Polar bears are inefficient predators of seabird eggs

Climate-mediated sea-ice loss is disrupting the foraging ecology of polar bears (Ursus maritimus) across much of their range. As a result, there have been increased reports of polar bears foraging on seabird eggs across parts of their range. Given that polar bears have evolved to hunt seals on ice, they may not be efficient predators of seabird eggs. We investigated bears’ foraging performance on common eider (Somateria mollissima) eggs on Mitivik Island, Nunavut, Canada to test whether bear decision-making heuristics are consistent with expectations of optimal foraging theory. Using aerial-drones, we recorded multiple foraging bouts over eleven days, and found that as clutches were depleted to completion, bears did not exhibit foraging behaviours matched to resource density. Bears visited fewer nests overall as the season progressed, but marginally increased their visitation to nests that were already empty. Bears did not display different movement modes related to nest density, but be...