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The bald eagle is one of the most easily recognized birds in North America, with its bright white head and tail. The term "bald" does not refer to the eagle appearing "hairless," the word actually once meant "white," and both sexes sport the characteristic white head. Feet and bill are yellow in both sexes.
Juvenile bald eagles lack the characteristic white head and tail feathers, which do not appear until about five years of age. Until then the only way to distinguish a juvenile bald eagle from a golden eagle is to look at the legs, which are bare in bald eagles and fully feathered in golden eagles.
Females are 35-37 inches long, have a wingspan of 79-90 inches, and weigh about 14 pounds; males are 30-34 inches long, have a wingspan of 72-85 inches, and weigh about 10 pounds.
Like all other birds of prey, the bald eagle has excellent eyesight. It also has good color vision, and can see both forward and to the side at the same time. It is capable of flying up to 35 miles per hour, to an altitude of 10,000 feet, and often takes advantage of thermals when travelling long distances.
Distribution and Habitat
Bald eagles are most commonly seen in Alaska, Canada, and around the Gulf of Mexico, with flocks often appearing in other regions of the continental United States on a seasonal basis. Northern populations often migrate southward as rivers and lakes freeze over in their native habitats, but do so in response to moving food supplies rather than because of cold weather. In both native and migratory habitats the bald eagle is almost always found near the coast, or along a large lake or major river that remains ice-free.
Bald eagles feed primarily on fish, but will also take a variety of small mammals, waterfowl, and carrion. They exhibit a wide variety of fishing and hunting habits, ranging from taking prey while flying overhead to simply pouncing from ambush. Bald eagles are also notorious for stealing food from other birds, especially ospreys and fellow bald eagles. They can open and close their powerful, sharp talons at will, and are capable of lifting up to four pounds.
Bald eagles mate for life, but if one mate dies the other will seek a new one. They return to the same nest year after year, making repairs and additions as needed. If the nest is destroyed the pair will build a new one; if possible it will use the same tree or rocky cliff, but if not it will build as close to the original site as possible, even if humans have encroached on the area. The nest itself is made of sticks up to six feet long, usually lined with weeds, stubble and earth. A new nest may be up to five feet in diameter, while older nests have been known to reach a diameter of nine feet and more. High trees are preferred, but bald eagles will also nest on high rocky cliffs or pinnacles, and will also take advantage of special nesting platforms provided for them by humans.
Breeding season runs from January through March in the north, September through November in the south. Two or three white or pale blue eggs, each about 2-3/4 inches long, are laid five to ten days after mating, generally a day or two apart. The eggs are incubated by both parents for about 35 days. Chicks are snowy white in color, very weak, and have limited vision, but mature fairly rapidly. Although the parents will feed all chicks in the nest, the oldest one will typically bully its nestmate(s) until it has the nest to itself. The parents will continue caring for the remaining chick until it is fully fledged, at about 15-20 weeks of age, and will then chase it away. The parents will teach the chick how to fly, but will not teach it how to hunt, that is something the youngster must learn on its own.
Bald eagles become sexually mature at about five years, and can live up to 30 years in the wild.
Once threatened throughout North America due to habitat destruction and the use of pesticides and other chemicals (which damaged the eggs and entered adults via their food), the bald eagle was officially taken off the Endangered Species List on June 28, 2007. It is still protected under the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act, however. The bald eagle has been the national bird of the United States since 1782.
Site of Interest
American Bald Eagle Information www.baldeagleinfo.com
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This page was last updated on August 31, 2018.