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I am having some trouble with getting a reasonable of in focus shots for BIF. The two shots illustrate some of the types of difficulties I have been experiencing. I had the the Servo speed set to slow for these two particular shots using center point with expansion on. Curious as to how I could change my AF settings to get me a better percentage of in focus shots. (aside from my lack of skill)
f/6.3 ISO 800
Your settings look to be fine, but you need to be certain that you have locked in focus with the center point on the bird before you start shooting, and my guess is that that did not happen. The 7D should be more than capable of doing well with AF in that situation. I have many bursts of 7 or 8 shots of a bird flying straight at the camera with busy backgrounds and ending up with 7 or all 8 of the shots in focus.
In your pictures, I'd be fairly certain that the focus locked on the background. With the relatively small head of the bird, I would not even try to focus on its head. I'd try to lock in focus with the center point on the fat part of the bird's breast, and there still should be enough depth of field to keep the head in focus. Also, as Pixel Perfect suggested, if the amount of contrast is not sufficient to be able to lock in focus on the bird, I would switch to just using the center focus point so as not to allow one of the surrounding points to lock onto the water. Again, though, regardless whether you are just using the center point or the center point expanded to surrounding points, you still need to start by locking the focus in with the center point. Until you have done that, the camera doesn't know what the subject is on which it should be focusing. And, as soon as you sense that you are starting to lose focus, that is when you need to back off of the shutter and re-establish focus lock, again, with the center focus point.
Also, even though I don't think that it is the cause of your out-of-focus shots, my preference is to leave the tracking sensitivity at its default neutral setting. That setting is a double-edged sword. If you reduce that setting, it should theoretically make it less likely that you would lose focus, but it will also make it less likely, if focus is lost, to regain focus. Similarly, if you increase the tracking sensitivity, it can make it more likely that focus will be lost while tracking, but it will also make it more likely that focus will be regained. My experience with multiple 1-series bodies and with the 7D, however, is that this setting is rarely the reason for either success or failure in tracking a moving subject, and, unless there is some specific reason for changing the setting, I leave it at the default.