that war in the barn. That's a different conflict.) It's the Sugar Water War, fought each year by the male hummingbirds whose territoriality is legendary.
This little guy is currently "King of the Mountain."
You can watch a little bit of the zipping here.
Every once in a while they pause and all refresh themselves with sugar water. Which makes it appear to be more of a collegial exercise rather than blood sport.
I hope the ladies are impressed.