Vanishing Arctic gulls puzzle biologists

Biologists say they don't know what's happened to the population of ivory gulls in the eastern Arctic.

The all-white gulls migrate north in the summer, nesting on islands like Ellesmere and Devon.

But Inuit in High Arctic communities say they're seeing fewer of the birds, and surveys by the Canadian Wildlife Service show the birds' population has dropped.

Karel Allard, a Ph.D. student at the University of New Brunswick, has been working with the Canadian Wildlife Service on Devon Island this summer.

He says this year and last, biologists conducted surveys of known ivory gull colonies.

"They visited many places where there had been hundreds of breeding birds," he says. "In many cases these sites no longer had any birds at all."

Researchers say they don't know why the birds have disappeared.

Mark Mallory, a seabird biologist with the Canadian Wildlife Service in Nunavut, says Inuit don't hunt the gulls.

Mallory says the decrease could be due to contaminants, climate change or overhunting on their wintering grounds down south and in Greenland.

"We're pretty confident that it's not something to do with the breeding grounds, because they're doesn't seem to be any obvious signs of change at the colonies up here," he says.

"Even though the ice is changing in the Arctic, there's still lots of ice around the communities where they've been seen for years and years, and they're just not being seen anymore."

Mallory does say the crash in the birds' population is significant. He says ivory gulls could end up on the list of species at risk in Canada.