I like this picture, but never know where to stand on the "reflection matter" until last week. I found religion, now I stand on the side of the natural image, that being said, well done. There seems to be some unusual patterns in the water-flow behind the bird, or is it just me, well done.
I like the water patterns, pose, and color of your subject. As for the comp, I think I'd actually go more pano on this one cropping off the reflection at the base of the neck.
I would like a little more sharpness on the eye/head and wonder what the strange patterns are in the BG? JC$ noted too above. Eye contact is great, as is the pose and color of the duck. The pano suggestion is not a bad option IMHO. Thanks for sharing. :)
Agree that the head needs a bit of selective sharpening work. For me, this reflection does not work, the crop on the bird itself is too tight, and I would suggest more room on top of the bird and cropping off most of the reflection.
I have always enjoyed your low angles on these guys. They make the image. Super pose, pin sharp feather detail, although I would selectively sharpen the head. I like the light, and agree with Steve's suggestion for the crop at the bottom, but would add a little to the top.