this may sound weird but get a plastic owl to set out. bigger the better
A Kroger near me had problems with pigeons (who doesn't) roosting in areas above the main entrance. Of course, the pigeons make quite a mess. The solution? Put these big plastic owls up there to scare the pigeons away.
Every time I looked up, there was a pigeon sitting on the head of a plastic owl, with quite a few droppings on it as well.
I think the owls have been removed and other remedies taken to get rid of the pigeons.