Eagles are large birds of prey which are members of the bird order Falconiformes and family Accipitridae, and belong to several genera which are not necessarily closely related to each other genetically. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species (the Bald and Golden Eagles) can be found in the USA and Canada, a few more in Central and South America, and three in Australia.

Eagles are differentiated from other birds of prey mainly by their larger size, more powerful build, and heavier head and bill. Even the smallest eagles, like the Booted Eagle (which is comparable in size to a Common Buzzard or Red-tailed Hawk), have relatively longer and more evenly broad wings, and more direct, faster flight. Most eagles are larger than any other raptors apart from the vultures.

Like all birds of prey, eagles have very large powerful hooked beaks for tearing flesh from their prey, strong legs, and powerful talons. They also have extremely keen eyesight to enable them to spot potential prey from a very long distance. This keen eyesight is primarily contributed by their extremely large pupils which cause minimal diffraction (scattering) of the incoming light.

In Britain before 1678, Eagle referred specifically to the Golden Eagle, the other native species, the White-tailed Eagle, being known as the Erne. The modern name "Golden Eagle" for Aquila chrysaetos was introduced by the naturalist John Ray.

Eagles build their nests, called eyries, in tall trees or on high cliffs. Many species lay two eggs, but the older, larger chick frequently kills its younger sibling once it has hatched.

Eagles are sometimes used in falconry. They appear prominently in myth and literature. In the Old World, such references are commonly to the Golden Eagle (or possibly closely related species found in warmer climates).

Major new research into eagle taxonomy suggests that the important genera Aquila and Hieraaetus are not composed of nearest relatives, and it is likely that a reclassification of these genera will soon take place, with some species being moved to Lophaetus or Ictinaetus.

• Bonelli's Eagle, the Booted Eagle and the Little Eagle have been moved from Hieraaetus to Aquila.
• Either the Greater Spotted Eagle and Lesser Spotted Eagle should move from Aquila to join the Long-crested Eagle in Lophaetus, or, perhaps better, all three of these species should move to Ictinaetus with the Black Eagle.
• The Steppe Eagle and Tawny Eagle, once thought to be conspecific, are not even each other's nearest relatives.

Species

FAMILY ACCIPITRIDAE

• Subfamily Buteoninae - hawks (buzzards), true eagles and sea-eagles
• Genus Geranoaetus
• Black-chested Buzzard-eagle, Geranoaetus melanoleucus
• Genus Harpyhaliaetus
• Crowned Solitary Eagle, Harpyhaliaetus coronatus
• Solitary Eagle, H. solitarius
• Genus Morphnus
• Crested Eagle, Morphnus guianensis