Like the oldsquaw, harlequin duck and eiders, scoters are considered sea ducks because they spend a large portion of the year on salt water. Surf scoters get their name from their habit of swimming in or beyond the breaking waves of the ocean surf. The multicolored, clown-like bill of the male surf scoter distinguishes it from other scoter species. Two, white patches, one on the forehead and the other on the back of the head, also sets the male surf scoter apart, and is the most identifiable characteristic when observed from a distance.
Females are less colorful than males.
Delicate white patches on the cheeks below each eye, and another on the nape of the neck are the only light markings on this dark brown bird. For the most part, surf scoters dive to obtain their food. Mussels, small crabs, clams, barnacles and aquatic insects make up the majority of food items consumed, although a small portion of their diet is composed of plant material. In Alaska, large, concentrations of surf scoters can be observed during the early spring, feeding on easily obtained roe deposited by spawning herring. Consequently, the number of young birds entering the population each year is relatively low and highly variable.