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common merganser

common merganser (Mergus merganser) [female]
Photo provided by SteveByland/

common merganser (Mergus merganser) [male]
Photo provided by SteveByland/

Features and Behaviors

The common merganser averages 22 to 27 inches in length (tail tip to bill tip in preserved specimen). The male has green head feathers and black back feathers and white feathers elsewhere. The female has gray feathers with a crest of orange-red head feathers and white chest feathers. The bill and feet are red in both sexes. Three of the toes are webbed to help with swimming. The bill is narrow and pointed. Toothlike structures are present along the edge of the lower one-half of the bill.

The common merganser is a common migrant and winter resident in Illinois. It may be seen around ponds, sewage lagoons, large rivers and lakes. The male produces a croaking sound, while the female makes a “karrrr” sound. This bird migrates during the day. Spring migration into Illinois begins in April. Nesting takes place in Canada and the northern United States. The nest is located in a tree cavity or in a hole in a bank or cliff. Six to 17, tan or dull white eggs are deposited by the female, and she incubates them for the entire 28-day period. Fall migrants begin arriving in mid-November. Mergansers are excellent divers and work under water in teams to catch the small fishes that make up their diet.

Illinois Range


Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae

Illinois Status: common, native