 | ||||||
| ||||||
The Eagle
Eagle is the name of some of the largest and most powerful birds in the world. Among birds of prey, only condors and some species of vultures are larger than eagles. Eagles look fierce and proud, and they sometimes soar gracefully high in the air. They are often pictured as courageous hunters and have long been symbols of freedom and power. The golden eagle best fits this description and is sometimes called "king of birds." But eagles are not always as bold and fierce as they look. Most will eat whatever flesh is easiest to get, including carrion (dead animals).
Eagles are careful to avoid danger. They usually stay away from human beings and rarely attack except when cornered. A few species of eagles also may attack when defending their nests and young. An eagle's chief weapons are its powerful legs, feet, and talons (claws). Some eagles also bite in self-defense. Eagles may attack newborn lambs or other livestock, but they do so only rarely.
Roman warriors used a golden figure of an eagle as a sign of strength and bravery. Russian and Austrian emperors also used eagles as symbols. The United States chose the bald eagle as its national bird in 1782.
The body of an eagle
Eagles vary in size, depending on the species and the individual. Females are generally larger than males. Wingspreads of different species and individuals range from about 4 to 8 feet (1.2 to 2.4 meters). Most eagles weigh about 7 to 12 pounds (3.2 to 5.4 kilograms), but some weigh as much as 20 pounds (9.1 kilograms).
If the wind and other flying conditions are favorable, some species of eagles may be able to carry prey weighing nearly as much as themselves. Normally, however, eagles can only carry smaller prey.
The head of an eagle is large and covered with feathers. An eagle has large eyes that are located on the sides of its head. However, it can see straight ahead. Most birds have keener sight than humans and other animals, but eagles and hawks are said to have the keenest sight of all. Eagles can probably sight their prey while soaring high in the air. But they usually watch from perches or fly close to the ground while they are hunting. Eagles have large, strong, hooked beaks, which they use to tear up their prey. The golden eagle's beak measures about 2 inches (5 centimeters) long and 1 inch (2.5 centimeters) from top to bottom. The bald eagle's beak is even larger.
Feet and legs. Eagles have strong legs and feet. Most eagles have scaly, bright yellow skin on their feet. Eagles seize and kill prey with their long, curved talons. They also use their talons to carry prey to a feeding place. When eagles fight, they dive at each other and try to strike with their talons. The legs of golden eagles and several other species are covered with feathers. The lower part of the bald eagle's legs is bare.
Feathers and wings. Eagles have such long, broad wings and tails that they look clumsy when they are on the ground. But the wings easily support their heavy bodies when they fly. Eagles can glide great distances without flapping their wings. The long feathers in their wings are strong and stiff, and they are shaped so the air flows smoothly over the surface of the wing. When the eagle soars, the feathers spread out like fingers and bend up at the tips.
Most adult eagles are dark brown or black, but many have white areas. Young eagles do not have feathers that match those of their parents until about 4 years of age.
The life of an eagle
Wild eagles that survive to adulthood are thought to live from 20 to 30 years. In captivity, eagles may live 50 years or more. Most young eagles first breed when they are about 5 years old. Mated eagles are thought to stay together. If one member of a pair dies, the other may find another mate. In winter, bald eagles may gather in areas with plentiful food. But during the breeding season, each pair claims a territory around its nest and keeps other eagles away. The golden eagle may defend a territory of about 20 to 60 square miles (50 to 160 square kilometers). The bald eagle holds a smaller territory.
Nests of eagles are called aeries or eyries «AIR eez or IHR eez». Bald eagles usually build their aeries in the tops of tall trees that are near water. Some nest on cliffs. Golden eagles usually nest on high cliffs in the mountains. Some eagles in Asia nest on the ground. Eagles tend to use the same aerie every year. However, some eagles have two or more aeries. They use one aerie one year and another the next year.
Eagles build aeries mainly with sticks. They often decorate the aerie with fresh leaves while they are using it. They usually add new material each year they use an aerie, so many old aeries are very big. A new aerie may be 6 feet (1.8 meters) across and 18 inches (46 centimeters) deep. But an old aerie may be up to 10 feet (3 meters) across and 15 feet (4.5 meters) deep.
