The American Bald Eagle.....general infoSource...
http://www.baldeagleinfo.com (Haliaeetus leucocephalus),
the bald eagle's scientific name
signifies a sea (halo)
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 of available 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. 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. 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. Beak
- The hook at the tip is used for tearing. Behind the hook, the upper mandible, the edge sharp enough to slice tough skin, over laps the lower, creating a scissors effect. A bald eagle's beak is a strong weapon, but is also delicate enough to groom a mate's feathers
or feed a small portion of food to a newly hatched chick
. The beak of a female eagle is deeper (distance from top to chin) than the beak of a male. The beak and talons grow continuously, because they are made of keratin, the same substance as our hair and fingernails. The beak of a captive eagle is not warn down naturally, so must be trimmed annually. Talons
- Talons are important tools for hunting and defense. Eagles kill their prey by penetrating its flesh with their talons.
Eagles can open and close their talons at will. If an eagle is dragged into the water by a fish too large for the eagle to lift, it is because the eagle refuses to release it. In some cases this is due to hunger
To help them soar, eagles use thermals which are rising currents of warm air and up-drafts generated by terrain such as valley edges or mountain slopes. Soaring is accomplished with very little wing-flapping, enabling them to conserve energy. Long-distance migration flights are accomplished by climbing high in a thermal, then gliding downward to catch the next thermal where the process is repeated. Several eagles soaring in a thermal together is described as a "kettle of eagles."
Bald eagles can fly to an altitude of 10,000 feet. During level flight, a bald eagle can achieve speeds of about 30 to 35 mph. The tail
- is very important for flight and maneuvering. While the bald eagle is soaring or gliding in flight, the tail feathers
are spread in order to attain the largest surface area and increase the effect of thermals and up-drafts. The tail also helps to brake the eagle when landing and assists in stabilization during a controlled dive or swoop toward prey. The strength of the feathers and the follicles holding the feathers is quite impressive while watching the tail move back and forth and up and down during maneuvers.