sawbill

A sawbill is a colloquial term often used to refer to certain species of ducks belonging to the genus Mergus. These ducks are characterized by their long, narrow beaks that are serrated or "toothed" along the edges, giving them a saw-like appearance. This specialized beak is adapted for grasping slippery prey, primarily fish, which they catch by diving.

Sawbills are found in freshwater and saltwater habitats across the Northern Hemisphere. They are skilled swimmers and divers, capable of pursuing fish underwater. Their diet consists mainly of small fish, but they may also consume crustaceans, insects, and aquatic vegetation depending on the species and availability of food.

The most well-known sawbill species include the common merganser (Mergus merganser), red-breasted merganser (Mergus serrator), and hooded merganser (Lophodytes cucullatus), though the hooded merganser is sometimes placed in its own genus. Males typically display more elaborate plumage, especially during the breeding season, while females are generally more uniformly colored, aiding in camouflage. They nest in tree cavities, on the ground, or in rock crevices, often near water. The term "sawbill" is descriptive rather than a formal taxonomic classification, but it effectively distinguishes these fish-eating ducks from other waterfowl.