Air to Bear : Biologist Tracks Elusive Polar Bears From Copter for Census

A gun at his feet and a visor shading his eyes, Steve Amstrup scans the frozen Beaufort Sea from a helicopter.

He is 70 miles off the north coast of Alaska, and the world below looks like a cracked eggshell: dazzlingly white, veined with black water and ridges of churned-up ice.

Prime polar bear country--and Amstrup’s laboratory.

There’s no land, no landmarks--just a floating desert constantly being remade by wind and currents. But as usual, the 42-year-old federal wildlife biologist finds what he is looking for.

“Bear tracks at three o’clock,” he says suddenly, and the pilot circles down to pick up the chase, following a trail of foot-long tracks that leads across snowy ice floes and outcroppings of glacier-blue ice.

In a minute, the bear comes into view--a shade blonder than the ice and fleeing across it, glancing back at her pursuers. Behind her run two tiny cubs, struggling to keep up and looking from the air like dust bunnies swept along in the helicopter rotor wash.

“Back off so she doesn’t lose the cubs,” Amstrup says.

He measures and loads a tranquilizer dart into his rifle, then harnesses himself to the back seat of the helicopter and steps out on a skid. The helicopter comes to within 6 feet of the running bear, and Amstrup fires.

“Got her--upper left shoulder,” he shouts, stepping back into the aircraft. Then, making sure to steer the bear away from any open water or rough boulder patches, the helicopter waits for her to go down.

Over the next hour and a half, the three bears were tranquilized, poked for blood samples, measured and weighed. The cubs were ear-tagged and tattooed, as their mother was years ago.

With colleagues in other Arctic nations, Amstrup is gradually building the first comprehensive population data on the elusive animals, the largest non-aquatic predators in the world.

Amstrup and other researchers say polar bear numbers in Alaska are stable and healthy at about 3,000 to 5,000. The worldwide population is estimated at between 25,000 and 40,000--most of them off the coasts of Canada and Russia.

They hope to gather enough baseline information to gauge how well polar bears handle potential threats: the increasing number of people and human activities in the Arctic, proposals for more Arctic oil development, possible global environmental changes.

“This is literally ends-of-the-Earth fieldwork, and there’s very little support system out there,” said Bruce Batten, a spokesman for the U.S. Fish and Wildlife Service, which employs Amstrup.

The difficulty and danger for humans of getting around in polar bear country has helped protect the bears. But the bears’ inaccessibility also has taken a toll on his research in time, money--even human life.

In 1990, two of the program’s researchers and a pilot died when their plane disappeared over the icecap while scouting for bears.

That disaster, along with spiraling costs and budget declines--a day on the ice costs about $3,500--have led Amstrup to cut back on fieldwork, from two visits to the ice to just one, in the spring.

“There are relatively few animals that are as logistically difficult and expensive to study as polar bears, and that’s one of the reasons why we know so little about them,” Amstrup said.

“Just getting basic population data isn’t easy if you’re working in the Arctic and you’re paying 25 cents a whop for a helicopter and you’re covering an animal where each one has a range the size of Montana.”

Amstrup’s base camp is BP Exploration’s Endicott facility, a drilling operation a few miles offshore east of Prudhoe Bay. The oil company provides logistic help--room and board, office space, ground transportation. Amoco and Arco provide money for radio collars and other program needs.

High winds or temperatures lower than 30 below zero kept Amstrup off the ice for two of the four weeks he spent on the North Slope this spring.

Pilot Paul Walters of Trans-Alaska Helicopters in Anchorage calls his Bell 206 aircraft the “Hotel Bell,” and adds it’s none too comfortable on an Arctic night. Still, he has returned to help Amstrup since 1989.

“I’ve done work with grizzlies, wolves, moose. But this is the most exciting,” said Walters, who also helps weigh the bears.

“It doesn’t get old looking at them.”

Amstrup, tall and blond like the bears, has captured more than 1,000 in the 11 years he has gone out on the ice. They range from 11-pound cubs to 1,400-pound males; by now, there is a growing number of animals he has been monitoring for years--the ones he calls “old friends.”

The cubs’ mother is one.

“It’s really neat to see them again and say, ‘By God, she’s 23 and she’s got another litter,’ ” Amstrup said.

He lifts the sow’s heavy head gently to move her chin off a piece of jutting ice.

“How you doing?” he asks as she blinks and sighs at him, licking canine teeth as long as his thumbs. “That’s a healthy bear.”

Then he begins spreading green tattoo ink on the inner lip of one trembling, snoring cub.

“I hate this part,” he says.

But Amstrup insists the that ordeal is like a doctor’s checkup: temporarily stressful and uncomfortable but without permanent damage.

Amstrup collects body measurements and data on fat content and reproductive history. He takes a shaving of claw, which can be tested to see where the bears have been, and often takes a tooth for aging.

The mother bear wears a radio collar, which helped Amstrup find her. He was among the first to rely on radio and satellite signals to track polar bears.

Male bears’ habits and wanderings remain more mysterious than females’ since scientists cannot collar them. Their necks--up to 4 feet around--are bigger than their heads.

Male bears provide some of the tensest moments Amstrup has had on the ice. If he darts a female who is part of a breeding pair, the curious male may come around to see what’s happening.

Amstrup carries a pistol for such instances, but he has never had to shoot a bear. Starting the helicopter is usually enough to scare them away.

One day this spring, a female with a yearling changed the rules. As the helicopter came low and he aimed to dart her, the mother suddenly turned and leaped 4 feet into the air, trying to bat down the helicopter.

She came within a foot of it.

“I don’t even like to think how close we came to disaster,” Amstrup said. “It was incredible--I’ve never seen a bear do that.”

Polar bears show little fear of humans, who are often the same size as the bears’ staple food: seals. But bears have more to fear from humans than vice versa, Amstrup said.

He worries more about the animals’ increased contacts with humans in general than he does about oil development specifically. He thinks the oil industry could be regulated and educated to coexist with polar bears.

That view wasn’t shared by everybody during the debate over whether to open the Arctic National Wildlife Refuge to oil drilling.

Drilling opponents cited Amstrup’s studies on polar bear maternity denning, which show a concentration of dens on the refuge’s disputed coastal plain. The refuge, which makes up about 13% of the Beaufort Sea coastline, was home to 43% of coastal dens.

Both houses of Congress have passed energy bills, and neither agreed to allow drilling in the refuge. Lawmakers certainly took the fate of the bears into account. “The polar bear is probably the premier symbol of the Arctic,” said Batten, the Fish and Wildlife spokesman.

To Amstrup, there are few animals as spectacular.

“Polar bears have clearly captured people’s imagination,” he said. “They’re an incredibly familiar yet mysterious creature.”