|Geographical Range||North America|
|Habitat||Woodlands, near freshwater|
|Scientific Name||Haliaeetus leucocephalus|
Symbol of Our Nation
The bald eagle was adopted as our national emblem in 1782. Our founding fathers chose it as a symbol of strength, long life and majestic looks, and also because it is the only eagle unique to North America. Legend also has it that, during a morning battle early in the American Revolutionary War, a group of bald eagles circled over the heads of the patriots as they fought.
The eagle appears in the Great Seal of the United States, in the seals of many of our individual states, and on most American coins.
A Bald-faced Lie
The bald eagle is not really bald. It carries that name because, when seen from a distance, its white head- and neck-feathers tend to make the bird appear bald.
This bird reaches an impressive size. From head to tail it can measure up to three-and-a-half-feet long, and weigh between eight and 15 pounds. The wingspan of an adult can reach eight feet.
Adult male and female bald eagles look the same, with the characteristic white head, white tail markings, and brown body. Their beak, feet and eyes are yellow. Young eagles are a mottled brown color. It takes juveniles four to five years to develop their adult plumage.
Bald eagles are strictly meat-eaters, and are efficient hunters. Their sharp claws (called talons) not only help them latch onto their prey, but often deliver a fatal blow. Then the birds use their beak to tear their food into bite-size pieces.
Their primary source of food is fish (often salmon) -- which can comprise 60 to 90 percent of their diet. (The eagles' preference for fish was unfortunately the cause of the birds' serious decline in the mid-20th century -- see "Conservation Success Story," below.) They also eat small birds, mammals (rabbits, muskrats), the occasional turtle, and carrion (animal carcass) if they come across it. Eagles have even been observed stealing fish from ospreys and other birds.
Eagles usually hunt by themselves. But in Alaska and the Pacific Northwest, large colonies of bald eagles gather along the rivers when the salmon are running. They perch in trees and on riverbanks, waiting to swoop down on tired and weakened fish.
Like most birds, bald eagles rely primarily on their keen sense of sight. Scientists have found their eyesight is six times sharper than that of humans.
Some eagles have been known to spot fish at distances up to one mile. No wonder someone with good eyesight is known as an "eagle eye!"
The Ultimate Sibling Rivalry
Bald eagles often mate for life. Courting behavior begins in early April, and often involves spectacular aerial displays in which the birds dive through the sky and sometimes lock their talons together.
After mating, the birds nest in the tops of tall trees, sometimes more than 100 feet above the ground. The male and female enlarge the nest every year with sticks, leaves, grasses, and feathers -- so much so that it can reach a massive size. The largest bald eagle nest on record was 20 feet deep, 10 feet wide, and two tons in weight!
The female usually lays two white eggs a day or two apart. Both parents take turns sitting on the clutch. When the chicks hatch, the stronger of the two babies often picks on the weaker one -- sometimes killing it, sometimes starving it to death by stealing its food.
A Southern "Vacation"
Adult bald eagles try to stay close to their nesting territory, as long as there is enough food and running water. But as winter sets in, many of them migrate south to the southern parts of North America and to Mexico. An eagle usually migrates to the same location every year, but returns in the spring to its original nesting grounds.
Eagles are able to migrate long distance because they make use of rising currents of warm air known as thermals. By gliding from thermal to thermal, they can soar for long periods of time with little need to flap their wings, thus conserving energy.
While bald eagles are solitary on their breeding grounds, they're more sociable during migration and during their winter "vacation." They can often be seen in large numbers roosting and hunting along rivers and streams.
Conservation Success Story
The eagle is one of America's best-known conservation successes, and its future now looks bright. But not so long ago the bald eagle was close to extinction.
A variety of factors caused the species' downfall. After World War II, there was widespread use of insecticides like DDT. These toxins drained into rivers from farmlands, accumulating in fish and other river animals. When the eagles ate the fish, the pesticides caused them to lay eggs whose shells were too thin to support the weight of brooding parents. The eagles' birth rate crashed.
Other trends worsened the situation. The eagles' habitat was severely reduced as farmers and developers drained swamps and other wetlands. Hunters, including ranchers intent on protecting their sheep, also took their toll. By 1963, there were only 417 known breeding pairs of bald eagles in the lower 48 states. In Missouri, all of the nesting bald eagles had disappeared. Eventually, the bird was declared endangered in 43 states and threatened in five others.
Then the tide turned. In 1967, the bald eagle was officially declared an endangered species (under a law that preceded the Endangered Species Act). A ban on DDT -- together with wetland restoration projects and bans on the hunting of bald eagles -- helped the birds make a slow comeback. By the mid-1990s, they had made such a significant recovery that the U.S. Fish and Wildlife Service upgraded their federal status in the lower 48 states to threatened. "IUCN" now lists the species as common.
Further recognition of the eagles' success was the recent announcement by federal officials that the bald eagle will soon be taken off the threatened species list. The birds will continue to be protected under the federal Bald Eagle Protection Act of 1940, which prohibits killing or selling the bird.
Bald eagles have begun to breed once again in Missouri -- home to the largest wintering population of the birds in the lower 48 states. Today, Missouri once again provides a summer home for nesting bald eagles and a wintering habitat for thousands more.
- A bald eagle can live up to 30 years in the wild, and longer in captivity.
- These eagles can fly up to 60 miles per hour, and can dive at speeds up to 100 miles per hour.
- All bald eagles in captivity -- including those at the Saint Louis Zoo -- can no longer survive in the wild. They have all been injured, often by human activities.