I like the silouete against that great background. Not sure about the composition. The bird is facing to the left but the most interesting part of the frame is at the right. The bittern is too much centerd to my taste and I think that the best composition for an image like this one is a vertical format.
Lovely colour and silhouette. I agree with Juan's comments on composition and vertical crop. You may want to ease back on the radius and amount in sharpening as there is a very obvious halo.