They have a long tail and pointed wings. Peregrines are slate gray or dark brown above and whitish below. Their crown and nape are black. Their dark back separates them from the similar, sandy-brown prairie falcon. They have been clocked at over 200 m.p.h. while diving after prey.
Peregrines begin reproducing when they are three years old.
They are monogamous and mate for life. Pairs perform elaborate aerial courtship displays at the start of the breeding season. Three to four eggs typically are laid, but nest failure is common, and juvenile mortality may be very high. Other birds are the primary prey of peregrine falcons. Peregrine falcons nest on high cliffs, often near water where prey species are most common.