Great shot, nicely framed. The EXIF data doesn't show if its a RAW file. If it is, and you have the program Photomatix Pro for doing HDR work, you can pull it in as a single image and bring up a subtle increase in feather detail. Most think HDR work is about creating grunge interpretations, not so. You can improve regular images (RAW) keeping them "real".
I like the composition and the heron's pose. A little sharper would be more appealing to me. Are you trying for a moody sunset image? If you're not sold on a dark moody look, a shadows adjustment would open up the bird, loosing much of the darkness without loosing all the mood. Also a slight middle tone dodge on the heron face might add a little interest. I can post an example to illustrate if you'd like.
An easy way to brighten the bird is to make a copy of the red channel, invert and blur it, and copy it to a new layer above the bird. Then change the blend mode of the new layer to overlay. Otherwise, the crop and backlighting looks nice. http://img.photobucket.com/albums/v732/glenngaryglenross/birdPicture_web1.jpg
