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Death From Above

Small birds and rodents are learning the hard way that the Cooper's hawk is back in town.



On a cold morning a few weeks ago I looked out the window of my Humboldt Park apartment and saw the aftermath of a violent attack. The perpetrator was still tearing apart the victim right out in the open. I went outside, stealthily made my way to a nearby porch, and trained my binoculars on a branch above me, where a young Cooper's hawk was eviscerating a bird that was too far gone to identify, its down and feathers sinking on a light breeze to the snow below.

I called the Democratic precinct captain, who told me he'd seen a hawk harassing cardinals in the branches of a tall shrub on Francisco Street. I went over to take a look, and a woman from that network of snoops and gossips who pose as dog walkers pointed to a building with a crowd of sparrows at the side window.

Soon I was talking to Dick Bates, a retired banker and confessed "bird feeder"--he hangs out one of those canisters of seed that keep chickadees, finches, and even cardinals in a state of dependence. "I never saw that hawk catch a bird," he told me. "My feeder is tubular. It's encaged, so the pigeons and the big birds can't get at the food. The first time I saw the hawk he was perched in the courtyard. It was quiet. All the little birds had scattered. It was during that hard cold spell, below zero. The sparrows, they go through 40 pounds of seed a week. That hawk was very patient, very still. I went out, and when I came back an hour later he had something. I couldn't tell what, and at first I thought it was a mouse or a rat. I think they like squirrels better anyway. But then I saw the feathers."

Cooper's hawks are crow size and cat eyed, by turns calm and reserved or curious and playful. Like most aerial predators, they're dark above and light below, camouflaged from either vantage. They have slate gray wings, brown or ruddy shoulders, and cream breasts with rufous brown streaks that are vertical in young birds, horizontal in adults.

Like their cousins the sharp-shinned hawks, Cooper's hawks feed primarily on other birds. They're forest hunters given to high-speed pursuits and tight, sinuous turns. In city parks I've more than once heard an insistent wing beat from a flock of pigeons taking off and turned to see them separating, some swirling right, others left, while in the center a single bird veers and strains, a hawk a few feet behind.

Three decades ago Cooper's hawks were on the verge of disappearing--victims of DDT, which was widely used after World War II. Sparrows and pigeons ingested small amounts of the pesticide, and their predators ingested more. High concentrations of DDT in the female hawks produced weak egg-shells that broke in the nest. Populations of Cooper's hawks--along with those of bald eagles, peregrine falcons, and most other native raptors--went into a steep decline and only began to recover after the federal government banned DDT in 1973.

"I was amazed to find Cooper's hawks along the Des Plaines River for the breeding-bird survey in the mid-80s," says Alan Anderson, a board member for the Chicago Audubon Society. "They were very uncommon, and now they're everywhere."

Audubon and thousands of volunteer birders do a national census every Christmas, and the Chicago count has surveyed much of the city and a few western suburbs for almost 40 years. From 1967 to '85 the birders listed just five Cooper's hawk sightings in the area. At Christmas 2002 there were five, and in the 2003 count, 14.

It's people like Dick Bates that are turning the Cooper's hawk into a common city bird. The hawk that visited his feeder stayed for at least three days and struck more than once. A Cooper's hawk sees a backyard feeder the way a lion sees a watering hole on the African savannah--as a magnet for the unsuspecting.

The agility that allows these hawks to chase their prey through tangled forests serves them well in the cluttered urban landscape around feeders, but they're also capable of stealth and intimidation. The hawk at Bates's feeder simply sat very still, camouflaged in the crook of a tree, patiently waiting for the sparrows it had scattered to come back to the feeder. Other local birders tell of Cooper's hawks flying at bushes to scare birds into the open or simply landing on the ground and pushing under the foliage.

Karen Mansfield, who monitors Clark Park on the north branch of the Chicago River for the Bird Conservation Network, watched a pair of young Cooper's hawks try to corner a squirrel last September in a lot near the park. One hawk stalked the squirrel through the low, brushy grass, hopping and sometimes fluttering forward. It grabbed the squirrel in its talons, only to have it struggle free. The squirrel ran toward a tree, but the second bird swooped down, sending it scurrying back into the brush.

Mansfield watched the confrontation for a quarter of an hour. At one point the first hawk faced off with the squirrel, just a foot separating them. The squirrel made tentative moves toward the tree, but the first hawk blocked its escape. The hawk seized the squirrel several more times, but each time it wriggled away. Finally it found some denser brush, and the hawks gave up the hunt, apparently too inexperienced at finishing off quarry.

Just as many European settlers found it easier to claim land after disease had ravaged the native population, Cooper's hawks may be taking advantage of the damage done to local crow and blue jay populations by the West Nile virus. Crows and blue jays died off in large numbers during the epidemic. For reasons that aren't entirely clear, other birds, both common and uncommon, were less affected. Carol Nelson, a Bird Conservation Network monitor for Rosehill Cemetery, says that crows and jays serve as sentinels, shrieking out a warning when they see a raptor and alerting every bird around. "Once at Montrose I saw a kestrel hunting," she says. "The crows were sounding the alarm, and the jays were making a racket. Most of the sparrows scattered, but a couple of them just didn't get it. One hung around too long, and he got eaten."

Crows will also "mob" hawks to drive them away. Joe Lill, another Audubon Society board member, keeps an eye on a mating pair of Cooper's hawks in a small woods in Evanston (whose location he prefers to keep secret). They've nested, but no hatchlings have been seen. Lill speculates that crows may drive the pair from the nest too often, allowing the eggs to get cold.

Wherever they're hatching, Cooper's hawks seem to have found their urban niche. A recent AP report describes one that took up residence inside a Home Depot in Ohio. The store managers said they planned to leave the bird alone until it cleared out all the pigeons and sparrows living in the store. But the most dependable food supply may be the backyard feeder. Cornell University does a national survey of birds spotted at feeders, mostly in urban and suburban backyards, and publishes an annual top-25 list by state. Cooper's hawks entered the Illinois chart three years ago in 25th place. Last winter they were in 23rd. We're likely to see more of these beautiful raptors veering around three-flats and scattering birds outside the window.

Art accompanying story in printed newspaper (not available in this archive): photo/Jerry Kummery.

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