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Common Merganser

The common merganser (*Mergus merganser*) is a large fish-eating diving duck found across northern North America, Europe, and Asia.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The common merganser (Mergus merganser) is a large fish-eating diving duck found across northern North America, Europe, and Asia. It is also called the goosander in Eurasia. The species is known for its slender serrated bill, strong swimming ability, and breeding in tree cavities or other cavities near freshwater.

Identification

The species has a long, streamlined body and a narrow bill with toothlike edges. Adult males are mostly white with a dark green head, while females are gray with a reddish or cinnamon head and a short crest.

Habitat and range

Common mergansers occur across the northern hemisphere, including North America, Europe, and Asia. They are associated with freshwater lakes and rivers, often in wooded or forested landscapes.

Diet and feeding

The species feeds mainly on fish but may also take other aquatic animals. Its serrated bill helps it grip slippery prey underwater.

Breeding and nesting

Common mergansers nest in tree cavities, cliff holes, bank cavities, or similar sheltered sites near water. Females lay and incubate the eggs and raise the ducklings after hatching.

Conservation

The species is generally considered widespread and not globally threatened. Its conservation status is assessed as Least Concern.

Key facts

  • The common merganser is one of the largest ducks in North America.
  • Males have a white body and dark green head; females are gray with a reddish head.
  • It is a specialized fish eater with a serrated bill.
  • It breeds in cavities near water, including tree holes and cliff crevices.
  • The species is widespread across Canada and the northern hemisphere.
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Canadian context

The common merganser breeds widely across Canada, especially in boreal forest rivers and lakes, and is a familiar waterbird for Canadian birdwatchers.

Frequently asked questions

What is a common merganser?
A common merganser is a large diving duck, scientifically named Mergus merganser, that feeds mainly on fish and lives near freshwater.
What is another name for the common merganser?
In Eurasia, it is commonly called the goosander.
What does a common merganser eat?
It eats mostly fish, but it may also consume other aquatic animals such as insects, crustaceans, molluscs, frogs, and worms.
Where does the common merganser live?
It lives on rivers, lakes, and shorelines across North America, Europe, and Asia, especially in forested areas.
How can you identify a male common merganser?
A male has a white body, dark green head, and a slender red bill.
Is the common merganser rare?
No. It is widely distributed and is listed as Least Concern.

References

  1. Cornell Lab of Ornithology — https://www.allaboutbirds.org/guide/Common_Merganser/overview
    Supports: Identification, appearance, and general overview
  2. Audubon — https://www.audubon.org/field-guide/bird/common-merganser
    Supports: Diet and freshwater habitat
  3. Ducks Unlimited — https://www.ducks.org/hunting/waterfowl-id/common-merganser
    Supports: Range and breeding distribution in North America
  4. NHPBS NatureWorks — https://www.nhpbs.org/animals/common-merganser/
    Supports: Size, range, and habitat
  5. Wikipedia — https://en.wikipedia.org/wiki/Common_merganser
    Supports: Scientific name, alternate name, nesting, and broad range