This isn't too bad really, but the sky color is really not helping this bird. A richer bluer sky would really bring out the bird a little more. I think if it were me I'd sacrifice a little with a slightly oversaturated sky to make the bird stand out more. Just a thought....
the bird could be much more sharper, and it has way to much of a central feel to it. It can be difficult capturing birds in flight as you may very well know.