Each spring and summer, Old Crow Flats is host to half a million waterbirds. They gather on the shallow lakes and marshes to nest, raise their young, moult, and prepare for the flight back to their wintering grounds.

Debbie van de Wetering, a wildlife research technician with the Canadian Wildlife Service, has studied ducks on Old Crow Flats for the past couple of summers. She's constantly astonished by the teeming life of the Flats.

"I took some photographs just above the water, looking down, and it's like a miniature jungle down there. It's incredible."

Van de Wetering's particular interest is the Barrow's Goldeneye, a diving duck that visits Old Crow Flats during its annual moult. The ducks spend three to four flightless weeks on the Flats while their old flight feathers drop out and the new flight feathers grow in.

"There are thousands of males and a few non-breeding females that fly there just to moult," says van de Wetering. The females with ducklings probably moult nearer their nesting sites, she says.

During the moult, ducks rely on swimming and diving to escape predators and find food. Many go to specific moulting sites, which tend to be large, shallow lakes, free of disturbance, van de Wetering says. Old Crow Flats, with more than 2000 lakes spread across 600,000 remote hectares, is ideal.

The Flats are particularly important to Barrow's Goldeneye because of the ducks' limited distribution. About 80 percent of the world's population lives in British Columbia, Alaska and the Yukon. Small populations also live in eastern North America and Iceland.

British Columbia has the largest population of Barrow's Goldeneye, but scientists still don't know where the males of that group moult.

"They tend to moult in very secluded areas, but it's surprising to me that we don't know where the males moult in B.C.," says van de Wetering. Old Crow Flats is the only known moult site in western Canada, but there must be others, she says.

The population that moults on Old Crow Flats appears to winter off the coast of Alaska, she says. Birds were banded in the 1970s and 1990s, and so far all returned bands have come from Alaska.

In the spring, Barrow's Goldeneye are found through much of the Yukon, breeding in forested areas near water.

"They're very territorial," van de Wetering says. "On small ponds, when they're nesting, there will be only one pair per pond, and the Barrow's Goldeneye male will fight and drive other males away."

They nest in tree cavities, often quite far from the lake or pond. When the ducklings are ready to leave the nest, they fall out of their tree and walk to the water.

By then, the male ducks have already left the breeding areas. Once the female is incubating eggs, the male joins a flock of other males and flies to Old Crow Flats for the moult. They arrive in the thousands. In a survey of just 30 lakes this summer, van de Wetering counted 8000 Barrow's Goldeneye.

She traps and bands the birds, and measures the rate of feather growth. Her goal is to determine the factors that make a habitat suitable for the moult.

"On the management side, that will tell us what it is about the Old Crow Flats that's so important as a moulting site, not just for Barrow's Goldeneye but for the other ducks that go there as well."

There is still a lot to learn about Barrow's Goldeneye, says van de Wetering.

"It's important when you think that we're basically the stewards of the species, because it doesn't exist in large numbers anywhere else," she says.

The Barrow's Goldeneye study is part of a larger three-year program of co-operative waterfowl and habitat studies begun in 1994 by the Canadian Wildlife Service and the Vuntut Gwitchin Tribal Council. It will help form the foundation of a management plan for the Old Crow Flats Special Management Area, created under the Vuntut Gwitchin land claim settlement.

For more information about Barrow's Goldeneye and Old Crow Flats, contact the Canadian Wildlife Service in Whitehorse, 393-6700, or see the Yukon State of the Environment Report 1995, available from Environment Canada in Whitehorse.