In the first image, though his feet were probably submerged, they're at the very bottom of the frame and appear to be cut off, along with the tip of the tail feathers. It seems like with so much extra room at the top and left of the frame, that could have been avoided.
I really like the second one, though! While I am viewing these on my li'l 8.9" netbook right now, I really don't see anything wrong with the focusing. The exposure and focus look good to me. Well captured!
One of the challenges of nature photography is that you often have very little control over the surroundings, or even composition. Wild animals are going to do what they want and go where they want. Perfect composition and eliminating distracting elements is sometimes impossible, even with cropping. You just have to work with what you're given, and in the second image I think you did that well. I stay away from critiquing things that you have no control over.
I think it's also worth mentioning that I usually have little trouble getting ducks to walk right up to me. They must be bribed, of course. If you're quiet and still, you can lure them with bread. If you can get them within a few feet and give them a few minutes to understand that you mean them no harm, they'll often let you walk in circles around them, allowing you to fire away and have a little bit of control over composition.