Habitat
Bald eagle habitat varies
throughout their range, however, bald eagles are generally found
in coastal areas or near large inland lakes and rivers where fish
are abundant and large trees are available for nesting. |
Wingspan
Adult male: 6-6.5 feet (1.80-1.95 m)
Adult female: 6.5-7.5 feet (1.95-2.25 m) |
Weight
Adult male: 8-10 pounds (3.6-4.5 kg)
Adult female: 10-14 pounds (4.5-6.3 kg) |
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 |
If you
like this animal and find it particularly fascinating you
can adopt it!
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.
|
Fascinating
Facts
-
Eagles have excellent eyesight
and may be able to see six to eight times better than humans!
-
The
Latin word "raptare" means
to grab or seize. Eagles are called raptors because they
use their feet to catch and kill their food!
|

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.

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.
*Woodland Park Zoo identifies an animal
or plant endangered if it is listed as endangered (in any part
of its range) on the federal list of Endangered and Threatened
Species, or if is listed on Appendix 1 of the Convention on International
Trade in Endangered Species of Wild Fauna and Flora (CITES). |