Alarmed by how many cigarette butts littered the parks of Amsterdam, two Dutch designers came up with an unusual plan to train crows to pick up the butts and trade them for tasty rewards.
Industrial designers Ruben van der Vleuten and Bob Spikman originally considered using robots to clean the streets of cigarette butts, but they presented a series of difficulties, particularly the complicated programming required to have them vacuuming the buts out of every nook and cranny while trying to avoid bicycles and passers-by. So they turned their attention to one of the most abundant resources of urban areas – birds. Pigeons were the first ones they considered, because they can be found in virtually every city in the world, but a quick search revealed that they aren’t really known for their intelligence, so training them would have been very hard. But the two designers soon found a bird that was both very common around human settlements and much, much smarter – the crow.