I do like this shot, it has a lot of potential. I'm going to download a copy and show you how I'd have cropped it, easier than trying to explain it!
OK here it is...
I cropped it, cloned out the leaf and other misc bits of debris in the water and the very tip of the other cygnet's beak, and what was visible of a swan in the very top left. Remember in advanced editing that cloning is allowed!
Then I did a +10 brightness and +16 contrast over whole pic to make the white swans pop a litle more.
Then I magic lasso'd the cygnet, +10 contrast on him, then with the lasso still on him, did 1 pass with usm to try and make him pop a little more.