Long-tailed Duck
Clangula hyemalis

f8 @ 1/2000s, ISO:800, Nikon D300S w 500mm and 1.4X tele-extender

"Long-tailed Duck," Wikipedia, the free encyclopedia. The female has a brown back and a relatively short pointed tail. In winter, the female's head and neck are white with a dark crown. In summer, the head is dark. Juveniles resemble adult females in autumn plumage, though with a lighter, less distinct cheek patch.
Cambridge Bay, Nunavut, Canada