I agree they can be a nuisance, but there are other ways to deal with them than killing them, spikes so they cant land, low cost chemical thats sticky and makes life uncomfortable. if you poison them its indiscriminate and the sparrows, martins and other birds will die. I could never understand why they dont make them sterile so they cant produce pidglets or pidglings ) and i dont mean take each one and chop their bits off, put the stuff in food, i know they talked about it in England to use on traffalger square. They eat pigeons here, but i think these are wood pigeons and not your common and garden variety. so no good for pigeon pie.
http://www.bird-x.com/pigeoncontrol/