Wild Crows in Sweden Help Clean Up Cigarette Butts

Near Stockholm, in the Swedish city of Södertälje, an unconventional pilot project is underway to tackle one of the most persistent forms of urban litter: cigarette butts. The startup Corvid Cleaning has designed a system in which wild corvids — mainly crows — are rewarded for depositing discarded cigarette filters into a specially built device.

1. Pilot Project in Södertälje

The initiative began locally, with a bird feeder/trash bin installed in the city where crows can voluntarily drop cigarette butts. In return, they receive food as a reward, says Euro Weekly News. The project is being carried out in close cooperation with municipal authorities and environmental organizations.

2. How the System Works

The core of the system is a bespoke machine: when a crow inserts a cigarette butt into a slot, the device detects the object (rejecting leaves or stones) and dispenses a small food reward, such as peanuts. Through this positive reinforcement, the crows learn quickly, leveraging their high cognitive abilities.

3. Potential Savings and Challenges

According to Keep Sweden Tidy Foundation, cigarette butts compose about 62 % of all litter in Sweden. In Södertälje, the annual street-cleaning cost for removing these butts is significant. Günther-Hanssen estimates that using crows could reduce the cost of butt cleanup by up to 75 %.

However, the actual efficacy depends on how many crows participate, how motivated they remain, and whether the behavior is stable over time.

4. Ethics and Bird Health

A key concern is the health risk for the birds: cigarette filters contain toxic chemicals, and handling them may pose a risk to the crows. Corvid Cleaning acknowledges this issue and is carefully testing which types of litter are safe for collection.

Moreover, there is a philosophical debate about sustainability: is it ethical to turn natural foraging behavior into a “job” for animals?

5. Global Attention and Broader Impact

The project has drawn international media coverage. It is a compelling example of leveraging animal intelligence, urban innovation, and environmental problem-solving. While still at the pilot stage, the initiative raises important questions about how humans can harness wildlife cognition — and where the responsibility for waste truly lies.