A Swedish company is testing a system in which crows are rewarded with food for collecting cigarette butts, sparking controversy regarding the health of the birds.

The Swedish startup Corvid Cleaning has developed a device that rewards crows with food for collecting cigarette butts, a major problem in Sweden, where they account for 62% of street litter.

The device allows birds to insert the butts into a special well, and the system is capable of distinguishing between butts and other objects, thus preventing errors. Thomas Thernstrom, responsible for sanitation in Sodertalje, ironically commented that while crows can be trained to collect butts, people cannot be trained not to throw them. However, researchers warn that crows may be exposed to toxic substances from cigarette filters, such as nicotine and arsenic, requiring further assessments to understand the long-term effects on the health of the birds involved in this project.