A historical theme park in France plans to use six trained crows to pick up cigarette butts and other rubbish, according to its president.

The birds will be praised with treats every time they successfully bring an item back, the Daily Mail reports

'The goal is not just to clear up, because the visitors are generally careful to keep things clean' but also to show that 'nature itself can teach us to take care of the environment', said Nicolas de Villiers of the Puy du Fou park, in the western Vendee region.

Rooks, a member of the crow family of birds, are considered to be 'particularly intelligent' and in the right circumstances 'like to communicate with humans and establish a relationship through play', Villiers said.

The crows will be encouraged to clean the park by the use of a small box which will deliver a snack of bird food each time the rook places a piece of rubbish inside.

And the crow family is not the only types of birds found to have potential for intelligent roles.

Australian magpies are apparently able to understand what other birds are saying to one another, reported the Guardian.

The wild magpie has learned the meanings of different calls by the noisy miner and essentially eavesdrops to find out which predators are close by, research published by the journal Animal Behaviour in May showed.

The small native honeyeaters have different calls for ground-based and aerial predators, and when recordings of these were played, wild magpies would raise their beaks towards the sky or bow their heads.