Red-breasted Merganser

Overview

The Red-breasted Merganser is a slender diving duck closely related to the Common Merganser but generally more coastal in its winter distribution. Breeding males show a dark, glossy green head with a shaggy, double-pointed crest, a white collar, and a streaked rusty-orange breast band, along with finely vermiculated gray flanks. Females resemble female Common Mergansers but show a more gradual blending between the reddish-brown head and grayish body, along with a similarly shaggy but less crisp crest.

Feather Identification

• Crest shape: A shaggy, double-pointed crest of feathers extends from the back of the head in both sexes, more disheveled-looking than the smoother crest of the Common Merganser.
• Breast pattern: Males show a streaked rusty-orange breast band, distinct from the plain white breast of the male Common Merganser.
• Flank pattern: Finely vermiculated gray flanks add texture to the male's body feathering, unlike the cleaner white flanks of the Common Merganser.
• Head-neck blending: In females, the boundary between the brownish head and gray body is more gradual and less sharply defined than in female Common Merganser.
• Neck ring: A white collar separates the dark head from the breast in breeding males, a useful additional field mark.

Plumage Notes

Breeding males show a dark green head with a shaggy crest, white neck collar, streaked rusty breast, and finely vermiculated gray flanks. Females have a reddish-brown head blending gradually into a gray body, with a shaggy but less defined crest than the male. Eclipse males resemble females but may retain some darker back feathering. The species undergoes a complete post-breeding molt with a flightless period. Juveniles resemble females, gradually developing full adult male patterning.

Habitat & Range

Red-breasted Mergansers breed across northern forested and tundra-edge regions of North America and Eurasia, nesting on the ground near lakes, rivers, and coastal wetlands. In winter, the species shifts to a strongly coastal distribution, favoring bays, estuaries, and nearshore marine waters more consistently than the more freshwater-associated Common Merganser. The species is migratory, moving between northern breeding areas and temperate coastal wintering grounds.

Behavior & Field Notes

Red-breasted Mergansers dive to catch fish, often pursuing prey cooperatively in small groups along coastlines and estuaries. Nests are built on the ground, typically well hidden in vegetation near water, differing from the tree-cavity nesting of the Common Merganser. The species is fast and agile in flight, often traveling in small, loose groups low over open water. Calls are generally quiet, with soft croaking or grunting notes exchanged mainly during courtship and social interactions.