I was excited when I went to my local location last May to see what I could find to photograph and discovered 20 Great Blue Herons hanging out. They were flying all around so I got the opportunity to take some flight shots. I liked this one but thought I would post it to see what everyone else thought.
Canon EOS 50D with 600mm f/4 L IS
ISO 200 f/6.3 1/800 sec
dynamic pose, well exposed, sharp on head, toe dragging great.
I wish the head didn't merge with the body, so it was more distinct.
Just as a general observation, I would bump the ISO up for BIF shots. I find I need 1/1000 as minimum for reliably sharp BIFs on large birds, and higher on the little rockets.