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Bald Eagle
Haliaeetus leucocephalus

General Information

Official Status: De-listed, the bald eagle has been de-listed throughout it range in the lower 48 states, except for the Sonoran Desert distinct population segment in portions of Arizona, where it remains threatened status.

Date listed: The Department of the Interior first listed the bald eagle as a threatened species on March 11, 1967, under the Endangered Species Preservation Act of 1966.

Date de-listed:The Fish and Wildlife Service removed the bald eagle from the list of threatened and endangered species, effective August 8, 2007.

The Service has also drafted a post de-listing monitoring plan for the bald eagle, and requests public comments on or before October 9, 2007.

Critical Habitat:

Critical habitat has not been designated for the bald eagle.

Recovery Plan: Five recovery plans have been prepared and implemented for the bald eagle, nation-wide. Each recovery plan applies to bald eagle populations within a large geographic area of the U.S. with similar management needs and species status. The Pacific Bald Eagle Recovery Plan (pdf, 5.5 MB) applies within northwestern California.


Bald Eagle in Flight Photograph, NCTC Library Image, USFWS


Photo Credit: NCTC Image Library, USFWS

arrow button Photo Gallery for the Bald Eagle

Identifying Characteristics:

A large raptor (bird of prey), the bald eagle has a wingspread of 5½ to 8 feet. Adults have a dark brown body and wings, white head and tail, and a yellow beak. In flight, the bald eagle often soars or glides with the wings held at a right angle to the body. Juvenile bald eagles have mottled brown and white plumage, gradually acquiring their dark brown body and distinctive white head and tail as they mature. Bald eagles generally attain adult plumage by 5 years of age. Adults weigh 8 to 14 pounds, occasionally reaching 16 pounds in Alaska. Those in the northern range grow larger than those in the south, and females are somewhat larger than males.

Current Geographic Range:

Bald eagles are a North American species that historically occurred throughout the contiguous United States and Alaska. After severely declining in the lower 48 States between the 1870s and the 1970s, bald eagles have rebounded and re-established breeding territories in each of the lower 48 states except Vermont. The largest North American breeding populations are in Alaska and Canada, but there are also significant bald eagle populations in Florida, the Pacific Northwest, the Greater Yellowstone area, the Great Lakes States, and the Chesapeake Bay region. Bald eagle distribution varies seasonally. Bald eagles that nest in southern latitudes frequently move northward in late spring and early summer, often summering as far north as Canada. Most eagles that breed at northern latitudes migrate southward during winter, or to coastal areas where waters remain unfrozen.

Life History:

Bald eagles can live 15 to 25 years in the wild, and even longer in captivity. Most are capable of breeding at 4 or 5 years of age, but in dense populations they may not start breeding until much older. A pair typically mates for life and builds a huge nest in the tops of large trees near rivers, lakes, marshes, or other aquatic areas. Nests are often re-used year after year, with additions to the nests made annually. Nests are often 4 to 6 feet wide and may weigh up to 1,000 pounds. Although bald eagles may range over great distances, they usually return to nest within 125 miles of where they were raised.

Nesting activity begins several weeks before egg-laying. Egg-laying dates vary throughout the U.S., ranging from October in Florida, to late April or even early May in the northern United States. The bald eagle nesting season tends to be longer in the southern U.S., and re-nesting following nest failure is more common there as well. In the Pacific Northwest, nest construction begins around January 1, and females typically initiate egg laying soon after February 1. Bald eagles lay one to four eggs a year (typically 2), which hatch after about 35 days of incubation. Only one egg is laid per day, and not always on successive days. Hatching of young occurs on different days, with the result that chicks in the same nest are sometimes of unequal size. Eaglets make their first unsteady flights about 10 to 12 weeks after hatching, and fledge (leave their nests) within a few days after that first flight. However, young birds usually remain in the vicinity of the nest for several weeks after fledging because they are almost completely dependent on their parents for food until they disperse from the nesting territory approximately 6 weeks later. Recent studies show that approximately 70 percent survive their first year of life.

In winter, eagles that nest in northern areas often migrate south and gather in large numbers near open water areas where fish and other prey are plentiful.

