Sea ducks are a type of waterfowl that inhabit coastal areas and estuaries. The four solutions to the crossword for the term SEA DUCK are SCOTER (6 letters), EIDER (5 letters), SMEW (4 letters), and COOT (4 letters). SCOTER is a large sea duck with a black head and neck, white patches on its wings, and a stout bill. EIDER is a large sea duck with a thick layer of down feathers and a distinctive black-and-white head pattern. SMEW is a small sea duck with a white body, black head, and red bill. COOT is a medium-sized sea duck with a black head, white bill, and grayish-black body.