We've had Cardinals, blue Jays, Mocking Birds and others set on the mirror and peck at them and leave a terrible mess. Sam with windows and door handles on one vehicle usually on passenger side. they are courting or something. Uncle's home had picture window that claimed many birds. Trees in the yard and light, at the right angle, on a darkned home looked like more forest to the birds.
When they are doing the pecking thing they are determined and won't leave even after being scared off. If they do another will take its place. May have to move where light or shade is a bit different.
