Cooper's Hawk Identification: Size, Eyes, Tail, Look-alikes

• Head pattern: Adult: shows a more pronounced dark cap than Sharp-shinned Hawk
• Body pattern: Adult: blue-gray above, pale reddish below; juvenile brown above, streaked below
• Tail: Tail tip is more rounded (though hard to judge) and often shows a wider white terminal band than Sharp-shinned Hawk
• Size compared with look-alikes: Larger than the visually similar Sharp-shinned Hawk, with a relatively bigger head, longer tail, and thicker legs
• Size: Female 17-18 in; Male 15-16 in; about the size of a Crow

Cooper's Hawk is larger with a relatively bigger head, longer tail, and thicker legs than Sharp-shinned Hawk, and its tail tip is more rounded with a wider white terminal band, versus the Sharp-shinned's squared-off tail tip The Sharp-shinned Hawk page lists its own marks.

Mature forest, open woodlands, wood edges, and river groves; increasingly found in suburbs and cities with tall trees for nest sites Found all year across much of its range in the US and southern Canada; northernmost breeders migrate south for winter

Raptors are usually far away and against the sky, so expose for the bird, not the sky, and take several frames as it turns: the tail shape, wing shape and underwing pattern show best in flight. For a perched bird, get the head and chest in one frame. Size is hard to judge alone; compare with a nearby crow, gull or fence post. The app names the likely species; confirm with the marks above.

HawkWatch International gives the Cooper's Hawk a length of 14-19 inches and a wingspan of 28-34 inches. The shape is the thing to learn: somewhat short wings, rounded at the tips, and a very long tail. The head is large and projects further beyond the wings in flight than a Sharp-shinned Hawk's does. The tail looks rounded when closed, though a worn tail can look square.

In flight it is a steady flier with stiff, powerful wingbeats. It soars with the wings held straight out and glides on slightly bowed wings.

HawkWatch describes the eye changing with age: yellow-green in young birds, yellow-orange by the first spring, and eventually dark red in adults. Plumage changes with it. Adults are blue-gray above with a blackish cap and a paler nape, barred rufous on white below, with white undertail coverts. Juveniles are whitish-buff below with narrow brown streaks, and HawkWatch notes they typically show the least prominent streaking of the accipiters.

A close photo of the eye is therefore a quick age check: a red-eyed, gray-backed bird is an adult; a yellow-eyed, brown, streaked one is in its first year.

The two birds most often confused with a Cooper's Hawk are its relatives the Sharp-shinned Hawk, which is smaller, and the Northern Goshawk, which is larger. HawkWatch separates all three mainly by head projection and body proportions, and is candid that reliable separation in the field takes years of practice.

The name has changed too. Audubon and HawkWatch now list the Cooper's Hawk as Astur cooperii; older field guides, and the scientific-name field on this page, use Accipiter cooperii. It is the same bird.

It is hunting. Audubon says the Cooper's Hawk feeds mainly on medium-sized birds in the size range of robins, jays and flickers, and also on small mammals such as chipmunks, tree squirrels, ground squirrels, mice and bats. It hunts by stealth, moving from perch to perch in dense cover, or cruising low and coming in from behind shrubbery to take prey by surprise. A yard with a busy feeder and nearby shrubs suits that style.

It nests in trees, usually 25-50 feet up. Audubon gives a clutch of 3-5 pale bluish-white eggs, sometimes 1-7, incubated for usually 34-36 days; the young can fly at about 4-5 weeks.