Probably because birds pee and poop at the same time. The dark speckles in the "poop" are the poop, the white stuff is actually their pee. They don't create urea like we do but uric acid, which is a more highly concentrated form of nitrogen wastes and requires more energy to form, but conserves water. Naturally, the stuff is acidic, so I definitely wouldn't recommend leaving it around on a car's finish... wax protected or not!Secam said:When I got my new black (think hot and baking in the sun) Lexus, I waited a few weeks to have it waxed. During that time a bird pooped on it and the poop sat there for the day while I was at work. It ate right through the clear coat! Three years on and the mark it still there. Moral of the story is, get your vehicle waxed as soon as possible to protect against these sort of things.