He's right, snakes work. I'm in the billboard business and we are constantly fighting pigeons crapping on everything under the sign. We tried owls and they don't work. Nets work but the PETA folks call when there's a dead pigeon hanging in the net for all the world to see. We went and bought some rubber snakes from Toys R Us and that worked for a long time. We just zip tied the snakes to the cat walk and upper support stringers and the pigeons disappeared. After a while the snakes will colors will fade with the sun and the pigeons will return and peck the eyes out.
I'm not sure if it's pigeons you have but they also make something called crazy corn. Corn soaked in some sort of something that makes them 17ed up for a while after they eat it. Drunk and stupid acting. The other pigeons see it and leave the area. We tried it in a parking lot of a Whole Foods, (bad decision), due to multiple complaints of bird crap. The birds were walking around the parking lot, along with every other racoon and possum in the area, all 17ed up and no one knew why except us. It was hilarious but we decided we didn't want to be on the wrong end of the granola lovers wrath so we quit using it.