Lesser Scaup
Aythya affinis

f6.7 @ 1/1000s, ISO:1250, Nikon D3S w 500mm and 1.7X teleconverter

"Lesser Scaup," Wikipedia, the free encyclopedia. Adult females (hens) have a white band at the base of the bill, often a lighter ear region, and are otherwise dark brown all over, shading to white on the mid-belly. Drakes in eclipse plumage look similar, but with a very dark head and breast, little or no white on the head and usually some greyish vermiculations on the wings.
Burnaby Lake, British Columbia, Canada