BALD EAGLE

Kingdom: Animalia
Phylum: Chordata
Class:  Aves
Order: Falconiformes
Family: Accipitridae
Genus: Haliaeetus
Species: Haliaeetus leucocephalus

Bald eagles are one of the large birds of prey native to North America, with a wingspan of about 7 feet (2 meters). (They are second in size only to the California condor and are about the same size as the golden eagle.) These regal-looking birds aren't really bald, but their white-feathered heads gleam in contrast to their chocolate-brown body and wings. Their legs and bills are bright yellow.

The Bald Eagle has been the national emblem of the United States since 1782 and a spiritual symbol for native people for far longer than that. These regal birds aren’t really bald, but their white-feathered heads gleam in contrast to their chocolate-brown body and wings. Look for them soaring in solitude, chasing other birds for their food, or gathering by the hundreds in winter. Once endangered by hunting and pesticides, Bald Eagles have flourished under protection.

• • Size & Shape

    The Bald Eagle dwarfs most other raptors, including the Turkey Vulture and Red-tailed Hawk. It has a heavy body, large head, and long, hooked bill. In flight, a Bald Eagle holds its broad wings flat like a board.

  • Color Pattern

    Adult Bald Eagles have white heads and tails with dark brown bodies and wings. Their legs and bills are bright yellow. Immature birds have mostly dark heads and tails; their brown wings and bodies are mottled with white in varying amounts. Young birds attain adult plumage in about five years.

  • Behavior

    You'll find Bald Eagles soaring high in the sky, flapping low over treetops with slow wingbeats, or perched in trees or on the ground. Bald Eagles scavenge many meals by harassing other birds or by eating carrion or garbage. They eat mainly fish, but also hunt mammals, gulls, and waterfowl.

  • Habitat

    Look for Bald Eagles near lakes, reservoirs, rivers, marshes, and coasts. For a chance to see large Bald Eagle congregations, check out wildlife refuges or large bodies of water in winter over much of the continent, or fish processing plants and dumpsters year-round in coastal Alaska and the Pacific Northwest.

    
    

    Cool Facts

    
    

    Rather than do their own fishing, Bald Eagles often go after other creatures’ catches. A Bald Eagle will harass a hunting Osprey until the smaller raptor drops its prey in midair, where the eagle swoops it up. A Bald Eagle may even snatch a fish directly out of an Osprey’s talons. Fishing mammals (even people sometimes) can also lose prey to Bald Eagle piracy. See an example here.

    
    

    

    Had Benjamin Franklin prevailed, the U.S. emblem might have been the Wild Turkey. In 1784, Franklin disparaged the national bird’s thieving tendencies and its vulnerability to harassment by small birds. "For my own part,” he wrote, “I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly. … Besides he is a rank Coward: The little King Bird not bigger than a Sparrow attacks him boldly and drives him out of the District.”

    
    

    Bald Eagles suffered in the March 1989 Exxon Valdezoil spill in Prince William Sound, Alaska. An estimated 247 Bald Eagles died from oil exposure and population levels in the Sound decreased by almost four percent the following year. The local population returned to pre-spill levels by 1995.

    
    

    Sometimes even the national bird has to cut loose. Bald Eagles have been known to play with plastic bottles and other objects pressed into service as toys. One observer witnessed six Bald Eagles passing sticks to each other in midair.

    
    

    The largest Bald Eagle nest on record, in St. Petersburg, Florida, was 2.9 meters in diameter and 6.1 meters tall. Another famous nest—in Vermilion, Ohio—was shaped like a wine glass and weighed almost two metric tons. It was used for 34 years until the tree blew down.

    
    

    Immature Bald Eagles spend the first four years of their lives in nomadic exploration of vast territories and can fly hundreds of miles per day. Some young birds from Florida have wandered north as far as Michigan, and birds from California have reached Alaska.

    
    

    Bald Eagles can live a long time, with a longevity record of 28 years in the wild and 36 years in captivity.

    
    

    Bald Eagles occasionally hunt cooperatively, with one individual flushing prey towards another.

