human interference, mean that many young eagles do not survive their first year.

Bald With Feathers on Top
Bald eagles are not bald. The term bald comes from the Old English word "balde" (bal-duh) which means "white." The name "balde headed" eagle later became shortened to bald eagle. The white head and tail contrast sharply with the dark brown body of adult bald eagles, making them easy to distinguish from other large birds. Adults can also be distinguished by their pale yellow eyes; powerful yellow feet with long sharp talons; and sharply hooked yellow beak. The distinctive white head and tail are not attained until a bird reaches 4 to 6 years of age, consequently immature birds are often confused with golden eagles. Bald eagles are commonly called fish eagles because of the large proportion of fish in their diet which they catch by swooping down and thrusting their feet into the water. Even with powerful feet, sharp talons and textured, slip-resistant feet, bald eagles often miss their slippery prey. In addition to fish, bald eagles prey on ducks, geese and rabbits. Carrion such as spawned-out salmon, is especially important in winter when other food may be scarce.

All-American Bird
The bald eagle is a symbol of strength, independence and dignity, becoming the national bird of the United States in 1782. Wildlife experts estimate that at the time the bald eagle became our nation's symbol there may have been 25,000 to 75,000 nesting pairs of bald eagles in the lower 48 states. Many native American peoples admired bald eagles, and feathers are still used in tribal religious rites. Feathers must now be obtained by permit from the U.S. Fish and Wildlife Service which distributes them only for cultural or scientific purposes.

Location at the Zoo
Bald eagles can be seen at the zoo's Raptor Center and at the Northern Trail. Other raptors at the Raptor Center include: gyrfalcon, Harris's hawk, turkey vulture as well as snowy, spectacled and barred owls. A spotted owl and barn owl can also be found in the Temperate Forest.

Conservation Connection
Bald eagles were delisted by the US government from the endangered species list on June 29, 2007.* By the early 1900s, bald eagle numbers had declined significantly due to shooting and habitat destruction. In 1940, bald eagles faced a new threat when the pesticide DDT was introduced to the environment. DDT built up in the food chain and accumulated in tissues of many top predators. Pesticide accumulation caused them to lay abnormally thin-shelled eggs, which often broke during incubation. With a sharp decline in reproductive success, bald eagle populations disappeared from many states. In 1963, only 417 eagles were found in the lower 48 states.

In 1978, the U.S Fish and Wildlife Service declared the bald eagle endangered under the Endangered Species Act. By 1995, the lower 48-states population approached 5,000 nesting pairs, and the bald eagle was downlisted from endangered to threatened. In 1998, about 600 nesting pairs were counted in Washington state. Of interest, in 1989, for the first time in decades, eagles nested in Seattle's Discovery Park.

When DDT was banned in 1972 after scientists discovered the chemicals negative effect on eagle eggs, bald eagle reproductive success began to improve. Protective laws and intensive efforts by federal agencies assisted bald eagle recovery. Private, local and state agencies assisted by acquiring important nesting and wintering habitat such as the Skagit River Bald Eagle National Area in Skagit County, Washington.

Woodland Park Zoo began the rehabilitation of injured and sick eagles in 1971. Since that time more than 200 bald and golden eagles, peregrine falcons and other birds of prey have been received. More than 70 eagles and many of the other birds were rehabilitated and returned to the wild. The eagles at Woodland Park Zoo are wild birds that were brought here because of injuries and cannot be released. If a bird cannot be released, it is sent to a wildlife facility that will use it to educate people about birds of prey.

Bald eagle numbers have increased significantly in recent years, and in 1995 the bald eagle was upgraded to threatened status on the federal list of Endangered and Threatened Wildlife and Plants throughout most of its range. With more than 10,000 pairs, the eagle was removed from the endangered list on June 29, 2007. Despite this, eagles are still at risk from habitat destruction and other factors.

How You Can Help!
Efforts to save threatened and endangered raptors require cooperation and support at international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice.

Contact the Woodland Park Zoo at webkeeper@zoo.org to find ways you can support conservation programs at the zoo. Discover more about raptors by calling the Peregrine Fund (208) 362-3716. Learn other ways you can help conserve wildlife and their habitats by visiting our 
How You Can Help page.

Sources and Suggested Reading
Clark, William S., and Brian K. Wheeler. 1987. A Field Guide to Hawks of North Americas. Houghton Mifflin Co., Boston, MA. 198 p.

Johnsgard, Paul A. 1990. Hawks, Eagles, & Falcons of North America. Smithsonian Institution, Washington, DC. 403 p.

For Kids!
Gieck, Charlene. 1991. Eagles for Kids. NorthWord Press, Minocqua, WI. 48 p.

Zoobooks. 1986. Birds of Prey. Wildlife Education, Ltd., San Diego, CA. 16 p.