I hate to sound pessamistic, but I don't know if there is much you can do legally.
At a boat ramp near where I used to live, a flock of several hundred took up residence. They were lighting on cars and trailers, scratching paint with their claws, eating the windshield wipers, door and windshield mouldings (anything rubber like that, but for some reason they didn't seem to bother tires), and ripping the carpet off the boat trailers. Not to mention pooping all over everything that stood still, and a lot of stuff that moved.
The county tried all kinds of things, and nothing worked. They cut down trees, the buzzards moved to others. They hung up shiny things to scare the birds. The birds used them to fix their makeup. They had a fellow who came down every morning throwing fireworks and such. The birds would get up, fly around a bit, then come right back. Yelling at them produced not much more than a couple of hops away from you.
I used to take my bicycle down there and ride the dirt road along the river. I'd have to swerve to go around them, they totally ignored me.
It took the county a couple of years to get the approval to first live trap them and relocate them, and finally to kill a few. I don't know what ever happened there. I moved away, but stopped using the boat ramp long before.
By the way. Someone mentioned cats. Cats were probably at least part of the problem. People dumped cats there. The cats did what cats do, and there were dozens of stray cats around also. People felt sorry for the "poor kitties" and fed the XXXX things. The cats flourished. I don't know if buzzards will kill a cat or not, but I'll promise you those cats never killed a buzzard.
Good luck. You'll need it.