For the first time since the 1980s, wildlife managers in the Yukon-Delta National Wildlife Refuge are killing arctic foxes that steal thousands of waterfowl eggs and cache them under the tundra for leaner times.
The scavengers are among the culprits in an old, international mystery: Why are Pacific black brant -- a small goose that travels between Mexico and Alaska -- steadily declining?
Partly to blame are ATVs that disturb coastal nests, increasing fall floods and hunters who take several thousand brant every year, managers say. Efforts are under way to control some of those factors, including hunting reductions across the Western U.S.
But foxes in the Western Alaska refuge, about 400 air miles west of Anchorage, may be the biggest reason black brant numbers are only about two-thirds what they were in 1960, managers say. It's on that marshy plain that most of the world's 115,000 black brant gather each summer in several nesting colonies.
Hunters in Canada, Mexico and the U.S. take about 14,000 black brant a year, said Tom Rothe, waterfowl coordinator for the state Department of Fish and Game. Native subsistence hunters on the delta take about 4,000 of those.
"We make soup out of it," said Anthony Boyscout of Chevak, a village in the 19 million-acre refuge.
But a single fox will swipe several hundred eggs in a matter of weeks if it can't find tundra mammals to eat. The foxes frighten away weak birds on the edges of colonies, gripping the large eggs in their mouths and ferrying them to nearby burrows.
"They'll just keep coming and coming," Rothe said.
State and federal wildlife managers are reducing the number of foxes as part of a $100,000, five-year study initiated this year by the U.S. Geological Survey, said research associate and wildlife biologist Michael Anthony.
In March, biologists trekking across the snow-covered refuge killed about 20 foxes using spring-loaded Conibear traps that snap shut around necks, Anthony said. Biologists hope the fox killings will protect a sample colony of about 4,000 brant that nest at the mouth of the Tutakoke River, he said.
About 50 foxes were removed from the refuge during a four-year period in the mid-1980s, he said. Brant reproduction rates recovered quickly, jumping from less than 10 percent to more than 80 percent, he said.
The program wasn't continued, and the numbers began falling again in the 1990s, he said.
The research will help create a model that predicts when foxes are likely to raid nests and, therefore, when they should be eradicated, he said. The study will also gather information to help scientists estimate vole numbers, which guide the number of foxes, he said.
One big question is whether increasing fall floods are killing foxes and voles, he said.
Bethel-based refuge manager Mike Rearden said a fall storm last year, the biggest in memory, sent saltwater at least 10 miles inland. The storm, fueled by rising global temperatures, may have killed thousands of voles and some foxes, he said. The full extent of the damage may never be known, but Rearden will have a better idea once the snow melts.
State and federal managers from California to Alaska have been trying to protect brant for years, Rothe said. They hope to bring their numbers to 1960 levels of about 150,000, he said.
Already-tight recreational hunting seasons were halved last year in four West Coast states, including Alaska, to further protect the bird. The fall season on the Alaska Peninsula, which begins Sept. 1, now lasts just a month, he said.
Federal regulations will also reduce subsistence hunting on the delta beginning this year, he said. Hunting around brant colonies isn't allowed at all. Elsewhere on the delta, brant hunting won't occur until newborn birds fly, usually around early August, he said.
The Native village corporation in Hooper Bay, north of the Tutakoke River, restricted ATV vehicles from traveling on corporation land near a large colony last year, said Myron Naneng, a member of the Alaska Migratory Bird Co-Management Council, which recommends subsistence harvests in Alaska.
In part because of those efforts, the number of nesting pairs jumped from 1,000 in 2004 to 4,000 last year, Naneng said.
The limitations are important, said Richard Tuluk, tribal administrator in Chevak.
"We need to use these resources for our dinner tables and to provide nutrition for the young ones," he said.
Daily News reporter Alex deMarban can be reached at email@example.com or 257-4310.