PARIS (Reuters) - A French theme park has trained six rooks to pick up cigarette butts and other rubbish dropped by visitors in return for food.

Christophe Gaborit, the head of falconry at the Puy de Fou park in western France, hand-reared the six rooks and trained them to collect garbage 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,” Gaborit was quoted as saying on the theme park’s in-house blog.

The rooks, which belong to the crow family of birds, will receive a nugget of food from a small drawer each time they deposit rubbish in a designated container.

While ‘birdbrain’ has long been a pejorative term used to insult someone’s intelligence, rooks are considered particularly smart. Research has shown hand-reared rooks to be adept at using tools in captivity to get food.

Gaborit said his birds had already tried to dupe him by collecting wood shavings in place of rubbish.

The birds will embark on their cleaning duties in the coming days.