I've been taking a lot of images in my backyard around my feeder since my wife broke her hip last month. I would not even want to try getting in flight shots of smaller birds without pre release capture. It can be done, and I have lucked into a few in the past when I didn't have that available, but it requires a lot of fast reflexes, and a ton of luck. The other issue is that they move faster than the AF often can follow. I have seen quite a few that, looking at the image on the camera back, has the rectangle on the bird's eye, but they just aren't sharp. And these are shooting at 1/5000 and 1/6400 sec, so the culprit is likely the electromechanics in the lens isn't able to keep up with the electronics in the camera.