Okay, I've mentioned this before and I know you all thought I was crazy, but its happened about six or seven times to me now on my IB paint................
1) bird poops while I'm at the park and ride, so it bakes on thouroughly.
2) I finally see the abomination and clean it as gently and completely as possible.
3) I try and try, but the clearcoat appears etched so I go into a deep depression.
4) going on with my life somehow, I wash my MINI several times as usual over the next few weeks.
....and invariably the spot self-heals...or something. It's gone...not a trace. How is that possible!!?!!?!?!?

And these are (one-armed) TEXAS birds!!!!!
Anyway, the moral if this story is to remain hopeful and try a few washes. Remember, I was totally unable to remove these marks at the time.
Hey, maybe I have magic paint.