(Credit: U. S. Geological Survey)

Common Merganser - Mergus merganser

Identification Tips:

  1. Length: 18 inches Wingspan: 37 inches
  2. Large, sleek diving duck
  3. Long, pointed bill with serrated edges
  4. Red bill is thick at base, tapering towards tip
  5. Sleek, tapered crest, more obvious on females than on males
  6. Brown eye
  7. White secondaries
  8. Immature similar to adult female, often with a less-distinct chin patch

Adult male:

  1. Greenish-black head and upper neck
  2. White breast, flanks and belly
  3. Black back and upperwing coverts with white scapulars
  4. White secondary coverts crossed with indistinct dark bar
  5. Alternate plumage worn from fall through early summer
  6. Male in basic eclipse plumage similar to adult female

Adult female:

  1. Red-brown head meets pale breast in crisp line of division
  2. Well-defined white chin
  3. White breast and belly
  4. Pale gray body plumage

Similar species:

Adult male in alternate plumage is somewhat similar to male Red-breasted Merganser but has white breast and flanks, and a less obvious crest. Female, immature and eclipse male distinguished from similarly-plumaged Red-breasted Mergansers by sharply-defined chin, reddish head contrasting with white breast, paler gray plumage, sleeker crest and larger bill. In winter, Common Mergansers, unlike Red-breasted Mergansers, are generally found in freshwater habitats.