Pigeons are merely a curiosity for some but can be a real nuisance in large numbers. Pigeon droppings are corrosive and can cause major damage to buildings.
What is more, these birds carry parasites that can infest buildings. Rubber snakes, plastic owls, and aluminum plates are some ploys used to scare them away, but the effect will eventually wear off, as the pigeons realize that they are fake. You can also use repellent gel, a chemical paste that makes treated surfaces heat up the birds' feet when they land . This can ward them off for a good year or two depending on the weather. The last—and best—solution is to install Nixalite, a permanent barrier of stainless steel spikes pointing in all directions that keeps the birds away.
Whatever solution you choose, be it repellent gel or Nixalite, be sure to rid the surface area of any bird waste beforehand.