I used 'One shot' instead of AI Servo for the focus, so instead of re-focusing for each shot, it kept the focal length from the original shot... I am soooo pissed at myself for doing this, lol. Anyhow, this is a big crop, some of the other pics after a crop just aren't sharp enough....
I'll have a Canon 100-400 on loan with me next year, so hopefully I'll get some even better shots!