Thursday, December 1, 2011

Gadwall

These two photos, both taken on Cannon Lake near Faribault, Minnesota (27 July 2008 above and 17 March 2009 below) just about cover Gadwall identification. In all plumages, their white wing patches are usually diagnostic--if you can see them. The gray-sided males show black under tail coverts. Erika calls them "Black-assed Ducks." In the first photos, the female, looking a lot like a small female Mallard, might be hard to identify. (Indeed, the duck in the upper left of the lower photo is a Mallard.)

Gadwalls are monogamous. Pairs form as early as November on their wintering grounds in the southern United States and the Mexican coast. Nesting in dense vegetation and often on islands, Gadwalls enjoy high reproductive success. As with many other ducks, pairs break up during incubation, when males join molting flocks. After incubation, the females rear their young in larger lakes. The young are independent ten weeks after hatching (Leschack et. al 1997).

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