Eggs are about 3 inches (7.6 centimeters) long and 2 inches (5 centimeters) across. Females lay one, two, or—rarely—three eggs each year. The eggs of golden eagles are white or spotted with reddish-brown or gray. Those of bald eagles are white and become stained with yellow in the nest. Northern eagles lay eggs in March. Bald eagles in Florida lay eggs during the fall and winter.
The eggs hatch in five to six weeks or more, depending on the species. During that time, the female incubates the eggs—that is, she sits on them to keep them warm. The male incubates them occasionally, and brings food to the female while she sits. After the eggs hatch, both parents guard the nest and take food to the young.
Young eagles are called eaglets or eyasses. Eaglets are hatched with their eyes open. They are covered with a grayish-white down (fuzz). Their regular feathers begin to grow when they are 2 to 3 weeks old. Eaglets are not able to tear up their own food until they are 6 or 8 weeks old. They leave the nest when they are 11 to 12 weeks old, but they cannot fly very well at first. They stay near the aerie for several weeks. The parents feed them for a few more months until they can hunt well enough to get their own food.
Some species of eagles hatch two eggs. But it is unusual for both eaglets to survive. One usually hatches two or three days before the other. The older eaglet is larger and takes more than its share of food. It also attacks the smaller eaglet repeatedly and may kill it.
Food. Eagles hunt only during the day. They spend the night in their aeries or on a safe perch. Often, two eagles hunt together. Some eagles eat only certain types of prey. But most hunt a wide variety of prey and occasionally eat carrion or steal prey from other animals.
The golden eagle eats rabbits, hares, ground squirrels, and birds. Sometimes it eats young deer and lambs, and it may also eat carrion. The golden eagle usually flies low over open hillsides, dropping down quickly to seize its startled prey.
The bald eagle eats mainly fish. It finds schools of fish by following other fish-eating birds. It snatches fish from the water while flying. A bald eagle can swim to shore with its catch by floating and using a rowing motion with its wings. It sometimes takes fish away from other birds, such as gulls and ospreys. Occasionally, bald eagles catch coots and other water birds by hovering over them and forcing them to dive repeatedly until they are exhausted. In addition, they sometimes catch birds in the air with spectacular aerial maneuvering. Bald eagles also capture mammals and sometimes eat carrion.
Kinds of eagles
There are about 60 species of eagles. Most of these species are native to tropical regions, particularly in Africa and Asia. Only two species, the bald eagle and golden eagle, are native to the continental United States and Canada.
The bald eagle is not really bald. Its head is covered with white feathers. Its tail is also white. A young bald eagle is dark brown and has scattered light markings. The bald eagle is found only in North America and is the national bird of the United States.
Until the mid-1900's, hunters and trappers killed many bald eagles. The species has been protected by federal law since 1940 in the lower 48 states and since 1953 in Alaska. However, the continued loss of wilderness regions to agriculture and urban development caused a further decline in bald eagle populations. The number of bald eagles also dropped because of the pollution of lakes and rivers with pesticides and industrial wastes. Some of these pollutants built up in the bodies of fish that the eagles ate. In most cases, the pollutants did not kill the birds, but they interfered with the birds' ability to reproduce. By the mid-1970's, there were only about 2,000 to 3,000 bald eagles nesting in the lower 48 states.
Bald eagle
Since then, however, the bald eagle has made a gradual comeback. The United States government has banned certain pesticides and tightened controls on other pollutants. Conservation groups have restocked former nesting areas with young eagles. Bald eagles also have become more accustomed to people and now often nest in nonwilderness areas close to human activity. Today, there are about 20,000 bald eagles in the lower 48 states. About 85,000 bald eagles are estimated to live in Canada and Alaska.
Eagles come in all shapes and sizes, but you will recognize them chiefly by their attitudes.
Charles Prestwich Scott
The Bateleur eagle of Africa hunts over a territory of 250 square miles a day.
