7/24/09

Four days later the Red-breasted Merganser fleet has been reduced from 42 to 36 by predation, including by eagles on Houston's end of the lake.  Houston Snyder photo detail

The photos above and in the center column came with and developed into an interesting discussion.  Terry thought they were grebes, right?  I thought they had more the head shape of mallards, but the photo is not detailed enough to get a close-up and the bill looks a bit too long.  After publishing them here, but without the above repartee, Dan emailed the following:

Merganser Life History:

Females breed in their second year. They usually lay only one clutch per year, with average clutch sizes ranging from 6 to 17. Females will lay their eggs in the nests of other cavity-nesting ducks, leaving their offspring to be incubated and brooded by the "parasitized" female. Incubation lasts from 28 to 35 days, and females brood the young in the nest for about a day after hatching. Once the young leave the nest, females usually take them to large lakes and reservoirs. Brood mixing and adoption is not uncommon in Common Mergansers, but not much is known about how and why these large gangs (>40) may occur. Banding records indicate that the maximum age is about 12 1/2 years for males, and nearly 14 years for females.

Kudos to Dan for the research.  I can't tell if the adult of the flock is a merganser for sure because I can't make out the typical feather tuft on the back of the head (see left column).  But the behaviour he found appears to be species specific, a good test of the truth. Thanks for the great controversy Judy!  Maybe someone will send in a more detailed photo of them.  Comments anyone? - Larry Taylor

Terry consulted her "Duck Guy," who has identified the raft of ducks as being led by a Red-breasted Merganser, the same species in the photo in the left column on this page.  I have gotten permission to use the photos and am going to write up this identification marvel from such a low resolution photo for the National Wildlife Federation web page. - LT

Terry says the amazing identification guy is Bob Winckler, President of the local birding club.  Good job, Bob!