College of Veterinary Medicine |

Healthy Animals, Healthy People, Healthy Planet


Riley is a male Cooper's Hawk (Accipiter cooperii) who came to the WSU Veterinary Teaching Hospital in the summer of 2008.  He was found in Pullman unable to fly due to his permanently injured left wing.  The cause and nature of the damage to his wing is unknown, and because of it, he is non-releasable. Riley was young when he came in – most likely under one year of age.
Cooper’s Hawks are dark steel grey above, and streaked reddish-brown and tan on the underside. They have thick dark bands down the tail, and the tip of the tail is white. When fanned out, the end of the tail curves, making a “C” shape. This helps to distinguish it from the very similar Sharp-shinned Hawk, which has a straight or “sharp” edge to its tail. Both of these hawks, along with the Goshawk, are members of the genus Accipiter of hawks (as opposed to the genus Buteo). The Accipiters have shorter, broader wings and long, rudder-like tails – both adaptations that allow them to steer swiftly between trees in flight. The adults of all three species also have blood-red eyes. 
Cooper’s Hawks are found all over North America, from Canada to Mexico. They are native to dense forests, but have also adapted to living in the suburbs, where they often find unsuspecting prey around bird feeders. They build nests out of sticks and other vegetation in the crook of a tree, usually at least 25 feet above the ground. 
The majority of a Cooper’s Hawk’s diet consists of medium-sized birds. Starlings, doves, pigeons, and robins are common prey, but they can even catch larger birds such as chickens and pheasants. Their method of catching prey is usually in-flight pursuit. However, they will sometimes hunt small mammals like squirrels and chipmunks on the ground. Once they catch something, these hawks will hold the prey away from their body and squeeze it until it is dead. Some will even drown their prey in a shallow pool. Unlike falcons, Cooper’s Hawks wont bite their prey until it stops moving. 
Because of the high-speed lifestyle of the Cooper’s Hawk, many sustain injuries from crashing into tree branches, fences, or even buildings while in pursuit of prey. This could potentially explain the injury to Riley’s wing.

Washington State University