Hell on Wings

Biologists call the agile goshawk "the sports car of the bird world"

04-01-1991 // Jay Heinrichs

Peering from its nest 35 feet up in a yellow birch, the goshawk spotted Idiot. For weeks this foolish human had bumbled up the forest path on daily walks, ignoring repeated warning cries from the bird and its mate. Now the nest held newly laid eggs, and the hawk's compulsion to defend its territory was stronger than ever.

Still, the bird gave fair warning, flying to a tree 20 yards down the trail and calling cak-cak-cak, cak-cak-cak. A creature with any sense would have taken the hint. But Idiot kept on walking, approaching an invisible line across the trail that marked the hawk's territorial boundary. Stop just far enough from the nest, and the bird only calls. Set one foot over the line, and the bird attacks. Idiot crossed the line.

The goshawk plunged out of the tree with outstretched talons, made a tight turn behind the man and swooped just 2 feet above his head. Idiot, looking frightened, began running up the trail toward the nest.

The bird reeled about in a dense stand of birches and made another, closer pass at Idiot; the draft from its wings ruffled the hair on the man's head. A slight flick of the claw, and the bird would be raising scalp. The hawk made a final dive before the man crossed another invisible boundary into neutral territory.

With barely a beat of its wings, the goshawk turned back toward the nest. Idiot leaned against a tree, wondering if he were about to have a heart attack.

This is an embarrassing story, because I am Idiot. The attack (actually more of an avian warning shot across the bow) took place two years ago near my land in New Hampshire. I had watched the pair of goshawks build their nest in early spring and had paid little attention to their frequent calls.

I should have known better. The goshawk has a fierce reputation. Many wildlife biologists consider the bird (found throughout Europe, North America and Asia) to be the world's most aggressive defender of nests. "Many birds of prey will only attack in a do-or-die situation," says Nancy Read, director of the Vermont Raptor Center. "However, the tendency to attack when the intruder is only in the vicinity of a nest seems peculiar to accipiters like the goshawk." Park rangers throughout the northern United States have had to close down trails at times because the hawks buzzed hikers.

But goshawks are not really vicious, claims Read. They don't usually launch major attacks unless you ignore their warnings. Not that these birds are all that predictable, according to Mike Gaylo, who runs a raptor research center in Buskirk, New York. "Some goshawks are secretive; with others you can be a quarter mile away and the sons of guns will attack you."

If the goshawk's defense is impressive, its offensive capabilities come close to astonishing. Its aggressiveness carries over into the pursuit of its prey. The eastern goshawk, the most common of the three subspecies found in North America, hunts birds and mammals throughout its breeding territory in most of Canada and the northern United States. Although about the size of a raven, with a wingspan that rarely exceeds 4 feet, this hawk doesn't shy away from fairly large prey--anything from pheasants to crows and sometimes even small mammals.

The goshawk's strategy can be as notable as its tactics. It shadows deer and other big animals from the sky, waiting for them to flush a pheasant, grouse or other potential prey. When attacking such prey on the ground, the bird sweeps down and deals a crushing blow with its talons.

The most impressive hunting takes place in the air, when the hawk goes after other birds. With its short, rounded wings and a long tail that acts as a rudder, the goshawk pursues the most agile fliers through woods that seem impossible for flight. "It's unbelievable how fast it can maneuver through dense cover and remain completely unscathed," says Mike Gaylo. "The sports car of the bird world," is what Nancy Read dubs it.

If all this seems like macho behavior, think again. It is the mother that defends the nest most fiercely. "The female is more likely to attack and make contact," says Read. "The male is more likely to stand and yell at you."

The female also takes the lead in courtship. In early spring, she chooses a likely nesting area--usually a stand of old trees near some water--and screams to attract a mate. As egg-laying time approaches, the hawks get more and more defensive, driving out anyone who, under the broadest possible definition, might be considered an intruder.

