September 10, 2009

Arctic-nesting geese opt out of migration

The U.S. Geological Survey says global warming has resulted in some arctic-nesting geese electing to spend the winter in Alaska instead of Mexico.

USGS scientists said they've discovered the winter distribution of Pacific brant -- a small, dark sea goose -- shifted northward from Mexico to sub-Arctic areas as Alaska's climate warmed in the last four decades.

The USGS-led survey found until recently, about 90 percent of Pacific brant wintered in Mexico. Now as many as 30 percent are opting to spend their winters in Alaska. The researchers said fewer than 3,000 brant were detected wintering in Alaska before 1977, a number that has jumped to as many as 40,000 birds now.

This increase in wintering numbers of brant in Alaska coincides with a general warming of temperatures in the North Pacific and Bering Sea, said David Ward, the study's lead author and a USGS researcher at the Alaska Science Center. This suggests that environmental conditions have changed for one of the northernmost-wintering populations of geese.

The research that included Christian Dau, Lee Tibbitts, James Sedinger, Betty Anderson and James Hines is detailed in the journal Arctic.