Aggravating blue bird

I've got a Blue Bird that hangs on to the driver side window sill of my Chevy Suburban. The bird will fly into the mirror and go back to the window sill and poop. She did that most of the day yesterday and covered the door with bird poop.
I moved my suburban to the side of my house and covered the mirrors with plastic bags. So the bird goes over to my Toyota truck and does the same thing. So I put plastic bags over the mirrors on the Toyota also.
So, what does the bird do. She sits on top of the plastic bags and poops anyway. :eek: She will fly off when I go outside, but comes right back when I go back inside.
Man, what a delemma.