The streets of a quiet Swedish city have an unlikely clean-up crew. They do not wear uniforms. They do not carry brooms. They arrive on black wings, tilt their clever heads, and pick up discarded cigarette butts one by one. What looks like a scene from a strange cartoon plays out for real in Södertälje, where wild crows have learned to trade trash for snacks and, in the process, could reduce street cleaning costs in a remarkable way.
A City Buried in Cigarette Butts
Cigarette butts cause a huge problem in Sweden. Smokers drop them everywhere, from pavements to public squares, leaving behind a mess that cities struggle to control. Research from the Keep Sweden Tidy Foundation estimates that more than one billion cigarette butts litter Swedish streets every year. That single type of waste makes up around 62 percent of all street litter across the country.
For Södertälje, a city near Stockholm, the cost of fighting this mess runs high. The municipality spends about 20 million Swedish kronor every year on street cleaning alone. A significant portion of that money goes toward collecting cigarette butts, which cost far more to remove than most people expect.
The Unusual Idea That Turned Heads
Christian Günther-Hanssen looked at the problem and questioned whether humans alone could fix it. As the founder of a Swedish startup called Corvid Cleaning, he believed nature already offered skilled workers ready for the task. Crows, famous for sharp memories and problem-solving skills, stood out.
Around 2022, his team launched a pilot project built on a bold idea. Wild crows would collect discarded cigarette butts and drop them into a custom-built machine placed around the city. The machine identified cigarette butts and released a small food reward, usually peanuts or seeds. The birds could eat the reward straight away or carry it off to store or share.
No cages were used. No forced training took place. The crows joined the project by choice.
How the Crows Learned the Trade
The system relied on trial and reward. Through repeated interaction, the crows learned that placing cigarette butts into the machines led to food. Over time, the machines were designed to recognise cigarette butts specifically, reinforcing the behaviour Corvid Cleaning wanted to encourage.
The crows quickly learned which items paid off.
New Caledonian crows, among the smartest birds on Earth, took to the task with ease. Research often compares their reasoning skills to those of a seven-year-old child. They learn fast, remember patterns, and copy each other’s behaviour. Their social learning allowed the new habit to spread among the flock without human involvement.
The birds also showed careful handling. Their precise beaks lowered the risk of swallowing harmful rubbish by mistake, easing some safety concerns raised early in the project.
Counting the Cost of Cleverness
Picking up a single cigarette butt can cost a city anywhere from 80 öre to two kronor when humans do the work. Günther-Hanssen estimated that crows could lower that cost to about 20 öre per butt. If the approach were scaled up successfully, the savings could reach as high as 75 percent of the costs currently spent on picking up cigarette butts.
These figures remain estimates, not proven results. The project never moved beyond its pilot stage. Even so, the numbers caught public attention. A group of wild birds, working for snacks, showed the potential to undercut machines and manual labour.
Praise, Curiosity, and Concern
The project sparked wide attention online, especially after videos and reports resurfaced on social media. Many praised the idea as clever, playful, and environmentally minded. Others raised concerns about the birds’ health. Cigarette butts contain toxic chemicals, and critics worried about long-term exposure.
Corvid Cleaning responded by stressing that the crows participated voluntarily and that the team monitored their well-being throughout the pilot. City officials also kept a close watch, knowing any expansion would depend on funding, safety, and clear results.
Waste experts involved in the trial admitted the project highlighted an uncomfortable truth. Teaching crows to pick up cigarette butts proved easier than teaching people not to throw them on the ground.
A Glimpse of a Stranger Future
For now, the crow-powered clean-up remains a fascinating experiment rather than a city-wide solution. Corvid Cleaning has no major public presence, no official website, and no confirmed plans to expand beyond the pilot.
Still, the image lingers. On a quiet street, a black-feathered cleaner hops along the pavement, lifts a cigarette butt, and flies off to trade it for a peanut. It feels unbelievable, yet it happened. Sometimes, the world’s strangest ideas appear not in laboratories or offices, but perched on a lamppost, watching and waiting.
