This American Kestrel was sitting at the top of a dead tree, facing out towards an open field. I noticed the hummingbird moving all around the kestrel in various locations, but mostly from behind it. So most of the time, it was out of sight of the kestrel. It wasn't buzzing the kestrel. It was just preforming a series of aerobatic maneuvers_but it reminded me of a student making faces behind the teachers back. Unfortunately, since I had the kestrel in focus, the camera's depth of field prevented the hummingbird from being in sharp focus as well.