I made this image a couple weekends ago here in northern Utah... had to bump my iso due to the overcast conditions, but I was happy with the results after processing this one.
40D w/ 400 5.6L
1/1600 f/5.6 iso800
handheld from auto
I would be happy with the result, too, if this were mine, although I might have cropped it differently. Still, looks very good to me. I like the sharpness, the details and the angle the harrier is flying.
I love the dorsal view of the harrier and you did it very well with ISO boosting. In a perfect world, I would prefer not to have the light area in the upper third of the frame. Another round of selective noise reduction to the BG would produce a better result and I would try to boost the saturation of the BG a bit and to warm up the colors a bit. I am sure that this one would also work fine in landscape format :-)
Love the topside detail. I might remove the water/ice up top. I agree with Juan about the horizontal crop, but his saturation boost has more much more color than the actual location does. I would run some NR on the BG too.