Birds roosting on cars

Question
We have two cars parked in our carport as we have done for years and roosting birds have never been a problem.  About a month ago birds started landing on the mirrors of the cars and leaving their nasty droppings on the mirrors and sides of both cars.  Early on it was occurring during the night but now night and day.  I tried moving the cars out from under the carport but nothing changed.
Any suggestions as to what we might do to stop this?

Regards,
Ernest

Answer
It doesn't sound like roosting to me - that's a bunch of birds getting together for the evening. It appears that the birds (I'll bet its Robins, Bluebirds or Cardinals) are setting up territories and see their reflection in your car mirrors or other shiny places. You can try covering the mirrors or putting the car in a garage or getting a car cover. Getting rid of the reflection somehow is the solution. The birds will stop on their own when nesting ends.