It is best to never underestimate a crow. Mounting evidence shows that jet-black birds display intelligence rarely seen in other animals. Corvids have cognitive abilities similar to those of great apes, the ability to count and recognize human faces and even use improvised tools. So it’s understandable that you might not have given it a second thought after recently reading about the Swedish town of Södertälje. According to resurfaced posts on social media, the city located about 20 miles southwest of Stockholm is training crows to clean up all the cigarette butts littering its sidewalks and streets.

But although Södertälje does not actually supervise the experimental public service project, the statement contains a grain of truth. As the debunkers at Snopes.com explain, the idea was presented to local civic leaders a few years ago. In 2022, a behaviorist named Hans Christian Hanssen presented a “Corvid Cleanup” speech during the city’s annual Science Week. The proposed project involved training wild crows to collect cigarette litter and deposit it in specialized bins. These receptacles would then dispense a small amount of seeds as a reward for the birds’ efforts.

Crows trained to collect cigarette butts in Sweden

Several outlets and social media accounts soon caught wind of the story and the accompanying video. There was even an independent research evaluation of the concept published in the Magazine of cases of emerging economies in 2024 promoting Corvid Cleaning’s “potential to revolutionize urban waste management.” But beyond the initial rumor, it does not seem that Hanssen’s proposal has progressed much further. The official commercial company Corvid Cleaners finally filed for bankruptcy in October 2025, although the story itself went viral online just weeks later. Since then, claims that Södertälje is still piloting a crow-based escrow service have periodically resurfaced.

It’s unclear why Corvid Cleaning closed last year, although the 2024 assessment may provide some clues. The study’s authors cited “ethical implications and potential impacts on crow health” among their main concerns, as well as public acceptance of the idea. It’s also not the first case of crows catching cigarettes. In 2018, a historic French theme park made headlines for introducing its own garbage-collecting crows. In the end, it is not necessarily Yeah Humans can train crows to clean up after themselves, but ought They train them to do it.

If nothing else, the online misunderstanding serves as a useful reminder that cigarette waste remains a major health problem for both people and the planet itself. The World Health Organization estimates that humans throw away about 4.5 trillion filters each year, and that number could soon double. Cigarette butts accumulate in populated areas, as well as in more remote waterways, oceans and forests. Once there, they can take decades to completely decompose, while releasing harmful chemicals into the environment. Whether with the help of intelligent crows or not, it is a pollution problem that needs to be addressed.

2025 PopSci Best of what’s new

The 50 most important innovations of the year