I always carry Auto Glym bird wipes in the boot and wipe off straight away.Whatever it is I think you've had some sound advice. I hope it comes off.
You could always contact a local detailer they should be able to professionally try and remove it.
What you are seeing is not actual damage to the paint, so it doesn't need an abrasive solution to sort it.
This is definitely the chemicals from bird poo reacting with the water based paints that are used on cars now. The sun will have heat cycled the area of paint and the lacquer will react.
Use AG super resin polish, its not abrasive, and you will be able to remove this staining. Will need to rewax after though.
Always try and remove contaminants from paint as soon as possible.
So what do you think should the OP use for the windscreen then. I can't think of any poo that would cause that and it makes me think whatever is on the screen and the paintwork doesn't come from an avian source...That's why I said paint.
We store H2SO4 and HCl in glass, and no etching yet...
So what do you think should the OP use for the windscreen then. I can't think of any poo that would cause that and it makes me think whatever is on the screen and the paintwork doesn't come from an avian source...