Dr Eric Tan’s was in Japan in March 2011 when he photographed this male Black Scoter (Melanitta nigra), also known as American Scoter in Nemuro, Hokkaidō.
Note that the Black Scoter has a mollusc clamped between its mandibles. It is reported that the bird swallows it whole. The powerful muscles of the gizzard crush the shell, pieces of which may be retained to help in the grinding of the food it takes.
Scoters are dark sea-ducks that spend most of the year in large flocks on the ocean. Their main food when at sea is mussels and other bivalves, crustaceans, marine worms, sea urchins, aquatic insects, small fish and some plant material.
This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.