The peregrine falcon is a raptor, or bird of prey.

Adults have blue-gray wings, dark brown backs, a buff colored underside with brown spots, and white faces with a black tear stripe on their cheeks. They have a hooked beaks and strong talons. Their name comes from the Latin word peregrinus, which means "to wander." Peregrines are the fastest animals on the planet – they are able to dive at 200 miles per hour.

Historically, the use of DDT (Dichloro-diphenyl-trichloroethane) as a pesticide resulted in a rapid decline in the population. DDT and DDE (a breakdown product of DDT) cause eggshell thinning, resulting in the eggshell breaking while being incubated.

Since the ban on DDT in the 1970's, peregrine falcon populations have recovered significantly, and are even showing signs of recovery in areas in which they haven't been spotted in some years. Once listed as endangered under the Endangered Species Act, the peregrine falcon was delisted in 1999.