I know someone who uses an ultrasonic bird repeller to keep seagulls off of his pier and it works like a charm. The downside is that you have to listen to the sound of it every 15 minutes or so. It sounds like a rabbit in distress call to me and some people find it quite annoying. More tips on getting rid of pigeons https://homerepairgeek.com/home-pest...f-pigeons.html