Love this shot Bob. You got some perfect light and an awesome reflection. The contrast with the white birds is beautiful. The only thing I would change is to put the group of birds a little off center to the right.
My first inclination was to say "screw the rule of thirds and off-center subjects" and put the swans dead center. But I really liked the tree reflections so I shifted the birds up a bit. I'll probably crop more off the top, eventurally.