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Adult Cooper's Hawk
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Male
West East
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Female
West East
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Weight (avg)
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280 g 338 g
10 oz 12 oz
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473 g 566 g
16 oz 20 oz
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Male
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Female
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Length
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37 - 39 cm
14.6 - 15.4 in
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42 - 45 cm
16.5 - 17.7 in
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Wingspan
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62 - 90 cm
24.4 - 35.4 in
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75 - 90 cm
29.5 - 35.4 in
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Note that the western population tends to have smaller body mass than eastern. Both culmen and tarsus are slightly shorter in western birds also.
The adult male Cooper’s hawk has a steely blue-gray mantle and head. The forehead is lighter gray and the throat is still lighter, graduating to white. The chest is white with fine rufous bars extending down the thighs and across the under-wing secondary coverts. The upper-wing coverts are dark gray like the mantle. The primaries are barred with black; the under-wing primaries white with dark bars. The rectrices have four-five dark bands and a white tip. (One of the bands is normally obscured by the upper tail coverts.) The under-tail coverts are white. The bill is bluish-black and the cere is yellow-green. The feet and legs are yellow, and talons are black. The eyes are red and set close to the front of the head.
The female, in addition to being quite a bit larger than the male, has a lighter, brownish mantle and red-orange eyes. The barring on her chest, thighs, and under-wing secondaries is browner than the male’s, with only a slight rufous tint. The female often has a rufous-tinted cheek, while the male's is usually gray-white.
Age is a factor in eye color of both sexes, with the red color becoming more vivid over the years. Both adults and juveniles have a supraorbital ridge that gives the eyes a “menacing” appearance. A faint white superciliary line, or eyebrow, accents the ridge, reminiscent of the northern goshawk, although not nearly as prominent.
The juvenile hawk’s mantle is brownish-black, and the head is dark brown with rufous streaks. White patches can be seen in the scapulars and inner secondaries. The throat, chest, thighs, and under-wings are white, streaked with dark brown, becoming more indistinct at the thighs. The flanks and under-tail are white. Barring on the rectrices and wings is similar to the adult plumage. The tail is also tipped with white. The eyes are yellow. Flight feathers are slightly longer than those of the adult.
One of the features that distinguishes the adult Cooper’s hawk is the dark crown of the head, accentuated by lighter feathers at the nape and cheeks. The hawk frequently raises its hackles, giving the head a squarish appearance. The dark crown feathers tilting upward in back and settling low over the forehead gives the hawk an appearance of wearing a beret.
In flight, the Cooper’s hawk swoops low to the ground in a “flap, flap, flap, glide” motion. Using his tail as a rudder, he can maneuver upward, into the trees, and out of sight in seconds. When gliding, the hawk projects his head far beyond the “wrists.” While soaring the thermals, the hawk extends his head far ahead and the wings outward with a straight leading edge. This has earned him the nickname “flying cross.”
Next Chapter: History
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