I have had a magnificent deep red cardinal pecking away at my back window to the rv for the last year he lands on the ladder run and see's his reflection in the back window of glass and he dives and fights with his reflection and has done so for the last year, that i have been here. Whats worse is when his mate see's him doing this and she comes and joins in it gets pretty loud inside. and if it's not the cardinals it's the titmouse.