This past spring a male bluebird nested in our yard, and in March took a dislike to his image in the mirror of our SUV. He fought the mirror so much we covered the mirrors. He then fought his image in the windows. We rolled down the windows. He then found his rival in the rear window. We placed a plastic owl on top of the vehicle, but that didn't deter him. We finally taped pinwheels onto the mirrors to try to scare him away. He saw his image in those and fought those. Sometimes he would fight the mirror, then turn and bite himself in the back, while leaning backward. He would finally lean so far backward that he would fall off. Between his battles with his image he managed to raise two broods of young. It is now late November with freezing temps, and he is still fighting his image.