Hi Stuart - IMHO - few things combining together here to make this less than ideal..... Bird flying/angled away from you, not the best wing angle and some of those blacks dont look like they have a lot of detail.
Tough one in anything but soft light - but great to practice on :)
I actually like the lighting on this one, and don't mind the lack of detail in the blacks, but I agree with Lance about the bird and the wing angle, and also the cloud (?) behind the bird's head is distracting - although generally I like clouds in an otherwise plain sky to add interest. I also like the placement of the bird in the frame.