Bald eagles are opportunistic feeders. Fish comprise much of their diet, but they also eat waterfowl, shorebirds/colonial waterbirds, small mammals, turtles, and carrion (often along roads or at landfills). Because they are visual hunters, eagles typically locate their prey from a conspicuous perch, or soaring flight, then swoop down and strike. Wintering bald eagles often congregate in large numbers along streams to feed on spawning salmon or other fish species, and often gather in large numbers in areas below reservoirs, especially hydropower dams. Wintering eagles also take birds from rafts of ducks at reservoirs and rivers, and congregate on melting ice shelves to scavenge dead fish and waterfowl from the current or the soft melting ice.

During the nesting season, adults carry prey to the nest to feed the young. Adults feed their chicks by tearing off pieces of food and holding them to the beaks of the eaglets. After fledging, immature eagles are slow to develop hunting skills, and must learn to locate reliable food sources and master feeding techniques. Young eagles will congregate together, often feeding upon easily acquired food such as carrion and fish found in abundance at the mouths of streams and shallow bays and at landfills.

Bald eagle distribution varies seasonally. Bald eagles that nest in southern latitudes frequently move northward in late spring and early summer, often summering as far north as Canada. Most eagles that breed at northern latitudes migrate southward during winter, or to coastal areas where waters remain unfrozen. Migrants frequently concentrate in large numbers at sites where food is abundant and they often roost together communally. In some cases, concentration areas are used year-round: in summer by southern eagles and in winter by northern eagles. Migrants frequently concentrate in large numbers at sites where food is abundant, and they often roost together communally. In some cases, concentration areas are used year-round.

General Habitat Characteristics:

Bald eagles generally nest near coastlines, rivers, large lakes or streams that support an adequate food supply. They often nest in mature or old-growth trees; snags (dead trees); cliffs; rock promontories; rarely on the ground; and with increasing frequency on human-made structures such as power poles and communication towers. In forested areas, bald eagles often select the tallest trees with limbs strong enough to support a nest that can weigh more than 1,000 pounds. Nest sites typically include at least one perch with a clear view of the water where the eagles usually forage. Shoreline trees or snags located near reservoirs provide the visibility and accessibility needed to locate aquatic prey. Eagle nests are constructed with large sticks, and may be lined with moss, grass, plant stalks, lichens, seaweed, or sod. Nests are usually about 4-6 feet in diameter and 3 feet deep, although larger nests exist.

Breeding bald eagles occupy “territories,” areas they will typically defend against intrusion by other eagles. In addition to the active nest, a territory may include one or more alternate nests built or maintained by the eagles but not used for nesting in a given year. Bald eagles exhibit high nest site fidelity and nesting territories are often used year after year. Some territories are known to have been used continuously for over half a century.

Population and Habitat Status:

Bald eagles are a North American species that historically occurred throughout the contiguous United States, Alaska, Canada, and northern Mexico. After severely declining in the lower 48 States between the 1870s and the 1970s, bald eagles have rebounded and re-established breeding territories in each of the lower 48 States except Vermont. The largest North American breeding populations are in Alaska and Canada (where they are not listed as threatened), but significant bald eagle populations also occur in Florida, the Pacific Northwest, the Greater Yellowstone area, the Great Lakes States, and the Chesapeake Bay region.

Wildlife experts estimate that as many as 100,000 bald eagle pairs nested in the lower 48 states when the bird was adopted by Congress in 1787 as our national emblem. Since that time, the bald eagle has suffered from habitat destruction and degradation, illegal shooting, and contamination of its food, most notably due to the pesticide DDT. By 1963, biologists counted only 417 bald eagle nesting pairs in the lower 48 states.

Recent population estimates by the Fish and Wildlife Service indicate the following numbers of breeding pairs of bald eagles within states covered by the Pacific Bald Eagle Recovery Plan: California, 160; Idaho, 128; Montana, 216; Nevada, 2; Oregon, 405; Washington, 658; and Wyoming, 89.

