There are many products on the market designed to try and get rid of nuisance birds, however, the one that works is the one mother nature herself created.  Predator vs. prey is the only sure way to get rid of your problem.  Birds such as pigeons get used to loud noises and shiny things blowing in the wind.  Fake owls only make for a great roosting spot and other devices simply deteriorate with time and the elements.  If you want results, take a look at the way things work in the wild and duplicate it.  This is what we do.  The introduction of raptors to an area with nuisance birds reprograms those birds and makes them understand that where they are currently is not the place they want to be.  Just isn't good for longevity!