Hi Rob,
I like the base image. There are a few points that we need to address. The capture angle is too steep, the head angle and eye contact are off. Your perch is a bit over powering and you have uneven lighting; thats why you have shadows on the upper and lower portions of the bird. I modified your composition into a pano crop, opened up the mid-tones, and selective sharpened the eye area, boosted saturation and contrast...see if this presents well with you...:cool:
All covered and no more to add from me. I'm supposed to pay a mockingbird a visit myself. Thanks for sharing your photo and now I know what to look for :)
Rob those guys are common but by no means an easy target. Personally don't have many of them !!! As presented a little fill flash would have made a difference and don't forget to raise the ISO if needed. The D300 does perform well !!!
Everything covered here Rob by everyone else. You exposure looks good and the BG is great. Also like the repost by Gus to pano and a little sharpening of the eye.