October 31st, 2012
We were thrilled to receive a new set of images from photographer Doug Brown this past weekend. He had been photographing migrating raptors along the Texas Gulf coast and snagged some great shots. The hawk in the image above is a second year bird. While the hawk has mostly the gray feathers of the adult, as well as the rufous color on the breast, some brown feather remain on the back. Juvenile Cooper’s Hawk have brown backs with some white spots on the upper back. They molt into the adult plumage with a solid gray back during their second summer. This bird also shows a yellow-orange eye color which is indicative of age in all accipiters. However, the rate of change in eye color is variable and cannot be used to definitively age an accipiter.
Cooper’s Hawks belong to the accipiter family, also known as ‘forest’ hawks. All three North American species, the Sharp-shinned Hawk, the Northern Goshawk, and the Cooper’s Hawk, have similar body shapes and are adept at pursuing prey through dense vegetation. Cooper’s Hawks are primarily bird-eaters, although they also take small mammals and insects.
In the above image, a few brown juvenile feathers remain on the bird’s back. Additionally, the gray ‘cap’ that is characteristic of the adult Cooper’s Hawk is not yet complete, also identifying this bird as being in its second summer. Note the eye color on this hawk is still yellow. Cooper’s Hawks have a prominent supercilliary bony ridge above their eyes as do Northern Goshawks. The Sharp-shinned Hawk lacks the bony protrusion, giving it a bug-eyed appearance.
The above image shows an adult Cooper’s Hawk with a solid gray back and a pronounced gray cap on its head.
Finally, here is a juvenile Cooper’s Hawk with the typical brown back with white spots, the light-colored head, and the very pale eye color. It is important to remember that eye color alone cannot be used to accurately age any accipiter.