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Haliaeetus leucocephalus

(White-Headed Sea Eagle)

Overview

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Adult bald eagles have dark bodies and wings with the familiar white head , neck, and tail feathers . Young eagles are less distinctive, adding the white feathers gradually after one year of age. Bald eagles are large birds, with body lengths of 28 to 32 inches and with wingspreads of 6 to 7 feet. Eagles catch and eat fish and other prey and will eat dead animals along lake and river shores and roadsides. Bald eagles nest in large trees , often near water. These nests are usually located near the tops of the tallest trees and are added to and re-used year after year. Generally, eagles nest in Alabama during October - May, but may stay on the nest until August.

Recovery Needs: Recovery needs for the bald eagle population include continued protection and management of their habitat , monitoring eagle populations, and re-establishing breeding populations throughout their historic range .

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Dutch:

Amerikaanse Zeearend

Common Names in English:

American Bald Eagle, American Eagle, Bald Eagle, Black Eagle, Fishing Eagle, Gray Eagle, Washington Eagle, Washington Sea-Eagle, White-Headed Eagle, White-Headed Sea Eagle

Common Names in French:

Pygargue à Tête Blanche, Pygargue à Tête Blanche

Common Names in German:

Weißkopf-Seeadler

Common Names in Japanese:

ãƒã‚¯ãƒˆã‚¦ãƒ¯ã‚·

Common Names in Russian:

Орлан белоголовый

Common Names in Spanish:

Águila Cabeza Blanca

Description

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Physical Description

Color:

Adults over four years old have a distinctive color pattern , with a white head and white tail, although the head can have some black flecking until at least seven years of age. During the first year, a Bald Eagle is all or mostly dark. After the first year, birds have variable mottling of "dirty white" feathers in their dark plumage until they reach adult plumage.

Adult: White head and upper neck · White tail · Dark brown body plumage · Yellow bill

Immature : Dark bill and dark cere · Dark brown body plumage, including head and tail · Variable amounts of white on underwing coverts, belly, and back · White head and tail, and dark underwings are gradually acquired in four years

Size/Age/Growth

About 34 to 43 inches long, with a wingspan of 72 to 96 inches. Adults weigh about 145.6 ounces .

79-94 cm (31-37 in) in length ; 178-229 cm (70-90 in) wingspan.

Habitat

Bald eagles require large trees or cliffs near water with abundant fish for nesting. They winter along oceans, rivers , lakes , or in areas where carrion is present.

Range-wide, bald eagles occur primarily in or near seacoasts, rivers, swamps , and large lakes (AOU 1998). It is considered a bird of aquatic ecosystems but within such areas, it must have an adequate food base , perching areas, and nesting sites to support them (Gerrard and Bortolotti 1988). Perching sites need to be composed of large trees or snags with heavy limbs or broken tops (USFS pers. Comm. 1999).

Vegetation: freshwater marshes, coastal waters, rivers • Maximum Elevation: 800 meters • Foraging Strata: Water • Center of Abundance: Lower subtropical: lowlands, lower than 500 m.; subtropics. • Sensitivity to Disturbancet: Medium

Ecology: List of Habitats : 5.1 Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls ) 9.1 Marine Neritic - Pelagic

Biology

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Diet

Fish predominate the typical diet of eagles, however, many other types of prey are also taken, including waterfowl and small mammals, and carrion especially in the wintering areas (USFWS 1995). It swoops from hunting perches , or soaring flight to pluck fish from water. It is also known to wade into shallow water to pursue fish. It may pounce on, or chase, injured or ice-bound water birds. In flooded fields , the species occasionally pounces on displaced voles, or other small mammals. Open, easily approached hunting perches and feeding areas are used most frequently (Zeiner, et al. 1990). Bald eagles tend to hunt cooperatively (Brown 1999). Studies of prey items in northern California, showed bald eagles do not differentiate between native and non-native freshwater fish species (Jackman, et al. 1999). One study of birds in Texas found them to eat a relatively equal proportion of birds, reptiles and fish (Mabie, et al. 1995). One wintering population in the lower Great Lakes basin was observed feeding on carcasses of white-tailed deer during 47% of observed feedings (Ewins and Andress 1995). The same group observed immature individuals feeding on garbage and offal 39% of feedings.

Reproduction

Breeding occurs in open areas, near water, with nests often in large snags or old-growth trees (Brown 1999). The bald eagle also nests in a dominant live tree with open branch work, especially ponderosa pine. It nests most frequently in stands with less than 40% canopy , but there is usually some foliage shading the nest (Call 1978). It often chooses the largest tree in a stand on which to build its stick platform nest. The nest may be a massive structure, twelve feet high, eight and a half feet across and with a wet mass of decaying vegetation in the center, weighing many hundred pounds (Brown and Amadon 1968). The nest is typically located 16-61 meters (50-200 ft ) above ground , usually below the tree crown. The species of tree that is used for locating the nest site is apparently not so important as the height and size. The nest is usually located near a permanent water source. In California, 87% of the nest sites were within 1.6 kilometers (1 mi ) of water. Individuals have been known to use the same nest for up to 35 years (Brown 1999). The clutch size is usually two, but can vary from one to three, and are laid once annually (Brown 1999). The bald eagle breeds from February through July, with a peak in activity from March to June. Incubation of the eggs usually lasts 34-36 days. The semi-altricial young hatch asynchronously (Ehrlich, et al. 1988). The species is monogamous, and breeds first at 4-5 yr (Zeiner, et al. 1990).

