A large falcon in which the sexes look alike.
Adults have a dark slate-blue back and wings and a dark blue tail that is lightly barred.
The top of the head is dark with a dark stripe running down the side of the face. The cere, legs, and feet are bright yellow. The underside of the adult is light with vertical streaks across the breast, belly and legs. Immatures are uniformly brown on the back, top of the head, and wings, with a light underside streaked with brown. Peregrine falcons are widely distributed resulting in many populations and sub-species each with a slight variation of the above plumage.