Puy du Fou, a French theme park has trained its birds to pick up litter.

The park has already put 6 Rooks to work collecting cigarette butts and other small bits of rubbish. The birds then deposit the litter in a number of strategically placed boxes in return for a food based reward.

Park Manager, Nicolas de Villiers told AFP News, “Rooks are particularly intelligent. They like to communicate with humans and establish a relationship through play.” But keeping the park tidy wasn’t the main motivation for the idea. “The goal is not just to clear up, because the visitors are generally careful to keep things clean. It was also about showing that nature itself can teach us to take care of the environment” Nicolas continued.

Puy du Fou is a historical theme park in Les Epesses right in the heart of the Vendée region of Western France. The park brings more than 2 million visitors every year, making it the second most popular theme park in the country (after Disneyland Paris). The park is unique in the fact that it doesn’t actually have any traditional “rides” or “attractions”. Instead the park presents over 20 different high production historical shows.

Christophe Gaborit, the head of falconry at the Puy du Fou, hand-reared the six Rooks and trained them to collect litter by offering a treat for each piece of rubbish collected. “Rooks are unfairly maligned, classed as a nuisance, but these birds will perform an eco-friendly deed and restore their image.” Christophe also explained that the birds had already tried to out-wit him by returning wood shavings instead.

But they aren’t the first to try this unique idea. In fact, last year Dutch startup Crowded City announced a plan for a similar system called Crowbar, an invention that would attempt to train crows to collect cigarette butts in busy city centers.