Peregrine Falcon
Falco peregrinus

Also called DUCK HAWK , bird of prey of the family Falconidae, which occurs worldwide but has become rare throughout almost all of its range. Bluish gray above with underparts white to yellowish with black barring, peregrines range from about 33 to 48 centimetres (13 to 19 inches) long. They are strong and fast. They fly high and dive at tremendous speeds, striking with clenched talons and killing by impact. The prey includes ducks and shorebirds. Peregrines inhabit rocky open country near water where birds are plentiful. The usual nest is a mere scrape on a ledge, high on a cliff. The clutch is two to four reddish brown eggs. The young fledge in five or six weeks. The chief cause of the peregrine falcon's decline has been the buildup of chlorinated hydrocarbons (which are used in such pesticides as Ddt) in the bird's food sources. The chemicals become concentrated in the peregrine's tissues and interfere with reproduction, particularly by causing the thinning of eggshells and the resultant loss of eggs. Habitat destruction has also played a role in the falcon's population decline. The American peregrine falcon (F. p. anatum), which once bred from Hudson Bay to the southern United States, is listed as endangered in the Red Data Book. It is extinct in the eastern United States and eastern boreal Canada. The Alaskan peregrine is also classified as endangered, and several other subspecies worldwide are listed as threatened or vulnerable. Peregrine falcons can be bred in captivity, and programs have been instituted to release captive-bred peregrines into areas where the bird has become extinct. The ultimate success of such programs, however, may depend on the elimination of chlorinated hydrocarbons from the peregrine falcon's food chain.

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