Nature Notes: Cooper’s Hawk
Sitting around the dinner table with friends a few months ago, conversation turned to the large bird feeder visible through picture windows. Our host clearly enjoyed watching his many visitors, but complained about losing song birds to a fast flying raptor. He told of seeing one sparrow being swept away in a burst of feathers. Upon careful questioning by a keen birder at the dinner table, the conclusion was that the interloper was probably a Cooper’s hawk.
The Cooper’s hawk is a member of the accipiter family, which includes the smaller sharp-shinned hawk and the larger Northern goshawk, all of them found in Maine. Accipiters are characterized by short, rounded wings and long tails that allow them to maneuver at surprising speeds in the deeper woods that are their preferred haunts. Like other raptors, these highly effective hunters have keen vision, sharp talons and beaks for clutching and eating prey, and they are capable of taking birds in flight at high speeds. Because of its willingness to take poultry on the ground, the Cooper’s in the past was sometimes cursed at using the derogatory name “chicken hawk.”
A mature Cooper’s hawk is approximately 17” long with a wing span of 33”. Weight is 1 – 1.5 pounds, with the female considerably larger than the male. Depending upon the age of the bird, coloring ranges from browns and whites, to softer red, white, gray, black and steel blue, resulting in a striking pattern that serves as good camouflage in cover. The head is a bit oversized compared to other birds, with a short, hooked bill, red eyes and black hackles that may be raised – this bird has the brooding glare of any serious predator.
The Cooper’s primary range goes from southern Canada to northern Mexico, and from coast to coast. They prefer sizable tracts of woodland but will take advantage of more open terrain and scattered woodlots to find food. The bird is most often visible in numbers during annual migrations north or south, although some have been observed in urban areas where they take advantage of large flocks of rock pigeons and mourning doves.
Speed and stealth are the primary advantages used by the Cooper’s hawk in hunting prey. Springing from cover, or swooping in from above to nab unsuspecting prey, these birds would make an F18 pilot proud. While they favor small to mid-sized birds of all kinds, rabbits, squirrels, mice, bats, snakes and frogs are also fair game. As noted in the opening paragraph, an active bird feeder makes a good hunting ground for this opportunistic killer. Your backyard may also be safer than hunting in the deep woods – a study of over 300 Cooper’s skeletons found in the forest revealed 23% had fractures of the chest resulting from high speed collisions with trees and branches.
Breeding takes place once a year in the spring, and the birds are monogamous during one season. Favoring good weather days, the male will make slow dives and arcs around the female showing off his plumage until she gives in to his flirtatious maneuvers. After mating has occurred, the male has been observed bowing to his new mate. The birds cooperate in building a large nest of sticks, high up in a tree with good visibility and access. 3 – 5 cobalt blue eggs are incubated by the female for about one month until the downy white chicks are born. The male helps secure food until the chicks are ready for flight, about one month after birth, and at 2 months of age the young are on their own.
The Cooper’s hawk can live a fairly long life, up to 12 years in the wild although one bird was documented at 20 years. They are sometimes captured by larger birds of prey, but the birds are now protected from shooting along with other raptors. Now that DDT and other pesticides are more closely regulated, the biggest threat to Cooper’s hawks is loss of habitat.
A few years ago I was in the forest one quiet November afternoon, watching a deer trail from a ladder stand about 18 feet off the ground. In response to a sudden flutter of wings, I turned my head to find a Cooper’s hawk sitting on a limb about 5 feet away from my face. The hawk fired a look at me that made it clear I had no business interrupting her hunting routine, and then she flew off to find more private hunting ground. I hope the hawk had more luck that morning than I did!