I've got these neighborhood birds that I swear target only my santorin s4. A couple real nice ones on the drivers door and front drivers fender. I've tried washing off with Mothers CA Gold to no avail. While I was successful on getting the dirt off a film remains. Not sure how to describe it, like the clear coat is a bit dull and murky where the birds left me their gifts. After 2 washings it's still there.

What should I use to remove the lovely remains of my friendly birds presents?

How long did you let the "presents" sit on the paint? If the clear coat is etched, it sounds like you left it for a few days in the sun. It shouldn't etch the paint this easily.