I really like the pose. We have canvas backs at the local bird sanctuary during the winter here in Michigan. I find they are difficult to properly expose as the white back usually blows out. I find with the D300 I have to use at least -2/3 stop and often minus 1 to hold the whites.
Glenn: A beautiful image - as noted above. This drake is performing a "Head-throw" which is a courtship display common in canvasbacks and other diving ducks.