Yes, 'sparring' seems appropriate sinced they seem to use that little beak like a sword.
Yesterday I counted six hummers at the feeders. There were two or more that were going at it pretty hard. I couldn't really tell since they are lightning speed! Several times one or another ended up on the ground. They didn't even care that I was standing there, trying to take a photo which was pretty much impossible as fast as they were moving!
At last two of them stopped to take a drink! (oops-here's the pic)