When I was younger, I used to throw bread into the street and let oncoming traffic take care of them. But after a high school trip to Washington D.C., where I dispatched about fifty pigeons with this method with one piece of bread, one of my teachers and a local police officer explained to me why this was not a good or safe thing to do. Needless to say I do not use nor do I condone this method any longer.
Maybe I can think of a safer way to eliminate several pigeons at one time. Perhaps something involving mayonnaise.