Park under a tree lately? Looks like tree sap. Clay bar and some polish should do the trick.

 

Man, I was parked on a little residential street and sitting inside my parked car one time, when I heard this big metal THUD like a rock just hit my hood or something. I was like holy sh*t, wtf was that? I jumped out and looked at the hood and there was this massive bird poop splatter square in the middle of my hood. I then looked up and I saw this big raven/crow looking thing perched on the top of a power pole with its áss hanging over the edge.

 

Heh I had those, but while moving. Hey, how many of you can say they've seen a pidgeon actually sit down on a shiny black beamer to take a poop? I love SF birdies. Hehe