Find a hawker, or for more fun a falconer, and have them come fly their bird for a while a few times. The nuisance birds will decide to be a nuisance elsewhere.

I recommend a falconer because you might be able to get them to have their bird stoop right over your head. Seeing one of those pass about a foot up going 100 miles an hour is way cool. Though a hawk will get the nuisances cleared just as effectively and the bird isn't as valuable.