Friday, March 29, 2013

Red-breasted Merganser

We are just back from a quick trip to Northern Virginia. One of the birding highlights was finding courting Red-breasted Mergansers at the Riverbend Park run by Fairfax County. This 400 acre preserve lies upriver, on the Potomac River, from the Great Falls National Park. Unlike the federal park, this county park does not charge admission.
The two male mergansers in the upper photo appear to be displaying Sprint behaviors. Here the birds rush along the water to create waves in the water. This behavior allows the males to approach the females. In the second photo, you can see the males were successful. Often females lower their bills towards the water in order to incite male courtship.
Male displays often involve several males and one female. Here the males are showing a Salute Behavior, indicating their interest in the female. Their white neck patches and white backs are especially evident. Their tails are often dropped downward. Males regularly synchronize this behavior.
Females, on the other hand, are not very active participants in these displays. The female in the last photo appears to be stretching, a comfort movement used to keep feathers dry and properly arranged. My source for this ethology is Titman (1999).

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