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Whoosh! Hungry birds scatter from the feeder; a mourning dove slaps against the picture window, seeking refuge in that “safe” fantasy woodland created by the reflection of trees and bushes in the glass. The cause: the arrival of a Cooper’s hawk.
The hawk picks up the stunned dove. The dove, dead or alive, will be dismembered on the spot or, during breeding season, will be ferried to a “plucking perch” near a nest. The victim becomes a bundle of inert nutrients for adult or for the next generation of hawks. A pile of feathers will remain as a memorial to the dove. If the hawk misses, he or she may set up watch on any nearby perch, even on the feeder itself, intent on succeeding at its next ambush.
This scene, which has become common in residential areas in and around Chicago, would have been a rarity 20 years ago when the Cooper’s Hawk was considered endangered in Illinois. Today, their population has revived. Speculation for their recovery ranges from the outlawing of DDT, which thins egg shells, to the cessation of hunting, to the fact that the birds are opportunistic and have become comfortable in urban and suburban yards, where they can easily catch edge species such as grackles plus songbirds at bird feeders. Doug Stotz of the Field Museum speculates that current abundance is about three times that of the 1960s, judging by Christmas Bird Count data.
Cooper’s Hawks (Accipiter cooperii) are accipiters, a type of hawk with short wings and long rounded tails that help them gracefully maneuver among the trees beneath the canopy of their natural woodland home. Their build allows for sudden bursts of speed as they seize prey with their fierce sharp talons. Prey includes primarily small to medium-sized songbirds such as blue-jays and robins and even quail. They are particularly fond of Mourning Doves and kestrels. They also eat small mammals such as chipmunks, rabbits and squirrels, plus large insects. Accipter comes from the Latin word “to seize.”
Cooper’s Hawks are native to the U.S., breeding throughout this country, southern Canada and northern Mexico. Some migrate short distances. In 1828,
Others called it “chicken hawk.” In 1909, a Mr. Farley is quoted in “Bent’s Life Histories of Familiar American Birds” as saying, “Four times this daring bird (with people standing near) tried to get a chicken out of a hen-yard that adjoined the mixed woods where it had its nest. The people ‘shooed’ the hawk away three times, but at the fourth attempt, despite their cries, it carried off a pullet.” Even humans sometimes came in for attack. “Dr. Fisher (1893) tells of one of these hawks that attacked Dr. C. D. Walcott, while he was collecting fossils, apparently with no provocation; the hawk was repelled but renewed the attack and was killed with a geological hammer.” When possible, hawks were shot.
Male and female Cooper’s Hawks look similar, but the female is much larger than the male. Males have more color. Immatures have brownish backs, yellow eyes and thin dark spotty vertical streaks on a white breast. Adults have dark grey backs, a black crown, orange eyes that deepen to red with age and lateral rust-colored streaks on white breasts. Tails have alternating white and brown bands, tipped in white. Legs are yellow. Sharply hooked beaks mean business when dissecting prey.
In mid to late March or early April, the male begins to defend a small area around a desired nesting spot, often in a location where he has nested before, and waits for a female to drop by. Breeding age is as young as two years. The pair is monogamous during the nesting season. The male selects the nest site, usually a fork in the tree from 20-60 feet above ground near the main trunk of a tree. He builds the platform nest of sticks and twigs within about two weeks, with an occasional contribution from the female. Nests are often lined with bark or green branches
The female lays about four or five pale cobalt eggs, one every other day. While she incubates, the male provides food and will incubate for short intervals if the female is hunting. They may hunt as far as two miles from their nest. Aside from humans, frequent nest predators are great horned owls, raccoons, crows and jays.
Incubation lasts five weeks. Hatchlings resemble little white balls of fluff. This down remains for about two weeks until they molt and begin to feather out. The fledgling period is four to five weeks, with males fledging about four days before females. The young birds stay near the nest, hopping in and out, and they may be fed by their parents for as long as eight weeks.
Although Cooper’s Hawks may repeatedly reuse the same woods, they rarely reuse an old nest. In Perkins Woods, a 7.5 acre Cook County Forest Preserve in northwest Evanston, they have built four or five nests, raised young successfully in one nest (coincidentally when West Nile Virus decreased the number of crows and jays), and have added to that same nest even while working on another nearby. In the last two years, they have nested in single trees in nearby back yards.
Charles Bonaparte, a French naturalist and nephew of Napoleon Bonaparte, was the first person to describe the hawk. William C. Cooper, a New York ornithologist, collected specimens for Mr. Bonaparte. Mr. Bonaparte named the species after Cooper.