What next? Hollywood pigeons are being put on birth control to stem their population. The birth control agent will be put in rooftop feeders and will interfere with egg development. I assume only pigeons, starlings, and house sparrows feed from these feeders and no native birds would ever try to eat from them. I also assume that this agent can't be passed to a predator like say a Peregrine Falcon who dines on pigeons. Let's hope my assumptions are true.