The (historically Mergus merganser americanus ) is the North American subspecies of the Common Merganser . It is a large, streamlined diving duck known for its specialized "saw-bill" designed to catch fish. Physical Identification
: Unlike typical ducks with flat bills, they possess a long, narrow, and serrated bill for gripping slippery prey. Diet and Foraging behavior
Mergansers are sexually dimorphic, meaning males and females have distinct appearances.