Bald Eagle Information
(Haliaeetus leucocephalus)
Bald Eagle Information | ||||
(Haliaeetus leucocephalus) | ||||
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You will shortly hear the sound of several bald eagles recorded in Homer, Alaska. Order: Family: Accipitridae (ospreys, harriers, hawks) Body: Bald eagles are large raptors and are the only eagle unique to North America. A mature male eagle averages 3 feet in length and has a wingspan of around 6.5 feet. A mature female can be up to 43 inches in length and can have a wingspan of 8 feet. Males generally weigh from 7 to 10 pounds while females can weigh up to 14 pounds. The eagle has large, pale eyes which have a clear nictitating membrane that sweeps across the surface of the eye every few seconds to keep it moist and clean. They have a large, curved yellow beak that is powerful enough to tear flesh from a carcass. Their legs are yellow in color and have sharp, curved black talons to allow this raptor to pick up and carry off its prey. The distinctive white capped and tailed eagle that is representitive of our country does not start out life looking this way. On average, an eagle will develope its all white head and tail feathers after its fourth or fifth year. An immature bald eagle, one under 4 or 5 years old, will sport mottled brown plummage. As it nears maturity, the head and tail feathers begin to gradually molt to white. A bald eagle is often its largest body size and weight during this immature stage of life. Diet: The bald eagle is a raptor and ideally will catch its own prey. Its primary food is fish, but it will also eat rabbits, rodents, ducks, seagulls, and even snakes. Eagles are powerful raptors but are also scavengers and will eat carrion and even trash, if it is available. Eagles migrate in large numbers during the winter to streams and open water areas where prey is plentiful. One of the largest natural winter gatherings of eagles occures in Haines, AK. Another town in Alaska, Homer, is famous for its winter eagles as Jean the Eagle Lady has been feeding a gathering of hundreds for many years now. A major cause of death, especially for immature eagles, is starvation due to lack of food. Range: The bald eagle is native to North America and has historically ranged from the northern reaches of Alaska and Canada down to northern Mexico. An eagle needs isolated habitat with old growth timbers and pristine waters. They nest in the tops of trees located near rivers, lakes, and wetland areas. Challenges: The bald eagle has faced many challenges from man over the last 200 or so years and was nearly extinct over most of its range as recently as 30 years ago. Man has threatened the bald eagles reign as the sovereign symbol of our country through habitat destruction, illegal hunting and shooting, and contamination of its food sources. Many farmers and ranchers felt that eagles were a threat to their livestock, so the birds were slaughtered in large numbers. The pesticide DDT, as well as spent lead shot used by hunters, have both have major impacts on the food sources of the eagle. DDT was sprayed on crops throughout the country for years and was eventually found to be a major cause of death for eagles as well as other birds, such as the Peregrine Falcon. The DDT was injested by fish which were in turn eaten by the birds. The pesticide interfered with the formation of strong egg shells to the extent that the shells were too thin and were either crushed by the incubating female or failed to hatch. In 1782, the year the bald eagle was declared the national symbol, there were up to 75,000 nesting pairs in the lower 48 states, but by the early 1960's, there were fewer than 450 breeding pairs. In 1940, Congress passed the Bald Eagle Protection Act making it illegal to kill, harass, possess (without a permit), or sell bald eagles. In 1967, bald eagles were officially declared an endangered species, and in 1973, The Endangered Species Act formalized this designation A major step in the restoration of eagle populations was the formation of the Patuxent Wildlife Research Center near the Patuxent River in Maryland. This center was responsible for the hatching of 124 bald eagles which were used to set up breeding pairs throughout the country. In July of 1995, due to their dramatic recovery, the bald eagle was no longer considered Endangered and it's official designation was changed to ONLY Threatened. Endangered means that a species is considered in danger of extinction in all of, or most of its range, while a designation of Threatened means that a species is likely to become endangered, but not in danger of extinction. The eagle and other birds are not out of danger yet, as habitat destruction continues and DDT has been reintroduced in parts of South America. Life History: Bald eagles choose a mate for life and build huge nests in the tops of large trees near river or wetlands. The same eagles may use a nest for years and will continually add on the the nest each year. It is not uncommon for an eagle nest to reach 10 feet in diameter and weigh up to 1000 pounds. Eagles may travel great distances throughout the year, but usually return to nest within 100 miles of where they were born. The female lays tow to three eggs, and after a 35 day gestation period, they give birth to their young in late May or early June. An eagle chick can fly within three months and they are usually on their own within four months. Chicks have a poor survival rate due to disease, starvation, foul weather, or human interference, and only about one half will reach adulthood, An eagle can live 30 years or longer in the wild , and they have been known to live even longer in captivity. | |||||||
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