Oh I know all about this. Get one every few summers- it will just keep battling itself, banging into windows, and crapping everywhere. I am never lucky enough to have one bash its own brains in though lol. You really think they would. I found these scary "beach ball" things that have big, exaggerated eyes on them, and they work well. Looks a bit weird when you see them hanging on the house though. Kinda like Voodoo shit. But that usually still won't deter them completely- they just find another 'target'. The one I had last year found the plastic chrome trim on the lower grille of my Jeep. It spent all summer launching itself into that lol.
Its only the males that do it. The one I had last summer a lot of the time would have its mate sitting there on the ground watching him. Like "Hey babe look how tough I am fighting this dude to keep him away from you".