Adult: The plumage of adult peregrines is variable in both color and pattern. Most birds have a dark blue-gray dorsum, and light breast with variably dark barring. Distinctive dark “helmet” covers head to nape of neck, down side of face in dark malar stripes.
Juvenile: Dark brownish dorsum and “helmet,” light underparts are heavily streaked with brown. Males usually bluer on the back and tend to have less barring on the breast.
Pointed wings are 99 cm (39 in) long in males and 117 cm (46 in) in females. Total length of males averages 36-41 cm (14-16 in) and weight of males averages 0.45-0.68 kg (1.0-1.5 lb).
Females average 41-46 cm (16-18 in) in total length and weigh 0.72-0.95 kg (1.6-2.1 lb). Females are up to 33 percent longer than males. These birds have direct flapping flight and vertical “stoops” or plunges in pursuit of flying prey.
Several calls are used, with the most common being a constant “kak kak kak” given to intruders near the eyrie or when the bird is irritated.
During courtship, the nesting call is a whining wail that progresses into a prolonged “kaak kaak.” This nesting call is used by females to solicit food from the males (Glinski
Peregrine Falcon Viewing Areas