Yes to brighter, I'd sharpen heads a touch more, add to the right and subtract from the bottom. All in all, a beautiful image, do wish that leading bird would have been just a bit more aware of the head angle rules.
How special to get them so close together. I wonder whether they are a pair. I was so luck in a few years ago to get a Western Grebe & Clarke's Grebe together in the same frame.
Agree they look a little dark and your image needs some CW rotation. The tips of their beaks should be forming a direct line down to the tips of their beaks on the reflections. Depending on how they look a little lighter, I might like to see their heads sharpened a tad more.