- Photo: Ned Harris
Both adults participate in the nest building with the male bringing in most of the dead sticks and the female shaping the nest
Gray Hawks are medium sized buteos that reach their northernmost distribution in the southwest United States (primarily in Arizona and New Mexico). They are summer residents in southeastern Arizona. Pairs are known to have nested within a very few miles of Sabino Canyon. I have observed them nesting as far north as Aravaipa Canyon. In 1998 it was estimated that there were approximately 80 nesting pairs in Arizona. My own observations have convinced me that their population has increased since then.
They are intermediate in shape between buteos (e.g. Red-tailed Hawks) and accipiters (e.g. Cooper’s Hawks) with a longer tail, shorter and rounded wings and longer legs than other buteo species. Flight is similar to that of an accipiter with rapid wingbeats followed by a shorter glide. Females are distinctly larger than males. Adults heads and upperparts are medium gray with their underparts finely barred with gray and white throughout. The cere, legs and feet are yellow. Adults have a boldly banded black and white tail. Juveniles have brown backs with heavily spotted or streaked white underparts.
Pairs form as soon as the adults reach their breeding territories in late March. The stick nest is frequently located in a large cottonwood often concealed by foliage. Both adults participate in the nest building with the male bringing in most of the dead sticks and the female shaping the nest. Two to three eggs are laid typically in early May with an incubation period of approximately 33 days. Only the female incubates. The young remain in the nest for about 6 weeks and then fledge within the first 2 weeks of July. Adult plumage is typically reached in April through August beginning in the second calendar year. Gray Hawks typically remain in their natal area until late September or early October and then depart to spend the winter in Mexico. The adults return in mid to late March and I have viewed their northbound migration for each of the last 4 years from the Hawkwatch in Tubac. The one-year old birds return later and typically arrive during the first few weeks of May. They return to their natal areas and are soon driven away by the adults and go off and find their own new territories.
Gray Hawks are “perch-and-pounce” hunters. They typically perch on a low branch and look for prey. Their diet consists primarily of whiptail and spiny lizards augmented by occasional small birds and small mammals.
Additional Photo: Pair of adult Gray Hawks. Note how much larger the female is and what a mighty hunter the male is.