why do they call a bald eagle a bald eagle
Good question. Bald eagles are actually not bald at all. The word bald is an archaic old world reference from the word piebald meaning marked with white. Mature Bald eagles have white feathered heads and approximately 7,000 feathers, in layers that trap air to insulate them from the cold and rain, of the winters here in British Columbia. Eagles vary in their feathers by age. Young eagles have more camouflauged markings than the white feathered heads of the adults, as below: Regards, Have you seen Norman s gallery lately? Check this one out in Thank You! (Haliaeetus leucocephalus), our national bird,is the only eagle unique to North America. The bald eagle's scientific name signifies a sea (halo) eagle (aeetos) with a white (leukos) head. At one time, the word bald meant white, not hairless. Bald eagles are found throughout most of North America, from Alaska and Canada to northern Mexico. About half of the world's 70,000 bald eagles live in Alaska. Combined with British Columbia's population of about 20,000, the northwest coast of North America is by far their greatest stronghold for bald eagles. They flourish here in part because of the salmon.
Dead or dying fish are an important food source for all bald eagles. Accipitridae family ; which also includes hawks, kites, and old-world vultures. Scientists loosely divide eagles into four groups based on their physical characteristics and behavior. The bald eagle is a sea or fish eagle. Color - Both male and female adult bald eagles have a blackish-brown back and breast; a white head, neck, and tail; yellow feet, legs and beak; and pale yellow eyes. Immature bald eagles have a mixture of brown and white feathers, with a black beak and brown eyes in younger birds; some immature bald eagles have more mottling than others. Adult plumage develops when a bald eagle become sexually mature; it takes five years for a bald eagle to attain solid white head and tail feathers. For the first five years they gradually change; the beak turns from black to yellow, the eyes from brown to pale yellow, body feathers from mottled to dark brown, and head and tail feathers from mottled to solid white. Some bald eagles have leucism, a genetic mutation that affects feather pigment. A leucistic bald eagle can have patches of white feathers on its body and wings; have overall faded or pale feathers; or have overall white feathers.
Examples: The bald eagle is the only eagle confined to North America. There are no other large blackish-brown birds with a white head and tail in North American. Skeleton - It weighs about half a pound (250 to 300 grams), and is only 5 or 6 percent of its total weight. The feathers weigh twice that much. Eagle bones are light, because they are hollow. The beak, talons, and feathers are made of keratin. Habitat - Bald eagles live along the coast and on major lakes and rivers where they feed mainly on fish. Longevity (life expectancy) - It's possible for bald eagles in the wild to live longer than thirty years, but the average lifespan is fifteen to twenty years. A captive eagle at West Stephentown, NY lived to be at least 48 years old. Heart rate - When we are checking our eagles at rest their heart rate is between 100-120 beats per minute. When we do their physical exams that rate jumps to 180-250 beats per minute. And when the birds are really stressed, like immediately after an exam involving beak coping talon trimming it may go as high as 300 beats per minute.
Keep in mind the heart rates at rest may be slightly lower for wild birds in better cardiovascular health and the high stress rates slightly higher in wild birds. (Heart rate information courtesy of Dr. Dan Hart. ) Status of the bald eagle - On June 28, 2007 the Department of Interior took the American bald eagle off the Federal List of Endangered and Threatened. Bald eagles will still be protected. The US Fish Wildlife Service Bald and Golden Eagle Post-De-listing. The number of nesting pairs in the lower 48 United States increased 10-fold, from less than 450 in the early 1960s, to more than 4,500 adult bald eagle nesting pairs in the 1990s. In the Southeast, for example, there were about 980 breeding pairs in 1993, up from about 400 in 1981. The largest concentrations were in the states of Florida and Louisiana. The most recent count of bald eagle nesting pairs in the lower 48 indicates MN, FL, and WI have the largest numbers. U. S. Fish Wildlife Service Estimated Number of Bald Eagle Breeding Pairs (estimates 9,789).
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