• The wild crows can be trained through a step-by-step learning process.
• The birds can learn to pick up litter by placing it in to a machine which dispenses food.

“They’re wild birds taking part on a voluntary basis,” said Christian Günther-Hanssen, founder of the company behind the method, Corvid Cleaning, to Swedish newswire TT.

The company chose to use crows as they are the most intelligent bird, Günther-Hanssen told TT.

“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 said.

Over a billion cigarette butts are left on Sweden’s streets each year, and they represent 62 percent of all litter, according to the Keep Sweden Tidy Foundation.

Now, the method is ready for large-scale testing. A potential pilot project is being investigated in Södertälje municipality, where crows will help pick up litter.

“It depends on whether we can find a place in Södertälje which will work with the food dispenser, and then if there are opportunities for financing,” Tomas Thernström, waste strategist at Södertälje municipality, told TT.

Similar schemes have been trialled in other countries in the past, such as this story from 2018 about crows helping to keep a French theme park clean and tidy.

Günther-Hanssen believes that the scheme could save the municipality at least 75% of costs involved with picking up cigarette butts, depending on how many the crows collect.