I would very easily and c a r e f u l l y wipe the bird poop away, with the microfiber towel, after the degreaser had time to work on the surface but would also wash/rinse the large poop debris away with large amounts of water. Bird poop contains small pieces of gravel which might/could scratch your vehicle finish.
Even with Goo Gone, I had trouble removing a bird stain from my Ranger hood the other day. When all else fails get out the 91% IPA (Isopropyl Alcohol) and be sure to reapply a wax over the stain treated area.