While the female incubates the eggs, the male begins a tireless search for food; each nestling requires more than 14 pounds of food before it begins to fly. When the male returns from the hunt, he sometimes avoids the nest. Instead, he flies just to the edge of the nesting territory, prepares his prey for feeding and makes a sharp clicking sound. The female then darts out from the nest to get the food. Usually she snatches the prey from his beak while he perches, but occasionally the pair will exchange the meal in mid-air: The male flies by and drops the food for the female to catch on the wing. After the delivery, the female dismisses her mate with a shrill cry.

If any food remains after the young have eaten, the mother caches it in the crotch of a tree. Researchers have found that she often does this if the meal is interrupted by an intruder: First the food gets stowed, then the enemy gets dive-bombed. As the young learn to fly, they continue to harass the adults for food, following them around and shrieking.

However, the young often don't make it to that stage. Cold, starvation and predators take their toll on nests. One of the worst enemies is' the raccoon, which climbs tall trees and steals eggs and young even while the mother is on the nest. Raccoons are nocturnal and see well in the dark, but even the most sharp-eyed hawks are night-blind.

Biologists have discovered to their horror that their own research sometimes triggers nest raids. Raccoons have learned to follow the scent of humans as a sign of food, and will find helpless young goshawks at the end of the trail left by tree-climbing scientists. Researchers now spread mothballs at the base of trees or put flashing around the trunk when they begin to study nests.

The relationship between people and goshawks has been complex for centuries. The bird's hunting prowess long made it a favorite of falconers, despite its reputation as one of the most difficult of all birds of prey to train.

The bird's own free-lance hunting gave it its common name: Goshawk derives from the Anglo-Saxon gos for geese and havoc for hawk--hence, a hawk that hunts geese. The goshawk's taste for domestic fowl traditionally made it less than popular with farmers. As recently as the 1940s, the state of Pennsylvania offered a $5 bounty for a goshawk carcass.

Even before bounties were put into effect, the species' numbers seem to have declined in this country, though no one is sure why. We do know that one of the goshawk's favorite food items, the passenger pigeon, had already been hunted to oblivion in the United States by the turn of this century.

The outlook has improved over the past several decades. Forests in the Northeast are getting older, which makes them more livable for goshawks. The U.S. Forest Service declared the bird a sensitive species in the West, which means it is a relatively uncommon animal that depends upon a particular habitat--old trees and small forest clearings. But on a nationwide scale, researchers say that the hawk has recovered some of its former numbers and that the overall population of the species appears to be stable.

Its recovery is impressive when you consider that only a third of goshawks survive their first year. Starvation causes most of the casualties, because prey turns scarce or the birds lack skill in capturing it. "I don't care how good a hunter the bird is as an adult," says Mike Gaylo. "A young bird has an enormous amount of behavior to learn." And one cold week can do in a youngster, fatally weakening it by forcing it to expend precious energy just to keep itself warm.

In search of more abundant food, young goshawks often fly south in the fall, traveling past territories occupied by other birds of prey to sites as distant as the Gulf of Mexico. About once every decade, populations of prey such as snowshoe hares and ruffed grouse crash in the Far North, and older as well as younger goshawks are forced to migrate south. The largest such mass migration on record occurred in 1972, when birdwatchers noted thousands of goshawks in the skies over Pennsylvania, New Jersey and throughout the western Great Lakes region. In just one city--Duluth, Minnesota--observers counted 5,152 of the birds.

Such a gathering is not common. Except when defending a nest, the bird is "fairly reclusive," says Nancy Read. "Most of the ones I've spotted are sneaking off. But when they make a stand, it doesn't pay to stick around."

After the attack two years ago, I made wide circles around nesting goshawks. The guidebooks for northern New England say they begin to nest in late March or early April. So what happened last year when I walked through the woods in mid-March, two weeks before the hawks were supposed to mate? I got attacked again. "They're very, very unpredictable," said Gaylo sympathetically when I told him about the incident.

But if I were Mike Gaylo talking to somebody who had managed to get himself attacked by the same goshawk two years in a row, I know what I'd be thinking. I'd be thinking, What an idiot!

New Hampshire resident Jay Heinrichs is the editor of Dartmouth magazine.

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