Damn modern technology. We now have radio controlled birds...
Some really great, clean shots of the bird. That requires a lot of practice.
Your first image is your weakest because the bird converges right on that horizon line but it's actually the one that appeals to me most. It has a strong design element, if only the bird were just above (or below) that line. Consider going through your collection and seeing if you can composite something similar.
Thanks for posting