Common Merganser
Common Merganser
Mergus merganser
At a Glance
This fish-eating duck is the typical merganser of freshwater lakes. Its flocks are usually small, but these may combine into big concentrations sometimes at large reservoirs. Common Mergansers living along rivers may spend hours resting on rocks or on shore. The British call this bird the 'Goosander.' In some parts of Europe, with artificial nesting sites provided, the species has become a common nesting bird along city waterfronts; this has not yet happened in North America.
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Duck-like Birds, Mergansers
IUCN Status
Least Concern
Habitat
Coasts and Shorelines, Forests and Woodlands, Freshwater Wetlands, Lakes, Ponds, and Rivers, Saltwater Wetlands
Region
Alaska and The North, California, Eastern Canada, Florida, Great Lakes, Mid Atlantic, New England, Northwest, Plains, Rocky Mountains, Southeast, Southwest, Texas, Western Canada
Behavior
Direct Flight, Swimming
Population
1.900.000
Range & Identification
Migration & Range Maps
Migrates mostly in small groups. Adult males, on average, seem to winter farther north than females and young. Migration is late in fall and early in spring.
Description
22-27" (56-69 cm). Male mostly white with black back, green head. Other green-headed ducks (Mallard, Shoveler) have different body pattern and shape. Red bill is thick at base, elongated and narrow toward tip. Female gray, with bright rusty head, sharp white throat. Compare to female Red-breasted Merganser.
Size
About the size of a Heron, About the size of a Mallard or Herring Gull
Color
Black, Gray, Green, Orange, Red, White
Wing Shape
Pointed
Tail Shape
Pointed, Short, Wedge-shaped
Songs and Calls
Low rasping croaks.
Call Pattern
Flat, Simple
Call Type
Croak/Quack, Odd, Rattle
Habitat
Wooded lakes, rivers; in winter, rarely coastal bays. Mainly around fresh water at all seasons. Summer: on shallow but clear rivers and lakes in forested country; avoids dense marshes and muddy waters. Winter: on lakes, large rivers; occasionally on bays along coast.
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Behavior
Eggs
8-11, sometimes 6-13. Pale buff. Females often lay eggs in each others' nests. Incubation is by female only, 30-35 days.
Young
May remain in nest a day or more after hatching; then they climb to cavity entrance and jump to ground. Female tends young birds for several weeks, but young feed themselves; they may survive even if abandoned quite early. Young are capable of flight about 65-70 days after hatching.
Feeding Behavior
forages by diving and swimming underwater, propelled by its feet, stroking with both feet in unison. Finds most food by sight; may swim along surface, dipping head underwater repeatedly until prey is spotted, then diving in pursuit.
Diet
mostly fish. Eats a wide variety of fish; also will eat mussels, shrimp, salamanders, rarely plant material. Adult males may swallow fish more than 1 foot long. Young ducklings eat mostly aquatic insects.
Nesting
Courtship displays of male include swimming very rapidly in circles near female; suddenly stretching neck upward, pointing bill straight up, and giving soft call. Nest site is near water, usually in large tree cavity; also in crevices in rock, in holes under tree roots or undercut banks, or in nest boxes. Occasionally in buildings. Nest of wood chips or debris in cavity, plus lining of down.
Conservation
Conservation Status
May be increasing in Europe; apparently stable in North America.
Climate Threats Facing the Common Merganser
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.