According to a recent study by researchers at the University of Exeter (United Kingdom), jackdaws, a species of crow, modulate their cries to propose and vote on collective decisions.
Depending on the intensity and rhythm of their cries, they manage to determine collectively, as in a democracy, their departure from one perch to another, reports the
BBC
.
To reach this conclusion, cognitive evolution researchers played recordings of their calls to groups of jackdaws.
They then noticed that the thousands of birds gathered reacted in the same way and decided to leave their perch all together in about six minutes.
Moreover, this collective departure does not seem to be caused by the noise pollution, the diffusion of wind noise not causing the group to move.
The impact of noise pollution
According to the scientists, this would therefore be proof that these birds react in a precise way to these cries.
“When a bird calls, it votes or signals that it wants to leave,” analyzes Alex Thornton, professor of cognitive evolution at the University of Exeter and co-lead author of the study.
The objective of this mechanism would be, according to him, to protect the jackdaws against predators and to transmit information between them in order to ensure their sustainability.
These results would also make it possible to better understand the impact of urban and road noise pollution on bird populations.
“If they can't get along and can't agree to leave together, it can have big impacts on their population,” adds Alex Thornton.
In France, according to the Stoc program (temporal monitoring of common birds), 43 bird species have seen their population decline since 1989.
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