This isn't a great shot, but I was happy with it because I've been having a devil of a time trying to get smaller birds in flight in focus. Finally I had some success last night with focus tracking and AF.C! I was able to track this guy all the way across until he disappeared from view and the majority of shots were in focus. (The light wasn't the greatest, so I had to boost the shadows a lot on this.)
It seems that, for me, the auto-9 setting for focus points works best when trying to shoot BiFs against the sky. I tried with expanded AF and center point and it was just too hard to get the point on the small bird to lock focus. I started having better success when I switched to auto-9 points. However, I don't know if this would work well shooting birds lower to the ground against a cluttered background.
Anyway, baby steps. I'll have to keep at it.
(Edit: I see my Exif got stripped. Taken with DA*300, f/7.1, 1/1000s, ISO 400)