The overall national fledging rate is approximately one chick per nest, annually, which amounts to a healthy, expanding population. Nation-wide, with few exceptions, the species has shown a gradual and continuing upward trend in number of nesting pairs per state. State-by-state population trends for breeding pairs during the period 1990 through 2003 can be found in the table downloaded at the following web site: http://www.fws.gov/midwest/eagle/population/nos_state_tbl.htm.

Threats:

The greatest threat to the bald eagle’s existence arose from the widespread use of DDT and other pesticides after 1940. DDT was used extensively for insect control throughout the country and in other parts of the world, and its residues washed into lakes and streams. Once in the aquatic environment, it was absorbed by plants and invertebrates that were eaten by fish. The contaminated fish, in turn, were consumed by bald eagles. The chemical DDT, and its primary metabolite DDE, interfered with the bald eagle’s ability to develop strong shells for its eggs. As a result, bald eagles and other bird species such as brown pelicans and peregrine falcons began laying eggs with shells so thin they often broke during incubation, or otherwise failed to hatch. Their reproduction disrupted, bald eagle populations plummeted.

As the dangers of DDT became known, in large part due to Rachel Carson’s famous book Silent Spring, this pesticide was banned in 1972 for most uses in the U.S. In addition to the adverse effects of DDT, bald eagles also died from lead poisoning as a result of feeding on hunter-killed or crippled waterfowl containing lead shot and from lead shot that was inadvertently ingested by the waterfowl. In 1991, a 5-year program to phase out the use of lead shot for waterfowl hunting was completed by the Service.

Disruption, destruction, or obstruction of roosting and foraging areas can also negatively affect bald eagles. Nesting bald eagles may inadequately feed their young if the adults are prevented or discouraged from feeding at preferred sites. Migrating and wintering bald eagles congregate at specific sites for purposes of feeding and sheltering. Bald eagles rely on established roost sites because of their favorable proximity to sufficient food sources. Bald eagles usually select roost sites in mature trees where they are somewhat sheltered from the wind and inclement weather. Human activities near or within communal roost sites may prevent eagles from feeding or taking shelter, especially if other undisturbed and productive feeding and roosting sites are unavailable. Disruptive activities in the flight path between nesting and roosting sites and nearby foraging areas can interfere with feeding. Activities that permanently alter eagle habitat can altogether eliminate the elements that are essential for feeding and sheltering eagles.

Bald eagles’ penchant for feeding on roadkill and euthanized animal carcasses at landfills and feedlots can be deadly: collision with cars and secondary poisoning by ingestion of sodium pentobarbital are both significant causes of eagle mortalities.

Human activity may agitate or bother roosting or foraging bald eagles to the degree that interferes with or interrupts their breeding, feeding, or sheltering behavior, causing injury, death, or nest abandonment. If activities you propose to conduct potentially disturb roosting or foraging bald eagles, please contact your local Fish and Wildlife Service Field Office for advice and recommendations to avoid such disturbance, based on site-specific information.

Conservation Needs:

Full recovery and eventual delisting of the species depends on continued protection of the bald eagle and its habitat. The pesticide DDT remains a restricted chemical. With continued control, DDT and its residual products are gradually disappearing from the bald eagle’s habitat and prey species. Maintenance of bald eagle nest and roost sites, and regrowth of forest stands for additional sites, should provide for future populations of the species throughout its listed range. Disturbance at nesting and roosting sites, such as from waterborne recreational activities and motorized craft, continue to be a potential threat. The Service continues to work on appropriate recommendations for management of nesting and roosting sites where disturbance to bald eagles may be a problem. Ongoing efforts to reduce the risk to eagles from auto collisions, electrocution at power lines, and inadvertent poisoning should continue.

National Bald Eagle Management Guidelines Document

 

The Service has adopted new regulations which provide protections from disturbance to bald and golden eagles, consistent with the Bald and Golden Eagle Protection Act. These regulations provide clear and consistent guidelines on the definition of "disturb" as it applies to these species. The definition of "disturb" document.

Related Documents:
Other Informational Weblinks:

 

Last updated: April 20, 2011

Arcata Fish and Wildlife Office, 1655 Heindon Road, Arcata, California 95521, USA
Tel: (707) 822.7201 Fax: (707) 822.8411