WHITE BEARS, BLACK OIL.

In the fight to stop the Bush Administration plan to drill for oil in the Arctic National Wildlife Refuge (ANWR), there's been little attention paid to polar bears. But ANWR is one of only two principal polar bear denning areas in North America, and activists say the shrinking status of the continent's other major population of white bears--on western Hudson Bay, near Churchill, Manitoba--is a compelling reason to keep hands off Alaska.

To find out how the Hudson Bay bears are doing, three Canadian Wildlife Service scientists, Ian Stirling, Nicholas J. Lunn and John Iacozza, monitored the condition of adult animals and conducted a census of new and yearling cubs between 1981 and 1998. They found that adult bears weigh less now than they used to, an indicator of declining physical condition. The females are having fewer cubs, and a smaller number of those cubs are surviving. The reason, the scientists suggest, is earlier break-up of winter ice, which leaves the bears less time to hunt and fatten up. The effects are most pronounced on pregnant females, who need fat reserves to support themselves while they den, give birth and lactate, all while fasting for months

The Churchill polar bear population has not declined--yet. Still, the scientists' report concludes, "If the trends continue in the same direction, they will eventually have a detrimental effect on the ability of the population to sustain itself." With overwhelming evidence that global warming has already begun, those trends are certain to threaten the Hudson Bay bears.

Their counterparts in ANWR are also at risk. The Refuge's 1002 Area, which would be the site of oil exploitation, supports the highest density of denning female polar bears of any area along the Beaufort Sea, according to a study reported by the U.S. Fish and Wildlife Service. "The coastal plain is the most significant on-land polar bear denning habitat in the U.S.," says the Wilderness Society.

Even the Department of the Interior's official website sees a conflict: "Because the highest densities of maternal land denning overlap with potential oil and gas development, ... disturbance from exploration and development activities could cause den abandonment by pregnant females or females with newborn cubs."

The oil industry's plans to drill in ANWR could threaten the refuge's hardy ursine survivors and push the Hudson Bay's polar bears to the edge. CONTACT: Arctic National Wildlife Refuge, [e-mail], www. fws.gov.