Shrinkage of Arctic sea ice is now pushing polar bears in Canada's Hudson Bay region to search for new food in bird nests.
This is what has been discovered by researchers from Carleton University in Ontario, supported by the Canadian Department of the Environment.
A polar bear in northern Hudson Bay can eat hundreds of seabird eggs in a day, according to a study published this week in the scientific journal Proceedings of the Royal Society B.
Scientist Samuel Iverson, the report's lead author, says he has seen a rampage in which a polar bear ate his way through 300 common eider nests, each containing four to five eggs, over a 48-hour period.
Along with nesting birds on the ice, those so on the sides of cliffs, such as thick-billed murres, are also victim of polar-bear raid. "They're right at the foot of cliffs and make their way along the edges of an egg and go to another," says Iverson.
Iverson believes that the Arctic warming has reduced sea ice season 60 days in northern Hudson Bay – with the thaw coming 30 days earlier in the spring and frost is delayed 30 days in autumn – and is forcing the bears to seek other sources of food.
Although these bears have perhaps occasionally eaten bird eggs in the past, researchers believe they now target the nesting colonies. Their data show that even the incursions of polar bears in nesting colonies of seabirds have increased more than sevenfold since the 1980s.
This story is posted on Alaska Dispatch as part of Eye on the Arctic, a collaborative partnership between public and private circumpolar media organizations.