Buzz Cut?

I've been having an interesting time watching our colony of Cicada Killer wasps for the last few weeks. Lots of little territorial battles going on around the side gate, all in about 20 square feet. You can walk right through a group of them and they'll completely ignore you- but the ignoring got a little weird when two of them that were chasing each other flew so close to to top of my head I felt the breeze from their wings as they flew by. Note to self: wear hat when observing.