When the Japanese learn to speak crows to scare away birds

In Japan, as in France, more and more municipalities are complaining about the nuisance caused by colonies of crows which come to attack trash cans and are sometimes aggressive towards humans. To discourage them, researchers have learned to croak.

In Japan, the town hall of one of the districts of Tokyo decided to call on a start-up to get rid of the problem of colonies of crows which plunder trash cans and sometimes attack humans. To dissuade them, a small laboratory, CrowLab, has learned to speak crow.

It was started by researchers at Utsunomiya University. Originally, they sought to better understand the behavior of crows and in particular their language. They therefore recorded the cries of more than 10,000 birds in the towns of the region and tried to associate these croakings with a particular message. Researchers explain that crows have a particularly developed level of communication. After hours and hours of listening, they managed to isolate the croaking of danger, of warning, the cry that crows make when they spot a predator, like a bird of prey or a cat. And they proposed to town halls which are overwhelmed by crows to use this very particular sound.

The cry of danger triggered as soon as a bird approaches

To broadcast it, they built a small box, a sort of mini speaker that can be installed on a pole or against a fence, and they equipped it with an infrared detector. They place it near trash collection areas, where there are always large numbers of crows. In Japan, we do not use large plastic bins like in France; here the bags filled with waste are often placed directly in the street, under a sort of small protective net, just before collection. And so this is where the crows meet to feast. As soon as a bird approaches, the detector spots it and triggers the danger cry. The bird gets scared and flies away straight away.

Adachi City Hall, which is the first in Tokyo to install these anti-crow loudspeakers, says it is delighted with its investment. The destruction of trash cans has decreased considerably in recent months in equipped areas. And the town hall claims that the system even has a positive effect on human behavior. Hearing the croaking, they put their garbage bags better under the protective nets.