Big stores with automatic doors have a hard time keeping birds out. I’ve seen them in grocery stores and Home Depots. I don’t know for sure, but I figure they must do fine, or else we wouldn’t see so many there. I see pigeons underground, like some kind of cave bird. We are seeing evolution in progress. Cave birds and store birds. The only kind of bird I’m sure we won’t see, is window banging birds. Or maybe not. All the softheaded birds will die, leaving only hardheaded birds to reproduce.