About 6 or 7 years ago in the springtime when most male birds are busy courting the females we had a male eastern cardinal that spent all his time trying to compete for mating rights with his own reflection in our windows. He'd hit all windows HARD on all sides of the house, all hours dawn to dusk, shades drawn or not.
This went on for about 2 weeks until I took him out of the gene pool with a well-placed .22 LR from my trusty Henry that usually dispatches armadillos into the hereafter. I don't normally shoot songbirds, I feed them. It's not like he was going to find a mate anyway, I just made sure his quirk wasn't passed on.
Rest in peace, fella.