The breeding season begins in November and extends into May. The male and female build a very large, bulky nest out of twigs and sticks. The nest is usually built 9-18 m (30-60 feet) above the ground. Nesting sites include conifers, other trees, and cliffs . Bald Eagles maintain a long-term pair bond, and nests are sometimes reused many years in a row , with new material being added. One nest was used every year for 35 years. The female lays 1-3 (usually 2) eggs that she and the male incubate for 34-36 days. The young are semi-altricial, and leave the nest in 70-98 days.

Breeding Habitat: Wetland-open water Clutch Size: 2 Length of Incubation: 34-36 days Days to Fledge : 70-98 Number of Broods: 1

Migration

Migratory

Short distance migrant

Behavior

The Bald Eagle usually frequents areas near open water . In the winter many birds take advantage of dams that maintain open water, and bird densities in these areas are high. Fish are the primary food of the Bald Eagle. It captures fish by hunting from a perch until the prey comes by, by eating dead fish, or by taking fish from a neighboring gull, osprey, or other fish-eating animal. Eagles will often also eat waterfowl and rabbits.

Wintering bald eagles in New Mexico spent 95.3% of their time perched and 4.7% in flight (Zwank, et al. 1996). Of the time spent in flight, 13.0% was spent foraging (Zwank, et al. 1996). Winter feeding usually occurs immediately after dawn and in late afternoon (Zeiner, et al. 1990).

Survival: In one study of nests in British Colombia, Canada, food supply was identified as the “key factor ” in limiting breeding success (Elliot, et al. 1998). Because of the asynchronous hatching the older nestling may kill the younger, smaller sibling if the food supply is inadequate (Brown and Amadon 1968).

Socio-Spatial Behavior: Home range of resident pairs on the Columbia River averaged 22 km2 for both breeding and non-breeding periods (Garrett, et al. 1993). Breeding territory in Alaska (n= 14), varied from 11-45 hectares (28-112 ac), and averaged 23 hectares (57 ac) (Hensel and Troyer 1964). The breeding territory is defended from the mating through the fledging period of the pair. Minimum distances between nests were 1 kilometer (0.6 mi ) in Alaska, and 17 kilometers (10 mi) in Washington (Zeiner, et al. 1990).

Taxonomy

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Notes

Name Status: Accepted Name . Latest taxonomic scrutiny: 17-Oct-2001.

Similar Species

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Golden Eagle, Steller's Sea-Eagle

Immature Bald Eagles can be easily confused with the Golden Eagle and vultures from a distance. The Golden Eagle has banding on the tail and lacks the random splotchy white pattern of an immature Bald Eagle. The flight pattern of a Bald Eagle is distinctly different from that of a Turkey Vulture. The Bald Eagle soars with its wings horizontal or slightly drooped. The Turkey Vulture holds its wing tips up to form a "V." The Black Vulture is smaller, with a smaller head and shorter tail. The Black Vulture also has light patches on the outer portion of its wings.

Turkey Vulture has a tiny, unfeathered head, holds its wings in a dihedral, and has contrastingly paler flight feathers. Golden Eagle can be quite similar to immature Balds, or to adults at a distance but is all dark as an adult and as an immature has white restricted to the bases of the flight feathers and the bases of the tail feathers. The white is confined to crisp patches on the wing and tail, and is not blotchily scattered about underwings coverts as in immature Bald Eagles. Immature Golden Eagles have yellow ceres while immature Balds have dark ceres.

Members of the genus Haliaeetus

ZipcodeZoo has pages for 20 species and subspecies in this genus:

H. albicilla (Greenland White-Tailed Eagle) · H. albicilla albicilla (Greenland White-Tailed Eagle) · H. albicilla groenlandicus (Greenland White-Tailed Eagle) · H. albicillus · H. australis · H. calei · H. leucocephalus (White-Headed Sea Eagle) · H. leucocephalus alascanus (Northern Bald Eagle) · H. leucocephalus leucocephalus (White-Headed Sea Eagle) · H. leucocephalus ssp · H. leucocephalus washingtoniensis · H. leucogaster (White-Bellied Fish-Eagle) · H. leucoryphus (Band-Tailed Fish-Eagle) · H. pelagicus (Steller's Sea Eagle) · H. pelagicus niger · H. pelagicus pelagicus (Steller's Sea Eagle) · H. sanfordi (Solomon Islands Sea-Eagle) · H. vocifer (African Fish-Eagle) · H. vociferoides (Madagascar Fish-Eagle) · H. vocifer vocifer (African Fish-Eagle)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal March 03, 2008:

Identifiers

Footnotes

  1. New Mexico Wildlife. New Mexico Department of Game and Fish Version of April 24, 2009. [back]
Last Revised: 2009-12-02