Nigel is spot on regarding initial auto AF. This really serves no purpose whatsoever, as the camera will lock on to the first thing it sees. This is what Gary Fong did in his videos when he set out prove the MK11s focussing was rubbish.
I would suggest you stay initially with case 1 and expanded focus point then pan with the birds.
If you really want to use the full 65 point focus then make sure you set the initial focus point manually. I would also suggest that you configue the camera for back button focus.
I'm in an hell of a rush this morning, but later on today I will go into more detail if neccesary and provide a couple of links that will help you regarding the MK11s focusing capabilities.
Two weeks ago I was at the local motorcycle beach racing. I tried out the 10fps with auto tracking, but with initial focus being set manually, all frames were perfectly focused and locked on to my selected target. The only problem I've had since receiving the camera end of October was self inflicted.
Not sure if my problem was an age thing or not, but used similar shutter speeds as I would have done with the 7D, resulting a little camera shake. Since using much faster shutter speeds I've not had any problem.