Adult Peregrine falcons are dark gray to black above, darkest on side of the head. They have gray tips to their wing coverts and a rump pale gray finely barred with black. The nape often has rufous feather tips. Cheeks and underparts are white to pale rufous. The breast has black bars. Flight feathers and tail are slate-gray with narrow white bars below. They have a black bill with a pale gray base, eyes dark brown; cere, eye-ring and bare legs deep yellow. Sexes are similar in plumage, with the female about 10% larger than the male. Juveniles are sooty-brown above with rufous edges to their feathers. They are white to buff below with narrow pointed streaks. Their cere and eye-ring are blue-gray.