"The black rump of the male gadwall contrasts sharply with the gray plumage and provides the best field mark on swimming birds ... Both sexes have white inner secondaries that sometimes show as small patches while sitting and that provide diagnostic white specula on the trailing edges of the wings in flight."

The female.

The bird in flight.

Photo taken with a Nikon D90 using a Nikon 400mm, f/5.6

December 16, 2011.