Bird of the Week

This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the Cooper’s hawk. Accipiter hawks are not only characterized by their adept ability to hunt prey (largely birds) in the tight constraints of forested ecosystems, but also by their body shape, including relatively short but rounded wings and long tails that improve maneuverability in the woodlands. Species of these “sparrowhawks” found locally include northern goshawks, sharp-shinned hawks and Cooper’s hawks. Their relatively long legs and talons allow for quick, stalk-and-capture hunting methods. Choice prey in this region include medium-sized species of birds (dove, robins, jays, grouse, etc.), as well as rodents, hares and bats. When not pursuing prey, flight is characterized by a graceful flap-flap-glide. Cooper’s hawks share common field marks with their smaller cousin, the “sharpies,” making identification sometimes challenging. But there are a few key distinctions that can help with parsing them out. First off, one of our chapter members once offered that Cooper’s hawk’s heads, while perched, appear much stockier and squared off like that of a linebacker (think less-distinctive neck). Their capped dark head does, however, have more of a distinct color separation from the slate gray on their back and wings. They have rusty-red barring across an otherwise pale breast and belly, with feathering carrying further down than sharpies to obscure their legs. When in flight, the Cooper’s head sticks out more prominently from the leading edge of the wing creating more of a “t-shaped” profile. A long tail has alternating bands of black and gray with a more curved tail profile and white terminal band. Juvenile birds are brown-backed with clear streaking on the breast and lack the red eyes of maturity. These hawks are no strangers to wooded residential neighborhoods, as they routinely catch prey birds off-guard at feeders. In fact, after this species rebounded from the banning of DDT pesticides, it has shown steady increases in population trends, likely due to supplemental food sources congregated in folks’ backyards. Currently, the biggest concern with human-afflicted fatalities is collisions with windows, whether residential or automobile. Interestingly, according to some research, these birds survive lots of broken bones in their harrowing chases through the trees to seek prey. These birds can live for more than 20 years. Females are larger than males and, thus, males often are careful to approach and court prospect mates, often bowing and offering flight displays to woo. Once pairs are formed, they tend to be long-term. Males largely build the nests in March, while females provide the majority of egg incubation, typically leading to approximately two to four surviving fledglings. For information on events, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.