Eagle
The bald eagle (Haliaeetus leucocephalus), our national bird, is the only eagle unique to North America. The bald eagle's scientific namesignifies 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. Eagles are a member of the 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. There are two subspecies of bald eagles. The "southern" bald eagle, Haliaeetus leucocephalus leucocephalus, is found in the Gulf States from Texas and Baja California across to South Carolina and Florida, south of 40 degrees north latitude. The "northern" bald eagle, Haliaeetus leucocephalus alascanus, is found north of 40 degrees north latitude across the entire continent. The largest numbers of northern bald eagles are in the Northwest, especially in Alaska. The "northern" bald eagle is slightly larger than the "southern" bald eagle. Studies have shown that "northern" bald eagles fly into the southern states and Mexico, and the "southern" bald eagles fly north into Canada. Because of these finding, the subspecies of "northern" and "southern" bald eagles has been discontinued in recent literature. Color - Both male and female adult bald eagles have a blackish-brown back and breast; a white head, neck, and tail; and yellow feet and beak. Juvenile bald eagles are a mixture of brown and white; with a black beak in young birds. The adult plumage develops when they are sexually mature. It takes about five years for their head and tail feathers to gradually turn white. 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. Size - A female bald eagle's body length varies from 35 to 37 inches; with a wingspan of 79 to 90 inches. The smaller male bald eagle has a body length of 30 to 34 inches; with a wingspan ranging from 72 to 85 inches. An eagle's average weight is ten to fourteen pounds. Northern birds are significantly larger than their southern relatives. Eagles sit at the top of the food chain, making them more vulnerable to toxic chemicals in the environment, since each link in the food chain tends to concentrate chemicals from the lower link. A bald eagle's lifting power is about 4 pounds. They do not generally feed on chickens or other domestic livestock, but they will make use ofavailable food sources. Bald eagles will take advantage of carrion (dead and decaying flesh). Because of its scavenger image, some people dislike the bald eagle. Other people do not care for powerful and aggressive birds. Still other people object merely on the grounds that it is a bird of prey, which kills other animals for food. |
| Voice - Shrill, high pitched, and twittering are common descriptions used for bald eagle vocalizations. Eagles do not have vocal cords. Sound is produced in the syrinx, a bony chamber located where the trachea divides to go to the lungs. Bald eagle calls may be a way of reinforcing the bond between the male and female, and to warn other eagles and predators that an area is defended. Bald eagle audio. Eyesight - An eagle's eye is almost as large as a human's, but its sharpness is at least four times that of a person with perfect vision. |
| 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. eagle skeleton 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. Body Temperature - About 106 degrees Fahrenheit (41 degrees Celsius) Eagles do not sweat, so they need to use other cooling methods such as perching in the shade, panting, and holding their wings away from their body. Tolerance to cold temperatures - A bald eagle's skin is protected by feathers lined with down. Their feet are cold resistance, consisting of mostly tendon. The outside of the bill is mostly nonliving material, with little blood supply. |
 Immature bald eagle |
Golden eagles are larger than bald eagles in average height and wingspan, but there isn't much difference in average weight. One way to distinguish a golden eagle from an immature bald eagle is leg plumage. A golden eagle's legs are entirely feather covered; an immature bald eagle's lower legs are bare. As seen while in flight, juvenile golden eagles have white patches at the base of the primaries; the tail is white with a distinct dark terminal band. It takes four years to acquire adult plumage. Adult golden eagles are brown with tawny on the back of the head and neck; tail faintly banded. |