Tried some small bird in flight shots in Spring in 2008. It was difficult at first, but I managed to get quite a few nice shots.

Then I tried small bird in fight shots, and it was 100 times harder, at least. It happens in 1/1000 second, maybe. Both birds have to be in focus, and I can't use flash, .... etc. Finally got around 10 decent small birds in fight shots. This is one of them.