Accidental scratches..remedy?

No need for a rotary especially if OP is not experience with one. An orbital will get that out without using a rotary. Least aggressive method first.

 

Absolutely Do not take a wool pad on a rotary to that.

 

There could very well have been seeds or near-microscopic seed fragments in the bird shit. And then when you wipe that with a towel the particles scratch the paint. Never use much pressure when wiping bird shit.

 

It hard to get the bird to stay still while you wipe

 

If you know what your doing there is no problem. I usually buff car with a rotary polisher and a wool pad first . Even black cars.

 

True but if OP did this wiping bird poop probably not experienced with a rotary.

 

This is what I've been suspecting all along.