Problems are only created by giving birds access to a food supply, but if that supply is removed then the population will disappear. Educating people not to feed pigeons would be the most effective way of controlling pigeons.
Among the popular methods of population reduction are the use of toxicants mixed with grains, and shooting or live trapping. These techniques are labor-intensive and usually prompt an adverse public reaction. Moreover, the removal of a portion of the flock creates a vacuum effect. As birds are then less abundant, there is less competition for food and shelter, and the remaining birds respond by increasing their breeding. Also, birds from other areas move in to exploit the extra food supply. An endless cycle begins with pigeons breeding and repopulating an area just as quickly as they can be killed. Accordingly, it makes more sense to concentrate on prevention and bird proofing.