Common Merganser (Mergus merganser)

County List:

Rule:

Forested or Mixed Forested/Nonforested Landscapes

Nesting and Foraging Habitats are Adjacent during the early breeding season.

Nesting Habitat: 
      (Swamp Hardwoods (Lg Saw or Uneven)) 
      or (Balsam Poplar&Swamp Aspen&Swamp Birch (Lg Saw or Uneven)) 
      or (Any Lowland Mixed (Lg Saw or Uneven))
   containing: (Snags or Living Cavity Trees or Man-made Structure - nest box) 
   adjacent to: (Lake or Pond or River)

Foraging Habitat:
      (Lake or Pond or River)

Habitat List:

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Literature:

Habitat: Nest site availability, food supply, and disturbance levels are the primary determinants of Common Merganser breeding habitat. Because females usually nest in tree cavities, the species prefers secluded wooded streams and inland lakes bordered by forest. However, breeding pairs are also relatively common along Michigan's Great Lakes shorelines, where holes or small caves in cliffs provide nest sites. Females will also accept nest boxes located in suitable habitat.

Although Common Mergansers usually hunt by sight and, therefore, prefer clear water for feeding, water transparency is probably not limiting. In turbulent or turbid waters, birds switch from a visual to a tactile search method and detect prey by probing crevices. The Common Merganser's diet consist almost exclusively of fish; individual diets reflect local availability rather than a preference for certain species. The abundance of foraging fish appears to be the only limiting factor for feeding habitat.

Habitat: Breeding: Clear water ponds, lakes and rivers with forested shorelines.

Special Habitat Requirements: Clear water for visibility while feeding. Large trees (minimum diameter 20 inches) with cavities for nesting. Little or no human disturbance.

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.

Diet: Mostly fish. Eats a wide variety of fish; also will eat mussels, shrimp, salamanders, rarely plant material. Adult male may swallow fish more than 1 foot long. Young ducklings eat mostly aquatic insects.

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.