The Dutch name for the common scoter is actually more appropriate: black sea duck. It is in fact the only true black duck. At least as far as the males go. Females are dark brown.They eat shellfish, which they catch by diving down to the sea bottom. They swallow them whole and break them open with their strong stomach muscles. Common scoters are often seen in large groups along the coast, particularly in the winter. Shellfish fishermen fishing for spisula use the presence of the common scoter to find the spisula banks.