Red-breasted merganser Mergus serrator

Identification Tips:

• Length: 16 inches Wingspan: 33 inches
• Large, sleek diving duck
• Long, pointed bill with serrated edges
• Thin, red bill seems evenly tapered throughout length
• Shaggy crest obvious in both sexes
• Red eye
• White secondaries
• Immature similar to adult female

Adult male:

• Greenish-black head
• White neck
• Reddish breast with dark streaks, bordered on sides by black-and-white patch
• Gray flanks, tail, rump and uppertail coverts
• Black back
• White belly
• White secondary coverts
• Alternate plumage worn from fall through early summer
• Male in basic eclipse plumage like adult female

Adult female:

• Red-brown head, paler on throat, but without well-defined chin
• Red-brown head fades evenly to paler breast
• Gray and white breast and belly
• Gray-brown body plumage

Similar species:

Adult male in alternate plumage is similar to male Common Merganser but has reddish breast and gray flanks. Female, immature and eclipse male distinguished from similarly-plumaged Common Mergansers by lack of sharply-defined chin and lack of sharp contrast between reddish head and white breast, and by darker gray plumage, spikier crest, and slimmer bill. In winter, Red-breasted Mergansers are more likely to be found in saltwater habitats than are Common Mergansers.

Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.