Because acoustic recordings were not made systematically at fixed locations during those 25 years, researchers have developed a method for reconstructing “healthy landscapes” from the past 25 years. They used “citizen science” sources, such as counting data and audio recordings of individual birds (of about a thousand species) from those regions. Those recordings were from zeno singingA global database where anyone can publish recorded bird sounds. For example, researchers reconstruct healthy landscapes for about 200,000 sites each year, fitting each species into the proportion of count data in intact landscapes. Thus they noticed a decreasing trend in the phonemic complexity of the “soundtracks”. In other words: in most areas it has become calmer and less diverse. Fewer birds chirping, fewer species.
Researchers publish their results Tuesday in the scientific journal Nature Connections. In it they refer, among other things, to silent spring, Title book American biologist Rachel Carson outlined the potential consequences of pesticide use on nature in 1962. This scenario appears to be increasingly becoming a reality with this research.
It is known that biodiversity – including among birds – is declining around the world. If there are fewer types and numbers, then it stands to reason that there are also fewer that can be heard. However, the association is not direct, the researchers wrote: “The loss of species such as the skylark or Nightingale, with rich and complex songs, is likely to have a greater impact on the vocal landscape than the loss of corvids or gull species, but it will also depend on the number of Other types are present.
In reconstructing the intact landscape, the researchers looked only at birds. The birds of each species have not been studied, and no inventory has been made of how the sound landscape has changed in each country or location. Other animal species have not been “measured”, but the researchers consider that as biodiversity has decreased, the presence of their noise has also changed and decreased. External factors, such as noise from air movement, automobiles and other human activities, were also not incorporated into the reconstructions.
According to scientists, the importance of research lies, among other things, in the well-being of people and the appreciation of nature. According to scientific studies, the “experience” of nature contributes to this well-being. Bird sounds are an important factor in this, because many people hear birds before and more often than they see them.
Hans Slapikorn, associate professor of auditory ecology and behavior at the University of Leiden, who was not involved in the research, describes it as “a fun and valid way to make birds heard for years.” Whether the reconstructions are accurate in an absolute sense is less important to him: “ if you always use the same method, you’ll still get an accurate representation of trends. You can see a distinct downward trend in the patterns that have emerged over the years, with less variety and a more uniform soundscape of the birdsong.
Slapikorn also mentions the differences between North America and Europe as striking: “Development in Europe appears to have proceeded faster than in America. I can’t judge that. Probably because there are many urban landscapes in areas with poor results. Time and time again, research has shown that traffic noise and light pollution have a significant impact on bird numbers.
