It's not a bad photograph, but composition seems, well, flat for lack of better word. My first thought is to increase the contrast between the duck and the background, but I don't know how one would do that specifically. Anyway, I think it would make a good computer desktop image.
I like this image - I think the composition is nice, and the colors are great. I think the "flatness" .universeprince picked up on is actually a focus problem. If it were really sharp, I think you would see that difference between the duck and background. That's my guess, anyway.