Polar bear predatory behaviour toward molting Barnacle Geese and nesting Glaucous Gulls on Spitsbergen

摘要

A polar bear (Ursus maritimus) was observed stalking and chasing a flock of adult flightless barnacle geese (Branta leucopsis) in a coastal bay in Hornsund, southwest Spitsbergen. Before chasing the geese, the polar bear appeared to make use of the cover provided by a rocky pier in order to swim close to them. Immediately after that unsuccessful attempt, the bear plundered a glaucous gull (Larus hyperboreus) nest situated on coastal rock and captured three nestlings. These observations are the first documented instances of a polar bear hunting for barnacle goose and glaucous gull and provide additional evidence of the use of terrestrial prey by polar bears during the season of minimal ice extent.