I'm trying to complete all the challenges on the triple decker train, and for Tickle Tiberius the Terrible I need to attract a pigeon in order to stack into it. However, no pigeons will fly to me no matter how many times I relaunch the game, enter/re-enter the room, stack in or out of the soup boys, or bring a different soup boy into the pigeon room. I got the cutscene where a pigeon landed in the soup and was able to use that for the other challenge, but I've run through the pigeon room many times since with soup boys and the pigeons have never once budged. What gives?