Just a quick posting of my first go last weekend with AI Servo cases and what a challenge I gave myself 
This is far from perfect and the AF struggled but considering the 7D would have failed badly at the same task I am pleased with the way the 5D3 'works' 
Getting the inflight captures was hard of the few where the birds were coming right at me none were in focus the AI servo in the cases I tried could not keep up but considering the size of a Blue Tit maybe not a surprise??? This is a crop of approx. 30% of the frame.
1/2000, f5.6, ISO2000 ~ gotta love the Auto ISO and the (relatively low) noise on this sensor

I took more including a grab shot of a Goose BiF at the local lake and I was well impressed with the way the 5D3 locked on and held focus for the second or so I had the bird in view (again another situation where the 7D was/would be hit & miss...............will PP it and post 'later'.








