Bird songs are disappearing little by little How does this affect the sound landscape of nature?

Because we hear birds more than they see them, their chirps represent one of man's rare connections with nature.

Bird sounds disappear from the sound scene

A research team working on the evolution of the 'vocal scene' in Europe and North America has observed a significant decline in the range of sounds produced by different bird species.

And the writer Fahi ter Minassian says - in a report published by the French newspaper "Le Monde" - that when a city dweller wants to reconnect with nature, the first thing he does is wander through the gardens, countryside and forests, where he enjoys hearing the various sounds of creatures, especially birds. . But this element seems to be disappearing from nature.

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An international working group to determine how the evolution of "sound scenes" in Europe and North America over the past 25 years, in a study published in the journal "Nature Communications" (Nature Communications) on the second of November this.

Bird sounds disappear from the sound sceneA study of the sound scene of birds in 200,000 locations in Europe and North America reached disturbing results

Simon Butler, from the University of East Anglia in the United Kingdom, and his colleagues explained how they combined bird-watching data with vocal recordings to simulate the vital activity of birds over a quarter of a century at 200,000 sites on both continents. Unfortunately, their findings were troubling; The "symphony" of spring turns out to be getting poorer over time.

Half a century ago, it launched bird-watching campaigns that mobilize volunteers who, during the spring, count bird sites in areas of 4 square kilometres. In France, the chronological monitoring program of common birds of the National Museum of Natural History during 32 years managed to monitor about 2,900 sites where birds live.

According to the curator of the National Museum of Natural History Benoit Fontaine, "This long-term work has made it possible to highlight the severe decline in bird numbers, especially in agricultural environments where specialized species such as the ghetto lark are gradually disappearing, and are replaced by other common types of birds, such as the wrachon. familiar (similar to pigeons and slightly larger than them) or titmouse (a family of sparrows)."

Bird sounds disappear from the sound sceneThe time-monitoring program for common birds has monitored over 32 years about 2,900 sites where birds live

Environmental acoustics a new specialty

How do these changes affect the sound landscape of cities and countryside? Because we hear birds more than we see them, their chirping represents one of humans' rare connections with nature.

To answer this question, Simon Butler and his colleagues recorded 25 seconds of each bird's sound of a specific species. Then, they mixed these sounds in order to create synthetic 5-minute audio clips at each location and for each era according to the time of observation. Then they analyzed these audio files using "environmental acoustics" tools.

Created in 2014 in response to requests from the National Museum of Natural History and the University of Urbino (Italy), this modern discipline studies natural sound with the aim of answering questions of an ecological nature such as how bird species evolved in different habitats. The team developed techniques to analyze thousands of hours of bird vocal recordings collected at their experimental sites.

Bird sounds disappear from the sound sceneSimon Butler's group proves that the sound scene has deteriorated in complexity and variety

“One of the processes we do is compress audio files into 1-minute packages to extract up to about 50 distinct audio cues to determine the acoustic richness of a site,” explains Sylvain Hubert, research engineer at the French National Center for Scientific Research at the National Museum of Natural History.

Simon Butler's group has proven that the sound scene has deteriorated in complexity and variety. This study is unique, as Sylvain Hubert believes that "the decline in the number of birds is reflected in the decline in the sounds they produce in nature."