We had a yellow rump warbler doing the same thing to a neighbor's car down in Florida. Neurotic little thing that kept it up all day long flying up or down and pecking at it's reflection on Larry's car. Jimy might be on to something with the mirror, but I think the owl or hawk figure might be moire effective. Larry didn't have an owl figure, but he did have a Micky Mouse statue, but that didn't work either. Pretty funny though. Maybe some streamers. Your car is too clean and the bird thinks that the reflection is another bird.
