Saturday, June 18, 2011

Common Merganser

This photograph is another result of my spring project to photograph pairs of waterfowl.  These Common Mergansers posed on Circle Lake in Rice County.  Because they tend to winter as far north as they find open water, Common Mergansers are early migrants in Minnesota. They can be found all winter on Lake Superior.

The drake is easy to identify.  The hen can be tricky to separate from the hen Red-breasted Merganser.  One key to identification is the sharp line between her brown head and gray neck.  Other differences include bill and crest shapes. I previously blogged on these subjects.

As the top predator in aquatic food chains, Common Mergansers are sensitive to the presence of pesticides, mercury, and the effects of acid rainfall.  The salmon and trout industry accuse mergansers of preying on these sport fishes. Mergansers, consequently, have been the targets of eradication programs. North American populations, nevertheless, are stable or increasing (Mallory and Metz 1999).

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