Sonja

They're very pretty. Love the photo!

I am afraid Andy, they are winged rodents just like those resident where you are. We actually have no problems with big gulls at all as it is often the case by the sea. The majestic winter guests are far and inbetween seen up close, but often enough circling offshore for a nice maritime atmosphere. They are somewhat shy, break up fish and bird carcasses somehere and free the lake and lonely beaches from that stuff, and they attract a few birder from the backcountry that need a hot meal afterwards.
Black-headed Gulls however are bold as brass and just everywhere around the waterfront, making themselves highly undesirous by those who have everyday to clean up after them, like the server in the restaurants on the promenade.