    
    

    

    HABITAT

    Bald Eagles typically nest in forested areas adjacent to large bodies of water, staying away from heavily developed areas when possible. Bald Eagles are tolerant of human activity when feeding, and may congregate around fish processing plants, dumps, and below dams where fish concentrate. For perching, Bald Eagles prefer tall, mature coniferous or deciduous trees that afford a wide view of the surroundings. In winter, Bald Eagles can also be seen in dry, open uplands if there is access to open water for fishing.

    
    

    FOOD
    

    

    Fish of many kinds constitute the centerpiece of the Bald Eagle diet (common examples include salmon, herring, shad, and catfish), but these birds eat a wide variety of foods depending on what’s available. They eat birds, reptiles, amphibians, invertebrates such as crabs, and mammals including rabbits and muskrats. They take their prey live, fresh, or as carrion. Bald Eagles sometimes gorge, ingesting a large amount of food and digesting it over several days. They can also survive fasting for many days, even weeks.

    
    

    Nesting

    Nesting Facts

    Clutch Size

    1–3 eggs

    Number of Broods

    1 broods

    Egg Length

    2.3–3.3 in
    5.8–8.4 cm

    Egg Width

    1.9–2.5 in
    4.7–6.3 cm

    Incubation Period

    34–36 days

    Nestling Period

    56–98 days

    Egg Description

    Dull white, usually without markings.

    Condition at Hatching

    Covered with light-gray down; eyes brown; gape, legs, and skin pink.

    NEST DESCRIPTION

    Bald Eagles build some of the largest of all bird nests—typically 5 to 6 feet in diameter and 2 to 4 feet tall, and ranging in shape from cylindrical to conical to flat, depending on the supporting tree. Both sexes bring materials to the nest, but the female does most of the placement. They weave together sticks and fill in the cracks with softer material such as grass, moss, or cornstalks. The inside of the nest is lined first with lichen or other fine woody material, then with downy feathers and sometimes sprigs of greenery. Ground nests are built of whatever’s available, such as kelp and driftwood near coastal shorelines. Nests can take up to three months to build, and may be reused (and added to) year after year.

    

     NEST PLACEMENT - Bald Eagles nest in trees except in    regions where only cliff faces or ground sites are available. They tend to use tall, sturdy conifers that protrude above the forest canopy, providing easy flight access and good visibility. In southern parts of their range, Bald Eagles may nest in deciduous trees, mangroves, and cactus. It’s unknown whether the male or the female takes the lead in selecting a nest site. Nests are typically built near the trunk, high up in the tree but below the crown (unlike Osprey nests).

    
    

    
    

    
    

    
    BEHAVIOUR

    Bald Eagles are powerful fliers—soaring, gliding, and flapping over long distances. In one of several spectacular courtship displays, a male and female fly high into the sky, lock talons, and cartwheel downward together, breaking off at the last instant to avoid crashing to earth. Bald Eagles frequently harass birds including Ospreys and other eagles to steal their food, and occasionally do the same to mammals such as river or sea otters. On the ground, Bald Eagles walk in an awkward, rocking gait. Capable of floating, a Bald Eagle may use its wings to “row” over water too deep for wading. Though often solitary, Bald Eagles congregate by the scores or even the hundreds at communal roosts and feeding sites, particularly in winter. These groups can be boisterous, with birds jostling for position and bickering over prey. During breeding season you may see Bald Eagles defending their territories from a variety of intruders, including raptors and ravens, coyotes and foxes. When feeding at carcasses, Bald Eagles may push Black and Turkey Vultures out of the way; other species including ravens, coyotes, bobcats, and dogs sometimes hold their own. Bald Eagles are often harassed or chased by their fellow raptors and by songbirds including blackbirds, crows, and flycatchers.

    
    SOURCE CREDITS

    Buehler, D. A. 2000. Bald Eagle (Haliaeetus leucocephalus). In The Birds of North America, No. 564 (A. Poole and F. Gill, eds.). 

    Dunne, P. 2006. Pete Dunne’s Essential Field Guide Companion. Houghton Mifflin, New York.

    Cornell Lab of Ornithology

    Birdhouses 101

    Live Science