"Life in the Bering Sea" by: Nancy Marie Brown (Research/Penn State, Vol. 15, no. 2 (June, 1994))

The scattering of islands in the Bering Sea, step-stones between Russian Chukotka and Alaska, are a-flurry with birds. Nesting on the green margins of the islands' tops, on each lip and crevice of the low sea-cliffs, scurrying harum-scarum along the nest ledges, flocking out to sea in search of food, they would seem the perfect monitors of the sea's food web: Catch them, weigh them, and calculate the health of the deep. Correct?

Maybe not. A study by Chris Haney, assistant professor of wildlife technology at Penn State Dubois, and his Russian counterpart, Alexander Golovkin, found that the weight of some seabirds fluctuates widely.

The Least Auklet, for instance, a big-billed, bluebird-sized diver, can lose up to 21 percent of its body mass in one day of egg-sitting.

The nesting Parakeet Auklet (three times bigger, with a round, red bill) can lose up to 16 percent of its mass.

Said Haney, "We're beginning to modify our views of how sensitive the birds are to environmental disturbance or damage that would disrupt their food supplies." No coal-mine canaries, arctic seabirds may not, as scientists had hoped, sound an immediate alarm when the fishing pressure from the many multi-national fleets in the area begins to overtax the environment.

"This ability to fast, although the birds can't fast for very long, tends to make seabirds a little less sensitive as indicators of environmental trouble," said Haney. "Until fasting adaptations are better understood, the reliability of seabird body conditions used to monitor marine conditions will remain uncertain."

Earlier studies had calculated the cost of hatching chicks at 3 to 6 percent of the parents' weight, a loss one theory saw as a gain: As a "pre-programmed anorexia," or an "adaptive weight regulation," Haney explained, it made foraging easier, since a lighter bird could wing further over the sea to find food.

"We found there's so much variation in body mass daily," said Haney, who caught the birds off their cliff-edge nests with J-shaped metal hooks or jumbo butterfly nets, "we're unsure how a 3- to 6-percent weight loss could be detected against this backdrop."

His and Golovkin's results, he added, "suggest the earlier findings on weight loss have more to do with normal shifts in activities or feeding schedules than with any evolutionary adaptation in the birds."

J. Christopher Haney, Ph.D., is assistant professor of wildlife technology at Penn State Dubois, College Place, DuBois, PA 15801; 814-375-4769. Alexander Golovkin, Ph.D., is laboratory chief for rare and endangered species at the Institute for Nature Protection and Reserves, Moscow. Their research is funded by the U.S. Department of State and the city of St. Paul in the Pribilof Islands; they presented it at the January 1994 meeting of the Pacific Seabird Group in Sacramento, CA. Reported by Scott Turner.