Sweden has denied reports of a project involving crows that were supposed to clean up cigarette butts
The information currently circulating widely on social media—claiming that crows in the Swedish city of Södertälje are being trained to collect cigarette butts—is not true. According to Popular Science, such a project was indeed proposed several years ago, but it was never implemented.
The idea was presented in 2022 by behavioral scientist Hans Christian Hanssen. It involved training wild crows to collect cigarette butts and drop them into special containers that would dispense seeds to the birds as a reward.
The Corvid Cleaners project attracted significant attention from the media and social media users, and in 2024 it even became the subject of a separate scientific study. However, it did not receive support from the Södertälje city government.
In October 2025, Corvid Cleaners filed for bankruptcy, but reports of the experiment allegedly still being active continue to appear regularly online.
According to Popular Science, researchers cited ethical concerns, the potential impact on the health of crows, and mixed public perception of such an initiative as among the reasons that may have hindered the project’s implementation.
At the same time, the problem of cigarette butts remains a pressing issue. According to estimates by the World Health Organization, approximately 4.5 trillion cigarette filters are discarded worldwide each year; these can take decades to decompose and pollute the environment.
Source: Popular Science.
As a reminder, a team of scientists discovered that crows can “count” aloud. This specific manifestation of numerical literacy has not yet been observed in any species other than humans.
