Melanitta nigra; the Common Scoter is a rather large duck. The photo is that of a female. Quite characteristic is the dark-brown top of the head over a greyish neck and lower face. The male, sorry no photo as of yet, is an all black duck with a notch on the beak. They breed along lakes in marshy vegetations. Outside the breeding season they stay on sea, often in the vincinity of the coasts (Europe, NW-Africa).