Of the accipiters, Cooper's Hawk is the most common breeder throughout the Lower 48. They were once thought to nest in forested areas only, but are common in suburban neighborhoods, parks, and golf courses nowadays (especially in the West). Cooper's Hawks are less common in southern Canada and virtually non-existent north of south-central Canada. Male Cooper's Hawks are about the size of a crow, but females are notably larger. They prey primarily on smaller birds, which they catch by surprise more than speed. In fact, they rarely chase birds for extended periods like falcons do, giving up chase once they've lost ground. Cooper's Hawks will also eat squirrels, especially Eastern females, which are quite powerful.
Cooper's Hawks from the West average smaller than than those in the East. Regardless, size can be extremely misleading when telling Cooper's from Sharp-shinned Hawk or Goshawk in flight. The fact is, it takes years of practice to gain the skill to accurately distinguish Sharp-shinned Hawks from Cooper's Hawks in the field. And even then, it's still impossible to ID every one. Cooper's Hawk are generally silent, but their call is a nasal "kek-kek-kek-kek-kek"; begging fledglings make a high-pitched, rising, whistled "sweeee."
Somewhat short wings, rounded at tips, and very long tail.
Rangy compared to the other accipiters, having proportionately longer, narrower wings, and longer tails.
Tail tip is rounded when closed, but squared if worn or damaged.
Larger-headed appearance; head of Cooper's Hawk projects further out from the wings than similar Sharp-shinned Hawk in all postures.
When perched, appear medium-sized, but tall, thin, and long tailed.
Steady fliers, adept at soaring and using powered flight.
Soar with wings held straight-out from the neck, often with a slight dihedral; glide on slightly bowed wings.
Stiff, powerful wing beats. Beware of the courtship display, which consists of slow, exaggerated, owl-like wing beats.
Two distinct age classes, adult and juvenile.
The eyes are yellow-green, turning yellow-orange by first spring, and eventually dark red in adulthood (some females keep orange eye).
Adult has rufous (on white) barring below, white undertail coverts. Blue-gray above with a blackish cap and a paler nape. Adult males typically more vibrant in color and more finely barred on the underparts, bluer upperwings, and gray cheeks (often rufous cheeks in first adult plumage).
Juvenile whitish-buff below with narrow, brown streaking, sometimes limited to breast and upper belly. Typically show least prominent streaking of the accipiters. Upperparts are brown to slate-brown with pale buff-rufous fringes on back and upperwing coverts, and contrasting tawny head.
Withdraws from the northern limits and migrates as far south as Central America.
Fairly common migrant at most hawk migration sites throughout the U.S.
The biggest fall flights occur along the East Coast and Kittatinny Mts., PA, and in the West at the Marin Headlands, CA, and Goshute Mts., NV from late September to early October.
Spring migration occurs mainly from mid-March to early May with significant flights along the southern shore of Lake Ontario, NY and the Wasatch Mts., UT.
(Map from Cornell Lab of Ornithology's All About Birds. For dynamic distribution maps, visit the eBird website.)