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Help develop a Bird ID tool!

Common Merganser

Mergus merganser ORDER: ANSERIFORMES FAMILY: ANATIDAE

IUCN Conservation Status: Least Concern

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.

Range Map Help

Common Merganser Range Map
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Field MarksHelp

  • Breeding male
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    Common Merganser

    Breeding male
    • Large, slender-billed diving duck
    • All dark, glossy-green head
    • Long, bright orange-red serrated bill with hook at tip
    • Bright white body with black back
    • © Raymond Lee, Edmonton, Alberta, Canada, April 2012
  • Adult female
    Zoom In

    Common Merganser

    Adult female
    • Large, heavy-bodied diving duck
    • Long, slender orange-red bill
    • Chestnut brown head with white chin patch
    • Slaty gray body
    • © Ken Phenicle Jr., San Jose, California, December 2011
  • Breeding male
    Zoom In

    Common Merganser

    Breeding male
    • Large, slender-billed diving duck
    • All dark head usually shows glossy green sheen
    • Long, serrated bright red/orange bill
    • Bright white body with black back and grayer rump
    • © Simon Richards, Vancouver, British Columbia, Canada, January 2012
  • Adult female
    Zoom In

    Common Merganser

    Adult female
    • Heavy-bodied diving duck with long, thin red bill
    • Dark chestnut brown head, sometimes with shaggy tufts on nape
    • White chin patch
    • Slaty gray body
    • © Ron Kube, Calgary , Alberta, Canada, April 2009
  • Breeding male
    Zoom In

    Common Merganser

    Breeding male
    • Large, stocky, mostly bright-white diving duck
    • Slender, serrated red bill with hook at tip
    • Solid dark head shows green iridescence in sunlight
    • Grayer rump and dark back
    • © Bill Thompson, Anchorage, Alaska, November 2010
  • Adult female with chicks
    Zoom In

    Common Merganser

    Adult female with chicks
    • Breeding females often seen with large groups of chicks in tow
    • Female shows dark chestnut head with white chin patch
    • Chicks show dark bodies and chestnut crowns with contrasting white throats
    • © Christopher L. Wood, Minnesota, June 2008

Similar Species

  • Breeding male
    Zoom In

    Red-breasted Merganser

    Breeding male
    • Similar to Common Merganser but smaller and more slender-bodied
    • Longer, thinner orange bill
    • Shaggy crest
    • Gray flanks and rusty patch on breast
    • © Steve Zamek, San Francisco Bay Area, California, February 2012
  • Adult female
    Zoom In

    Red-breasted Merganser

    Adult female
    • Similar to female Common Merganser but with longer, paler bill
    • Paler buffy head with no contrasting chin patch
    • Wispier, shaggier crest
    • © Larry McGahey, Seney, Michigan, October 2011
  • Nonbreeding adult
    Zoom In

    Common Loon

    Nonbreeding adult
    • Larger and darker than Common Merganser
    • Thicker, dagger-like bill
    • White from face down to breast
    • © Bill Thompson, Provincetown, Massachusetts, November 2011
  • Breeding male
    Zoom In

    Mallard

    Breeding male
    • Smaller and more compact than Common Merganser
    • Bright yellow, spatulate bill
    • Chestnut breast
    • Silvery-gray flanks
    • © Cdbtx, Lake Kayak, Washington, November 2008

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.