Birdsong in the spring would possibly become quieter and less varied in North America and Europe due to declining bird populations, which is bad for ecological diversity and can also have a negative effect on human fitness and well-being.
Natural soundscapes are a way of connecting other people to nature, and it has been shown to benefit our physical and intellectual well-being. The familiar chirps, whistles and croaks of birds are a major component of these soundscapes.
Simon Butler, from the University of East Anglia in Norwich, UK, and colleagues collected bird count knowledge from 202,737 sites in North America and 16,524 sites in Europe, collected between 1996 and 2018, and then the team used knowledge and records from 1067 bird species. extracted from an online knowledge base to reconstruct the most likely bird soundscape to have existed in the year of the site.
For every bird sighted at a site in a given year, the team randomly inserted 25-second clips of their songs into an empty 5-minute sound file. other distances.
“Ideally, it looks like I’ve pulled out a recorder in the box while the user was researching the birds,” Butler says.
The researchers then analyzed the clips with acoustic modeling, which quantified the acoustic characteristics of the songs, adding volume and pitch, and the amount of variation in those properties.
They have noticed a significant decrease in the diversity and intensity of bird songs on both continents over the more than 25 years, meaning the soundscapes of those regions are calmer and less varied. The effects reflect widespread declines in bird populations and biodiversity in North America and Europe over the same period.
Massive increases in human activity, such as agricultural intensification, poor forestry practices, pollutants and urbanization, are partly to blame for these declines. Climate replacement has also affected the distribution of birds in the UK, Butler says.
Birds are used as an indicator of biodiversity fitness in a broad sense, so declining bird populations indicate that other groups, such as amphibians and insects, would possibly be declining as well, he says.
“The time we spend in nature has many physical and intellectual benefits for well-being and health,” Butler says. “If the quality of those reports decreases because our soundscapes change, this suggests that the price and benefits we get from spending time there may simply deteriorate as well. »
Journal reference: Nature Communications, DOI: 10. 1038 / s41467-021-26488-1