This is a craptastic photo from a technical standpoint, but I was so chuffed that I caught the motion I had to post it. The Chickadee in flight was bumped from his position by the fellow in back. They zoom in and out all day long. We need an air traffic controller sometimes!
It is such fun to watch the interaction of some birds - some hold their ground (not always nicely) while others fly off at even the sight of one appearing Like the action you caught - wonder if he bumped his head!