Polar bears are increasingly hungry and are struggling to hunt for seabird eggs

Due to global warming, polar bears have less and less food available. Thus, they feed on seabird eggs and rummage through the litter.

Global warming is putting polar bears to the test now more and more hungry. If until some time ago they still managed to hunt seals, their favorite prey, today they feed more and more often on bird eggs and go to areas populated by humans in search of food, for example in landfills. A disturbing scenario emerges from a recent study conducted in the Arctic and published in the scientific journal Royal Society Open Science.

Polar bears hunting for seabird eggs

To monitor the behavior of polar bears, a team of Canadian scientists from the University of Windsor spent about 10 days on theMitivok Island, in Hudosn Bay (the vast inlet of the Arctic Ocean). This area is home to thousands of seabirds, including eiders, sea ducks that nest in the Arctic region.

Using drones, the experts observed the bears approaching nesting sites over a period of 11 days, as available eggs ran out quickly.

“We found that the bears that arrived later visited more and more empty nests and did not travel in a way that minimized energy, but became less picky,” explains Patrick Jagielski, lead author of the research.

Mitivok Island has become a favorite of polar bears in recent years, as the glaciers have become increasingly difficult to hunt for seals and other species they love. Thus, polar bears come to that area especially in spring and early summer, when seabirds nest. “Some stop on the island to snack on eggs,” says Jagielski.

“Polar bears are like teenagers. They are always hungry. " explains Robert Rockwell, an ecologist at the American Museum of Natural History who has been studying this species for 50 years.

For this species, which has always been used to feeding mainly on seals, changing eating habits is not at all easy.

"Polar bears are so specialized in hunting seals that they may have a harder time adapting to Arctic warming," points out paleontologist Larisa DeSantis of Vanderbilt University who has delved into the evolution of bears' diets over the centuries by examining their skulls kept in several museums. “The shift to hard food consumption in the 21st century is also worrying. Polar bears could reach a tipping point and be forced to consume less preferred foods (despite having skulls and metabolisms unsuitable for such a diet). Among these, in fact, the carcasses and garbage, in addition to the bird eggs we talked about earlier.

Although bears have not yet become proficient egg hunters, the impact on seabirds such as eiders could be very severe, considering that already 30% of the colonies of these species have been attacked by bears. It is not excluded, therefore, that the seabirds of the area will be forced to nest elsewhere to escape the hungry bears.

Polar bears forced to search for food in the garbage

Due to climate change, polar bears are forced to change their habits. It is becoming increasingly easy to spot them not only in areas where seabirds nest, but also in human-populated areas where they go to rummage in landfills in hopes of finding food.

A few months ago, images from Siberia that showed ten polar bears surrounding a garbage truck and then boarding it and feeding on waste went around the web. Unfortunately, these are no longer isolated cases, but episodes we have to get used to. Cases of cannibalism among polar bears are also increasingly frequent, as they now have less food available due to the climate crisis.

Fonte: The Royal Society/Vanderbilt University