Nature’s birdsong soundtrack is becoming quieter, less varied and potentially contributing to environmental destruction, researchers have found.
A study charted changes over 25 years at more than 200,000 sites in North America and Europe and found that widespread falls in bird numbers had significantly affected humans’ relationship with the natural world.
Birdsong has been identified as a key link between humans and the natural world and this diminishing connection as the power of birdsong reduces could have a dire impact on how humans treat the environment, according to the study in Nature Communications.
Researchers from across Europe created five-minute soundscapes of sites using recordings and data from bird counts to reflect the songs of birds during a particular year on the two continents.
They found “a pervasive loss of acoustic diversity and intensity of soundscapes” which has seen one of the most basic links between humans and nature sent into “chronic decline”, with implications for health and well-being.
Dr Simon Butler, of the University of East Anglia in the UK, said that they had not investigated individual birds but farmland birds have been cut by more than 50 per cent in Europe and grassland species have been hard hit in the US in recent decades.
“I have been working in biodiversity for the last 20 years and everywhere we look we see this large-scale decline in bird populations,” he said.
Dr Butler said some sites had bucked the trend with noisier bird soundscapes and further work will be carried out to find out why that had happened.
A rise in noise pollution has accompanied the decline in birdsong, which could be contributing to the global environmental crisis, said the researchers.
The declining link between humans and birds could lead to a “negative feedback loop, whereby a decline in the quality of nature contact experiences leads to reduced advocacy and financial support for conservation actions”, the study warned.
Half of the world's population now live in cities. Rapid urbanisation, the rise of electronic devices and increasingly sedentary lifestyles have all contributed to reducing humans’ contact with nature — with a knock-on effect for physical health and psychological well-being.
The paper concluded that governments' conservation policies should include protecting natural soundscapes.