How can i deter feral pigeons?

In the USA private home owners, town or county governments have to hire companies that specialize in deterrent measures, trapping/relocating or disposal by some gruesome means to deal w large populations of pigeons (or non-native European sparrows & starlings). This site might give you ideas of ways to keep them away from open windows: a href="http://birddeterrents.org/" rel="nofollow"http://birddeterrents.org//a