The Dutch start-up Crowded Cities, founded by Bob Spikman and Ruben van der Vleuten, looks at solving a problem which can be found in most cities: litter, and in particular, cigarette butts. Instead of creating complex machines to do the job, Bob and Ruben looked to the existing ecosystem in cities for a solution.

The Crowbar

Worldwide, around 4,5 trillion cigarettes are dropped on the streets each year. In the Netherlands, this number is around 6 billion.

Cigarette filters take quite some time to degrade, namely around 12 years. So, to clean up this mess, the founders of Crowded Cities turned to crows - intelligent animals that can reach all corners of the city. This is when they came upon the idea of a Crowbar, where crows can exchange cigarettes for food; win-win.

The Crowbar features a funnel, which the crow must drop the cigarette butt into. A camera must then recognise and verify that the object is indeed a cigarette butt. Once the object has been verified, a food dispenser drops a reward onto a tiny table for the crow, reinforcing the cigarette-clearing behaviour.

After this process, the crow will hopefully spread the word to its fellow crows, which, with the promise of a reward, will begin picking up littered cigarette butts. It is, however, not clear whether this will be the case.

Training the crows

Before the crows can use the Crowbar, they need to be trained to associate cigarette butts with food. This is done in a few steps.

Step 1

In order for the crows to associate cigarette butts with food, a tray of food is placed in the machine, next to a cigarette butt.

Step 2

In this step, the crow gets accustomed to the machine and its functions, and the food is only dispensed when the crow arrives.

Step 3

The food is then completely removed, and only the cigarette butt is left. The crow quickly realises that pushing the cigarette into the funnel triggers a reaction from the machine, leaving it with food as its reward.

This step is then repeated until the crow has mastered the idea.

Step 4

In this last step, cigarettes are littered around the machine, as they might be in a city. The crow, having been trained, recognises the cigarettes and its opportunity for a reward, thus spurring it on to clean them up in return for treats.

Inspiration for the Crowbar

The Dutch duo behind the Crowbar was inspired by Joshua Klein, from the USA, who created the Crow Box, which trained crows to deposit coins in exchange for peanuts. His invention is Open Source.

All the parts of the Crowbar are working separately, but they still need to be assembled and tested with crows.