I really like canvas backs, and have taken a lot of their pictures at the local bird santuary. I find it is very easy to toast the whites on the back. I usually find I need to be minus EV to preserve them (D300 also).
I really like the water on the bird, particularly the drop on the tip of the primaries.
There is a thin dark line along the top of the bill where it meets the skull. I am not sure what that is from.
thanks for the comments everyone, I had originally cropped this a bit closer but since I always seem to crop too close I left a bit more in this time, I agree however about trimming top and bottom a bit.
Randy, I just noticed the thin dark line you mentioned,
It's got to be some sheen off the mud or something, wonder if I should clone it out or leave it as is?
re: the line. Since no one else commented on it, it obviously isn't too objectionable, but if it were mine I would take a pass at it. Did you do any highlight recovery on the back whites?