I can't tell you how many times a bird shit on my car the minute after I washed it. I'll wash it and pull it into the garage ASAP but i'm always too late.
Let this soak in for a few seconds, then wipe away. Then follow with spray detailer. This minimizes scratching and residue that bird poop can leave if left on paint too long. I normally sell a dilution of this to my detail customers in the spring for bug season and for bird poop.