The red-breasted merganser (Mergus serrator) is a diving duck, one of the sawbills. The genus name is a Latin word used by Pliny and other Roman authors to refer to an unspecified waterbird, and serrator is a sawyer from Latin serra, "saw". The red-breasted merganser was one of the many bird species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae, where it was given the binomial name Mergus serrator.

Description & appearance

The adult red-breasted merganser is 51–62 cm (20–24 in) long with a 70–86 cm (28–34 in) wingspan. The red-breasted merganser weight ranges from 28.2 to 47.6 oz (800 to 1,350 g).

It has a spiky crest and long thin red bill with serrated edges. The male has a dark head with a green sheen, a white neck with a rusty breast, a black back, and white underparts. Adult females have a rusty head and a grayish body. Juveniles look similar to females, but lack the white collar and have smaller white wing patches.

Voice, singing & call

The call of the female is a rasping prrak prrak, while the male gives a feeble hiccup-and-sneeze display call.

Distribution & habitat

Its breeding habitat is freshwater lakes and rivers across northern North America, Greenland, Europe, and the Palearctic. It nests in sheltered locations on the ground near water. It is migratory and many northern breeders winter in coastal waters further south.

Diet

Red-breasted mergansers dive and swim underwater. They mainly eat small fish, but also aquatic insects, crustaceans, and frogs.

Reproduction

It nests in sheltered locations on the ground near water.