I have this also on the side of my car,you won`t get rid of it without professional help,i have at least six coats of dodo juice purple haze pro on mine which is suppose to wax and protect.It will be pigeon sh1t which damages the clear coat which stands out more on dark cars.I asked a question on the detailing section but no one could help i now just get it off quick.
wax is not the protection you think, and wax cannot be layered so you may have applied 6 coats, but as you cant layer wax that was 5 coats too much, yeah apply it twice for coverage but more than 2 and nothing is happening.
Bird sh!t is like frickin acid and the wax will not stand up to it, wax after all is a sacrificial layer, be aware the ba5tards eat sand to help them digest so that comes out through their sh!t, so be extra careful when wiping off as it can easily swirl/scratch your car.
I had a car with sh!t on it, and it took a machine for me to get it out. It was hard too.