 | Bald Eagle
Haliaeetus leucocephalus  Fascinating Facts - The bald eagle was chosen as the national bird of the United States in 1782. Bald eagles are found only in North America, and are one of the seven species of sea eagles.
- Bald eagles are not bald. Adult eagles have white head feathers. The Latin name for the bald eagle means white-headed sea eagle.
- Eagles have 3-4 times better distance vision than humans and hearing that is comparable to a human’s. They have very little sense of smell.
- The bald eagle flies with deep strokes and soars on flattened wings. It may reach speeds of up to 44 miles per hour during migration and can dive at 200 miles per hour. Eagles strike their prey with enormous force; a bald eagle can hit with twice the force of a rifle bullet.
- Female bald eagles are larger than males.
Physical Characteristics The bald eagle is a large bird of prey, or raptor, with a wingspan measuring about six feet. Its average weight, however, is only about nine pounds - two pounds less than the average house cat. Its larger bones are hollow, and the bird has a lot of feathers, making it appear bigger than it really is. As a result, the bald eagle usually takes fairly small prey, light enough to be carried into a tree for undisturbed eating.
Adult bald eagles have white heads and tails, and dark brown body and wing feathers. The young are mostly mottled brown and white. The plumage is the same in both sexes. Eagles' beaks, eyes, and feet are yellow. Eagle beaks are sharp and powerful, and they have strong, grasping, taloned feet, which have small bumps on the bottoms of the toes to help the bird hold on to the slippery scales of a fish. Female are larger than males. This is true in most diurnal species of raptors.
Vision is the bird's most important sense, and eagle eyes are exceptionally powerful. Their large pale eyes see in color and can detect objects three to four times further away than humans. Eagles can rotate their heads up to 270 degrees which allows excellent monocular and binocular vision. Their hearing capabilities are about the same as humans. Their sense of smell is poor, but their taste is acute.
The call of an eagle is a loud, high-pitched scream, similar to a gull, but broken into a series of notes in rapid succession. The voice has been called unbecoming for a bird of its size and strength.
Life span is 20-30 years in the wild (only about 50% survive their first year), and up to 50 years in captivity. Habitat/Diet Bald eagles are able to live anywhere with adequate nest trees, roosts and feeding grounds, and are found in North America, Alaska, Canada, and the western coast of the United States.
Bald eagles are diurnal (daytime) hunters. They hunt by swooping low over rivers, streams and lakes, using their powerful talons to grasp fish that are swimming close to the surface. Bald eagles will occasionally steal food from other predators, and they will also eat carrion if other food is scarce. Bald eagles hunt alone or in numbers on the banks of streams, wading in the water to catch the exhausted fish and then eating them on the bank - often right next to brown bears doing the same thing. Eagles do not chew their food, but tear it into manageable portions and swallow. Swallowed food is stored in the crop - a pouched enlargement of the gullet that serves as a receptacle for food - and later goes into the digestive system. This allows the eagle to gorge itself at each kill.
In the wild, bald eagles eat fish and to a lesser degree, birds and medium-sized mammals, with some carrion, reptiles and amphibians. At the Zoo, the bald eagles are fed a diet of rats, herring, mice and rabbits. Social Behavior Bald eagles mate for life, and adult coloration signals sexual maturity. They have an aerobatic courtship ritual considered the most beautiful of any raptor. Nests are usually found in tall trees or on cliffs and are made of branches and sticks and meticulously intertwined into a basket by the female. Clutches range from one to three eggs. Incubation is usually 35 days. Both sexes incubate the eggs, but the female generally does most of the work. Status In The Wild In the early part of the century, hunting eagles was a popular sport. Bald eagles were shot not only for their feathers, but because farmers thought they posed a threat to livestock and hampered the fishing industry. In more recent years, pollution greatly reduced their numbers. Pesticide runoff accumulates in fish, and the chemicals then accumulate in the eagles’ bodies. DDT in a female bald eagle’s body disturbs the eggshell-making process, causing her to produce very weak shells or no shells at all. Bald eagles once numbered 50,000 in the United States, but by the time the U.S. restricted the use of DDT in 1972, only 800 breeding pairs remained. Under the Endangered Species Act of 1973, the bald eagles have made a steady recovery and breeding pairs now number around 3,000. By July 1995, the bald eagle had been downgraded from “endangered” to “threatened,” and in 2007, the U.S. Department of the Interior took the bald eagle off of the Endangered Species List. Laws like the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act still prohibit the hunting or sale of eagles or eagle parts; it is illegal for anyone to collect eagle parts (even feathers) without a permit. For some Native American groups, the possession of eagle feathers is allowed, since these feathers are often used in traditional ceremonies. Other For over twenty years, the San Francisco Zoo has helped to conserve bald eagles, maintaining the largest captive breeding and release program in the country. Even though the species is not officially endangered any longer, the Zoo’s off-exhibit captive breeding facility for bald eagles is still home to two pairs of bald eagles. Since 1991, the Bald Eagle Recovery Program, in conjunction with the Wildlife Institute, has released over 95 eagles to sites in central and southern California, as well as Tennessee. The Zoo initiated its California Bald Eagle Breeding Program in 1985 to help with the recovery of the state's bald eagle breeding population, which had declined from a historic high of approximately 400 pairs to fewer than 35 pairs in the 1970’s. Live Eagle Nest Cam! During breeding season, you can watch the Catalina Island eagles at the West End nest via live webcam! Visit www.iws.org and select "Eagle Nest Cam" from "Interactive" on the menu. The Bald Eagle Recovery Program is headquartered at the Zoo's off-exhibit facility, the Avian Conservation Center. San Francisco Zoo houses three rescued eagles, injured in the wild and incapable of being re-released. You might see one of our rescued bald eagles on Eagle Island near the bear exhibits, or meet one of our eagle ambassadors at a special event, or on a walk through the Zoo with a handler. |
