Lots of them in the garden this year, more than previous years. I think they hover waiting for a mate or a fight or maybe both. When two of them get entangled they get a bit carried away. These guys sure can move.
I noticed more of them this year as well - they're hover flies. I'm amazed at your patience waiting to observe their extracurricular behaviour - I just see them when I'm hanging clothes on the line! (Guess I have better things to do?)
