Male (left) and female (right) Common mergansers swimming the Truckee River in downtown Reno, Dec 2014. Photo: K.McCutcheon.

Male (left) and female (right) Common mergansers swimming the Truckee River in downtown Reno, Dec 2014. Photo: K.Fitzgerald.

Common Merganser 
Mergus merganser
  • A common species of diving duck.
  • Females: brown heads with spiky crest of feathers; grey bodies.
  • Males: resemble females during summer, acquire dark green head-feathers and black-and-white body feathers during fall.
  • Both sexes: Long, narrow orange bills with serrated edges.
Record Observations
Species Description

Common Mergansers are present year-round along the Truckee River and nearby lakes and reservoirs (see eBird database).  Mergansers are diving ducks and feed primarily on fish, but also eat insects, crayfish, frogs, small mammals, birds and plants. The name “merganser” comes from the Latin wordmergus, for “diver” (Beedy et al. 2013).

Mergansers often travel in lines, “follow-the-leader” style, diving, dipping and swimming upstream as they feed.  They seem to avoid humans (or at least me), often crossing the river to avoid close encounters.  This wariness of humans may carry over into their selection of nest sites: The Atlas of the Breeding Birds of Nevada (2007) found Common Merganser nests upstream and downstream of the cities of Reno and Sparks, but found that nests were scarce within the metropolitan area.

Common Mergansers nest in tree cavities or rock crevices near lakes and streams (Beedy et al. 2013). Merganser ducklings stay with their mother for their first 30-50 days, and will sometimes catch a ride on her back while she swims (Mallory & Metz 1999).  After nesting, females and broods normally move downstream to larger lakes or bays.  Female Mergansers will often return to the same nest site for multiple years (Mallory & Metz 1999).

A close relative, the Hooded Merganser (Lophodytes cucullatus) is also present on the Truckee River during late fall, winter and spring.


References & Links

Beedy, Edward C. and Pandolfino, Edward R. 2013. Birds of the Sierra Nevada. Berkeley: University of California Press.

Floyd, Ted; Elphic, Chris; Chisholm, Grant; Mack, Kevin; Elston, Robert; Ammon, Elisabeth; and John Boone.  2007. Atlas of the Breeding Birds of Nevada.  Reno: University of Nevada Press.

Mallory, Mark and Karen Metz. 1999. Common Merganser (Mergus merganser), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Available: http://0-bna.birds.cornell.edu.innopac.library.unr.edu/bna/species/442 doi:10.2173/bna.442

Characteristics

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