Polar bears forced to eat seabird eggs as Arctic hunting ground shrinks

Climate change is forcing polar bears to adapt their diet, as a new study shows they are increasingly foraging for seabird eggs.

Whilst polar bears traditionally eat ringed and bearded seals and even beluga whales, walruses, narwhals, and bowhead whales, rapidly deteriorating sea ice is meaning that they are less able to hunt for their regular sustenance.

As a result, polar bears have started scavenging in areas populated by humans, as well as coming ashore at the same time seabirds are nesting and snacking on their eggs.

A new published in the journal Royal Society Open Science tracked how the bears approached the nesting site over a period of 11 days, as the number of eggs depleted.

To measure the efficiency of these major predators in this new, warmer-age-foraging,  researchers in Canada used drones to monitor them feeding on common eider duck nests on Mitivik Island, in Nunavut.

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"We found that later-arriving bears increasingly visited more empty nests and did not travel in an energy-minimizing way, but became less picky in the clutches they consumed," said lead author Patrick Jagielski, of the Great Lakes Institute for Environmental Research at the University of Windsor.

However, bears did not consistently realise the sudden fleeing of an eider hen meant abandoned eggs were nearby.

"This study demonstrates that, while species are able to incorporate ‘less preferred’ resources into their diet when their primary prey becomes more difficult to obtain, they may not be able to do so efficiently," the authors said.

Whilst experts say that this does not give a generalisable indication as to the new ways that polar bears hunt, it does demonstrate the struggled placed upon animals diets as a result of global warming.

Adding to concern for the longevity of the species, a  study published in Nature Climate Change in July 2020 estimated the species would be starved to extinction by 2100.

Researchers looked both at predictions for climate heating and data on the increasing portion of the year that the bears’ must survive on their fat reserves.

Earlier this month, a paper published in the journal Global Change Biology found that polar bears maintained highly specialized diets of soft blubber and flesh for hundreds of years - even during previous periods of Arctic warming.