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Threatened and Endangered Species: Bald Eagle Fact Sheet

Bald Eagle Haliaeetus leucocephalus Fact Sheet

OFFICIAL STATUS: Formerly Endangered, now delisted–Montana. Endangered species are species that are in danger of extinction throughout all or a significant portion of their range. It is unlawful to kill, harm, or harass endangered species.

LISTED: 43 Federal Register 6233; February 14, 1978 (Montana and 42 other states). Recovered, delisted and being monitored.

HISTORICAL STATUS: Bald eagles are thought to have historically nested in all of the lower 48 states. It is estimated that in the lower 48 states there were 50,000 breeding pairs of bald eagles in pre-colonial times. Due to human activities, this population reached a low of 400 breeding pairs in the early 1960s.

PRESENT STATUS: Bald eagles are abundant in Alaska and Canada. In 1990, there were approximately 2,500 breeding pairs in the lower 48 states. Major wintering areas for bald eagles occur along the lower reaches of the Mississippi, Missouri, and Illinois River systems, Florida, and the Pacific coast. In Montana, the number of breeding bald eagles has increased dramatically since 1980 and is above recovery objectives. Many eagles winter along Montana's major rivers and the tailrace areas of some reservoirs.

HABITAT: Bald eagles prefer forested habitats near bodies of water. Eagles concentrate near open water in the wintertime where fish and waterfowl are abundant. Migrating eagles are found throughout Montana.

LIFE HISTORY: Sexual maturity for eagles is reached at 4 to 6 years of age. Adults mate for life and tend to use the same nest year after year. The majority of nest sites are within 1/2 mile of water. Nests are usually at the top of tall trees, although cliffs are occasionally used. Nests can become enormous, weighing more than a ton. Usually 2 eggs are laid in a clutch. The eggs hatch after 35 days of incubation. Both parents assist in feeding the young. Young leave the nest after 75 days. Bald eagles feed on fish, waterfowl, and other birds, small mammals, and carrion.

AID to IDENTIFICATION: The white head and tail of mature bald eagles is an identifying characteristic. Immature birds are more difficult to identify. They are predominantly brown with an increasing amount of white mottling as the bird matures. The wingspan of 7 feet tends to distinguish the young birds from all other birds except the golden eagle.

REASONS for DECLINE: Bald eagle populations declined in the early 20th century due to loss of habitat, shooting, and trapping. During the 1950s and 1960s the use of pesticides, especially DDT, became a major problem. DDT residues accumulated in fish, a major food source of eagles. The residues then accumulated in the eagles that ate the fish and subsequently caused a thinning of eggshells. DDT is now banned in the United States. Shooting, trapping, poisoning, and human disturbance continue to be a problem. Bald eagles can be electrocuted when perching on power lines.

RECOMMENDATIONS: Minimize human activity during the breeding season within 1 mile of active nests. Wounded or sick eagles should be reported immediately to a wildlife agency. There are many rehabilitation centers throughout the country that can care for eagles. Report new nests to the state wildlife agency.

COMMENTS: In addition to being protected by the Endangered Species Act of 1973, the bald eagle is also protected by the Bald Eagle Protection Act of 1940. The bald eagle is the national symbol of the United States.

REFERENCES: Northern States Bald Eagle Recovery Plan by U.S. Fish and Wildlife Service, 1983.

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