I have a black S5 with two nice dull patches in the paintwork thanks to our flying friends, it was only on their for 2 hours.

How do i fix it

or cover the whole car in vinyl

I've had this happen to two of my Audi's. Nogaro blue 00 S4, and dove grey 07 S4. I tried the forums, tried the cleaners and waxes and clay baring. What worked was going to a local detailer and having him buff it out... worked every time. Seems some of their droppings are more acidic than others and it actually etches the clear coat. For $20 a buff job, it's well worth it.

Be very careful with just using an abrasive and buffer. Occasionally the bird **** etches right through the clear-coat and trying to buff this out will just leave you with a panel that needs re-painting. Best approach is to get clay and clean the area then measure the thickness of the unharmed area versus the bird **** spot with a paint thickness-guage. If more than 15% loss you definitely can't buff it out and it will take some 2000 Unigrit and an application of new clear-coat then further wet sanding and polishing.
Good luck.

had to have a friend break out the buffer(PC) and Menzerna Super intensive polish. ugh. at least its gone, and it didnt eat through the "protectant", aka FMJ, for the detailers reading this..