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Common Merganser

Mergus merganser ORDER: ANSERIFORMES FAMILY: ANATIDAE

IUCN Conservation Status: Least Concern

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A large diving duck with a long thin bill, the Common Merganser is found along large lakes and rivers across the northern hemisphere. The long bill has toothy projections along its edges that help the duck hold onto its slippery fish prey.

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Appearance

Ducks
Ducks
Typical Voice

Adult Description

  • Large, slender diving duck.
  • Long, thin, orange bill.
  • White patches in wing visible in flight.
  • Male with bright white sides and iridescent green head.

Male Description

Breeding (Alternate) Plumage: Head iridescent greenish black. Neck, underparts, and sides white. Back and tail gray. Black line along sides of back. Outer part of wings black. Bill scarlet-orange.
Nonbreeding (Basic) Plumage: Head rusty brown with short, ragged crest. Chin white. Breast, back, wings, and tail slaty gray. Belly and flanks white. Bill scarlet-orange. White patch in wing visible in flight. Like female, except crest on head may be shorter and wing has larger white patch.

Female Description

Head rusty brown with short, ragged crest. Chin white. Breast, back, wings, and tail slaty gray. Belly and flanks white. Bill scarlet-orange. White patch in wing visible in flight.

Immature Description

Immature resembles adult female.

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Common Merganser Range Map
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Similar Species

  • Red-breasted Merganser male has shaggy crest, reddish dark chest, gray sides, and red eyes. Female is more dirty looking, with duller brown head that fades gradually into dingy breast, lacks distinct white chin, and has a longer crest.
  • Male Mallard also has green head, but has a dark chest, lacks white on the body, and does not dive after fish.
  • Winter loons can look similar, but generally have thicker bills, more white in the face, and lack sharply demarcated dark head.