I carry a spray bottle in the car with a little vinegar and water to spray and wipe off the presents from the birds. like stated before something in that will almost like crystallize the clear coat and leave you a permanent spot if left for many hours in lots of sun light.

In my driveway I put up one of those plastic owls you buy at walmart in the lawn department, home depot and lowes sells the same thing. I have very little problem with birds in the driveway now. It might be a little awkward setting this up on a tripod every where you go but I guess you could...