Common Eider
Somateria mollissima

f16 @ 1/1600s, ISO:1600, Nikon D3S w 500mm and 1.7X tele-extender

"Common Eider," Wikipedia, the free encyclopedia. This species dives for crustaceans and molluscs, with mussels being a favoured food. The eider will eat mussels by swallowing them whole; the shells are then crushed in their gizzard and excreted. When eating a crab, the Eider will remove all of its claws and legs, and then eat the body in a similar fashion.
Cape Cod Canal, Bourne, Massachusetts