Top Photo: Two of six hooded mergansers circle wetlands.

As in every year since I’ve been working at the museum, hooded mergansers have arrived in our wetlands by mid November. This year, six were spotted on the early date of November 9, though only two of them actually dropped in. Four birds were seen making a pass at the museum’s wetlands but continued on elsewhere.

Since that day, they’ve been seen on the 12th and again on the 15th when five males and two females dropped in. Typically the male mergs begin pair-bond displays soon after arrival. One, two or as many as five or more males will encircle, call out and strut in front of what usually is one female merganser until the female decides which of her suitors she favors.

Males in pursuit of a bond.

The pair remain bonded for the duration of the winter. We’re sometimes lucky to see their copulation display later in the season before departing for their breeding grounds. Here’s how I described at least part of that display in another post.

There’s another dance, or display, which I also sometimes see here at the Museum. It involves the male swimming zig-zag circles around the female with quick turns to the left, to the right, and back again. The display also includes frequent side to side head shakes, and what I can best describe as nervous twitching, stretching, preening, and other distraction-type behaviors.

All this bobbing and weaving is apparently solicited by the female stretching out “prostrate” on the water. The prone position triggers the male’s behavior. It’s a signal of readiness. This display can be called the mating or copulatory display, as it terminates in copulation.

The pair pictured below performed this behavior on November 15 in our wetlands.

Turn one way, then the other, strut your stuff…
Finally the male mounts the female. You can see her head just barely above the water’s surface.
After several seconds, they separate, vigorously wash and preen, then act as if nothing had transpired.
Back to normal.

If you want to read the entire post about the copulatory display click here. I recommend you do so. There are much better photos there as well.

The female shown obviously made a quick pair-bond decision on arrival here at the wintering grounds this year, or arrived already paired. There were four other males and one female present besides this pair so there’s sure to be more action.

Drop by and watch for yourself. It’s a fascinating behavior.

In the mean time check out this video shot here at the museum.

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