Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species are found in Eurasia and Africa.
Outside this area, just two species (the Bald and Golden Eagles) can be found in the United States and Canada, nine more in Central and South America, and three in Australia.
Eagles differ from many other birds of prey mainly by their larger size, more powerful build, and heavier head and beak. 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.
Like all birds of prey, eagles have very large hooked beaks for tearing flesh from their prey, strong muscular legs, and powerful talons
They also have extremely keen eyesight which enables them to spot potential prey from a very long distance.
This keen eyesight is primarily contributed by their extremely large pupils which ensure minimal diffraction (scattering) of the incoming light.
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.
The dominant chick tends to be the female, as they are bigger than the male. The parents take no action to stop the killing.
The modern English name of the bird is derived from the Latin term aquila by way of the French aigle.
The Latin aquila may derive from the word aquilus, meaning dark-colored, swarthy, or blackish, as a description of the eagle’s plumage; or from aquilo, the Latin version of Greek boreas, or north wind; however, aquilus and aquilo may just as well derive from aquila (or be unrelated) and the latter be of unknown origin.