I think it's a brilliant shot. Birds of Prey are entirely about catching and killing other birds and as such you have captured perfectly the essence of the subject. The expression of the sparrow also perfectly supports the story of the shot.
It's also nice and sharp and well posed with 'eye contact' from the Hawk.
Would have been better on a nice mossy rock rather than a mossy felt roof but that's neither here nor there.
Great pic, well shot.