Your composition is pretty good. I like the focus being on the head, and not including too much other than what's necessary to get your point across. The saturation seems like it might be a little too much, although I guess it's possible that it came out of the camera that way.
Your focus is just about spot on -- try to get it right on the eye always when shooting animals -- which is apparently what you did here, good job. There is a lot of pixelation in the grass in the background. I'm not sure if that's a result of jpg compression or from a bump in saturation, either way, probably not going to be too desireable as a 'stock image'.
Your score seems right on par. 5.4 -- that's pretty good. Good shot and keep shooting!