they are survivors, that's for sure, and i watch them every day swarming around the valley in large groups, and i can't quite figure out why they are flying around so much but i gather they are good at turning junk into grease and storing the grease so they can run a long time without feeding
it's not for nothing they are almost universal food animals in most of south and eastern europe for poor people, cheap to feed, and decent quality meat, and for bonus points you can use their poop to make gunpowder or fertilise your garden