eagle

   The bald eagle (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.

   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.

   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.)

Bald eagle, Image created by Hope Rutledge

   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.
   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.
   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.

Bald eagle, Image created by Hope Rutledge

   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.

Bald eagle, Image created by Hope Rutledge

   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.

American Eagle: A Visual History of Our National Emblem

American Eagle: A Visual History of Our National Emblem By Preston Cook
Available wherever books are sold.
To have the book signed by the author: Please order the book through the National Eagle Center here.
Sales of the book through the National Eagle Center will support the development of the museum.

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