Male Cooper's Hawks are dark gray on the back with a black crown and paler neck and face. The belly is white with distinct horizontal rufous bars extending from the neck to the tail and legs. The iris of the eye is deep red and the feet are yellow. Adult females have similar markings, except they have more brown on the back and the eye color is paler. Juveniles are brown on the back with some white streaking on the belly, and the tail has a white tip and three or four dark brown bars. Cooper's Hawks measure from 14 to 20 inches in length with wingspans of 27 to 36 inches. Females are somewhat larger than males. A medium-size diurnal raptor with rounded wings, a long brown/black banded tail (often rounded at the end), and a hooked bill; adult is mainly gray/brown above, barred rusty brown below, with strong contrast between dark crown and paler nape and back; immature is paler, with brown upperparts, dark-streaked whitish or buffy underparts, and white undertail coverts. Average length 36 to 51 centimeters, wingspan 74 to 94 centimeters; females average larger than males.
For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.
Appearance is similar to that of the Northern Goshawk and the Sharp-shinned Hawk. Differs from Sharp-shinned Hawk (Accipiter striatus) by larger size; longer, more rounded tail that has a wider white terminal band; larger head; and (in adult) stronger contrast between the dark crown and paler nape and back. Differs from Northern Goshawk (Accipiter gentilis) in smaller size (average length 36 to 51 cm vs. 53 to 66 cm); lack of conspicuous pale eyebrow; less conspicuous white undertail coverts; broader white tip on tail; and proportionately longer tail and shorter wings.
Western Hemisphere Range
Bozeman migration: April 15 to May 10 and September 10 to October 1; no peaks (Skaar 1969). Statewide peaks: April 21 to 30 and late August to early September (Davis 1961).
They nest in dense deciduous and coniferous forest cover, often in draws or riparian areas. They hunt in these areas or in adjacent open country. In the Bozeman area, winter birds occur in forests and thickets of valley. In summer, they are confined to the forest edge in the foothills (Skaar 1969).
Small to medium-sized birds comprise most of the diet of Cooper's Hawks, although they also eat small mammals.
Numbers are decreasing in the Fortine area. Numbers were described as the most common hawk in SW MT before turn of century. This is not true today (Skaar 1969).
Cooper's Hawks arrive at their nesting territories in late March and early April. Clutches of three to five eggs are usually laid by mid-May. They hatch after an incubation of 30 to 34 days. The young fly about 30 days after hatching and remain in the vicinity of the nest for up to three weeks after leaving it. Flying young seen August 2 near Fortine. Dates are probably somewhat later than those reported in northern Utah: nestlings found by June 19 and fledged young by July 30 (Johnsgard 1986).