Eagle is a common name for many large birds of prey of the family Accipitridae. Most of the sixty species of eagles are from Eurasia and Africa. Outside this area, just fourteen species can be found – two in North America, nine in Central and South America, and three in Australia.
Eagles are different from many other birds of prey mainly by their larger size, more powerful build, and heavier head and beak. Most eagles are larger than any other raptors apart from vultures. Eagles eyes are very large in proportion to their heads and have extremely large pupils, with a million light-sensitive cells per square mm of retina, five times more that a human’s 200,000. While humans see just three basic colours, eagles see five. These adaptations gives eagles extremely keen eyesight and enable them to spot even well-camouflaged potential prey from a very long distance. In fact the eagles’ vision is among the sharpest of any animal and studies suggest that some eagles can spot an animal the size of a rabbit up to two miles away.
Many eagle species lay two eggs, but the older, larger chick frequently kills its younger sibling once it has hatched. Adults do not intervene. Some eagles are built with short wings and long tails enabling them to hunt in the tight confines of a forest, while others are have short tails and broad long wings allowing them to soar high above open plains and water.
The Harpy Eagle and the Philippine Eagle have wings that spread 2.5m across and use their massive, sharp talons, to kill and carry off prey as large as deer and monkeys. Although most eagles are carnivorous the African Vulturine Fish-Eagle is primarily a vegetarian, feeding on rich oil palm fruits. In Greece, Golden Eagles eat turtles, dropping them from great heights onto rocks to break open their armoured shells. In the Lord of the Rings by Tolkien, Golden Eagles came to the rescue of the hobbits on several occasions. Golden eagles in Wyoming have been observed foraging areas that cover 100 square miles. To defend their territories and attract a mate, bald eagles put on spectacular aerial displays including death-defying swoops and seemingly suicidal dogfights that involve locking talons with another bird and free-falling in a spiral.
Although many eagle populations are dwindling as a result of habitat destruction, hunting, and pollution, conservation efforts are helping some species such as the Bald Eagle, which has made a dramatic comeback in the U.S. over the last few decades.