In the Swedish town of Södertälje, near the capital Stockholm, crows are being trained to pick up cigarette butts and other litter from the street in exchange for treats.

For every piece of litter collected and brought to a specially designed machine, the wild birds get rewarded with some delicious food.

The project, a large-scale pilot supported by Södertälje as part of a cost-cutting drive, is led by Corvid Cleaning, the start-up company behind this groundbreaking animal-human collaboration against urban littering.

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The company founder Christian Günter-Hanssen told Swedish newswire TT that the birds are "taking part on a voluntary basis," and that crows have been chosen for being particularly smart birds. 

"They are easier to teach and there is also a higher chance of them learning from each other. At the same time, there's a lower risk of them mistakenly eating any rubbish," he told TT.

According to the Keep Sweden Tidy Foundation, more than one billion cigarette butts are left on Sweden's streets each year, representing 62 percent of all litter in the country. 

Picking up these cigarette butts is an expensive task, with the town of Södertälje spending over $2 million on street cleaning. 

Günther-Hanssen is convinced that the crows could save the municipality at least 75 percent of these costs, depending on the success of the scheme and how many birds get involved.

If the pilot project is successful, the scheme could potentially be extended to the whole country.

_{Cover image: SRW/Getty Creative via CFP}