eagle, common name for large predatory birds of the family Falconidae (hawk family), found in all parts of the world. Eagles are similar to the buteos, or buzzard hawks, but are larger both in length and in wingspread (up to 71/2 ft/228 cm) and have beaks nearly as long as their heads. They are solitary birds, said to mate for life. The nest, or aerie, of twigs and sticks is built at a vantage point high in a tree or on a cliff in a permanent feeding territory and is added to year after year, the refuse of the previous nests decomposing beneath the new additions. Nests can become enormous, measuring up to ten feet across and weighing well over 1,000 pounds. The eaglets (usually two) do not develop adult markings until their third year, when they leave parental protection and seek their own mates and territories.

The American bald (in the sense of white, as in piebald), or white-headed, eagle (Haliaetus leucocephalus) is found in all parts of North America near water and feeds chiefly on dead fish (sometimes robbing the osprey's catch) and rodents. It is dark brown with white head, neck, and tail plumage. The northern species (found chiefly in Canada) is slightly larger than the southern, which ranges throughout the United States. With only 417 known breeding pairs in the 48 contiguous states in 1963, the bald eagle population was dwindling alarmingly; a decade later they were placed on the endangered species list. In one of the greatest success stories in species recovery, conservation methods such as the banning of DDT and the prohibition against eagle hunting had by the beginning of the 21st cent. increased the breeding population in the lower 48 states to some 5,000 pairs. In 1995 the bald eagle was removed from endangered status, and in 2007, when there were nearly 10,000 breeding pairs in the lower 48, it was removed from threatened status. The bald eagle (and golden eagle) continue to be protected by federal law.

The golden, or mountain, eagle (genus Aquila—whence aquiline, meaning eaglelike) is widespread in the Northern Hemisphere, in the United States found mostly in the West. Unlike the bald eagle, it is an aggressive predator. In Asia it is trained to hunt small game (see falconry). The adult is sooty brown with tawny head and neck feathers; unlike those of the bald eagle, its legs are feathered to the toes. The gray and Steller's sea eagles (also in the genus Haliaetus) are native to colder areas of the Northern Hemisphere; the king or imperial eagle to S Europe and Asia; and the rare monkey-eating eagle to the Philippines. The harpy, or harpy eagle (Thrasyaetus harpyia), of Central and South America, the largest (38 in./95 cm long) of the hawks, eats macaws and sloths. It was named for the winged monsters of Greek myth and was called "winged wolf" by the Aztecs. New Zealand's extinct Haast's eagle, which had a 10-ft (3-m) wingspan and weighed 30% to 40% more than the harpy, was the top predator in the archipelago's ecosystem prior to the arrival of humans.

Eagles—impressive both in size and for their fearsome beauty—have long been symbols of royal power and have appeared on coins, seals, flags, and standards since ancient times. The eagle was the emblem of one of the Ptolemies of Egypt and was borne on the standards of the Roman armies and of Napoleon's troops. The American bald eagle became the national emblem of the United States by act of Congress in 1782. In folklore the eagle's ability to carry off prey, including children (e.g., the legend of Ganymede), has been exaggerated; even the powerful golden eagle can lift no more than 8 lb (3.6 kg).

Eagles are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Falconiformes, family Accipitridae.

Red Eagle: see Weatherford, William.

Eagle Pass, city (1990 pop. 20,651), seat of Maverick co., W Tex., a port of entry on the Rio Grande opposite Piedras Negras, Mexico; inc. 1918. Linked by highway with Mexico City, it is a tourist center and a shipping and processing point for cattle, wheat, pecans, and oats. Mineral processing (especially oil and gas) and international trade are also important, but drug smuggling has been a problem in recent years. The site of a U.S. army camp during the Mexican War, it was on an important route to California during the gold rush. Fort Duncan (1849) was a base for actions against Mexicans and Native Americans, including the 1855 burning of Piedras Negras; it also housed U.S. troops during the Villa revolution in Mexico just before World War I.

Dark-brown eagle (Aquila chrysaetos) with golden, leaf-shaped nape feathers, dark eyes, gray beak, fully feathered legs, large yellow feet, and large talons. Its wingspread reaches almost 8 ft (2.3 m). It ranges from central Mexico (where it is the national bird) along the Pacific coast and through the Rocky Mountains to Alaska, and small numbers are found from Newfoundland to North Carolina. Also found in North Africa, it is more common across Russia, to southern China and Japan. It nests in cliff caves or in lone trees. The species is protected in the U.S.

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Any of many large, heavy-beaked, big-footed birds of prey belonging to the family Accipitridae, found worldwide. Eagles are generally larger and more powerful than hawks and may resemble a vulture in build and flight characteristics, but they have a fully feathered (often crested) head and strong feet equipped with great curved talons. Most species subsist mainly on live prey, which they generally capture on the ground. Eagles have been a symbol of war and imperial power since Babylonian times. They mate for life. They nest in inaccessible places and use the same nest each year. Species vary from 24 in. to 3.3 ft (60 cm–1 m) long. The sea eagles include the bald eagle. Seealso golden eagle.

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Species of sea eagle (Haliaeetus leucocephalus) that occurs inland along rivers and large lakes. Strikingly handsome, it is the only eagle native solely to North America, and it has been the U.S. national bird since 1782. The adult, about 40 in. (1 m) long with a wingspan of 6.5 ft (2 m), is dark brown with white head and tail and yellow beak, eyes, and feet. Bald eagles snatch fish at the water surface, rob osprey of fish, and eat carrion. They nest in lone trees, often on river islands. Though still protected in the U.S., the bald eagle is no longer considered an endangered species.

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