The red-breasted merganser is a duck species that is native to much of the temperate to subarctic Northern Hemisphere. The red breast that gives the species its common name is only displayed by males in breeding plumage. Individuals fly rapidly, and feed by diving from the surface to pursue aquatic animals underwater, using serrated bills to capture slippery fish. They migrate each year from breeding sites on lakes and rivers to their mostly coastal wintering areas, making them the most frequent species in the genus Mergus to frequent saltwater regularly. The worldwide population of this species is stable, though it is threatened in some areas by habitat loss and other factors.
Region
Temperate to subarctic Northern Hemisphere
Typical Environment
Breeds around northern lakes, rivers, and coastal wetlands across North America, Europe, and Asia, then winters mainly along coasts, bays, and estuaries. Prefers clear, open waters where fish are abundant, including sheltered sea inlets and large inland reservoirs. During migration it uses major river corridors and large lakes as stopover sites. In winter it often gathers in loose flocks on nearshore marine waters and tidal estuaries.
Altitude Range
Sea level to 1500 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
A sleek, fish-eating duck, the red-breasted merganser is among the fastest-flying ducks, using rapid wingbeats to skim low over water. Its long, serrated bill helps grip slippery prey, giving rise to the nickname “sawbill.” Males show a dark green, spiky crest and a rusty breast in breeding season, while females are gray-brown with a ragged crest. It frequents saltwater more than other members of its genus, especially in winter.
Temperament
wary and alert, loosely gregarious
Flight Pattern
fast, direct flight with short rapid wingbeats, low over water
Social Behavior
Forms seasonal pairs on breeding grounds and often flocks loosely in migration and winter. Nests on the ground near water, often concealed in vegetation; clutch is lined with down. Ducklings leave the nest soon after hatching and follow the female to feeding areas. Outside breeding, mixed-sex groups forage and roost together along coasts and large lakes.
Migratory Pattern
Seasonal migrant
Song Description
Generally quiet; vocalizations include harsh, rasping calls and grating croaks, especially during courtship. Males give low, buzzy notes and soft wheezy sounds, while females produce rougher, scolding calls.
