Traffic noise making birds worse at singing, new research finds
Traffic noise making birds worse at singing, research finds - Constant traffic noise interferes with how young birds learn to sing and also weakens their immune system, a new study has found. - Silas Stein/dpa

We've known for decades just how damaging diesel and petrol fumes are for the environment and human health, but the impact of traffic noise pollution on birds is only now emerging.

Young songbirds, just like human infants, are particularly susceptible to noise, and researchers now say roads busy with cars and trucks are making it more difficult for birds to learn to sing.

A new study by Germany's Max Planck Institute for Ornithology says that constant traffic noise is causing "inaccuracies and delays" when young birds learn to sing. It also weakens their immune system.

"Our findings indicate that young songbirds, just like human children, are particularly vulnerable to the effects of noise because of its potential to interfere with learning at a critical developmental stage," said Henrik Brumm, head of the international research project, announcing the findings.

The researchers even believe that traffic noise can alter bird song itself in the long run, as the mistakes birds make when copying other birds in noisy settings will probably accumulate when the songs are passed on, they say.

For the study, published in May, the research team regularly played the songs of adult males to male zebra finch chicks. A group of birds was also exposed to the kind of noise that occurs along busy roads.

The scientists found that the birds from noisy nests had weaker immune responses. Noise is therefore a source of chronic stress in these young birds, they say.

In addition, the chicks' vocal development was severely delayed and their accuracy in learning to sing was significantly lower, they said.

The researchers have been observing zebra finches for some time. In late 2019, they published a study showing that chicks that grew up with road noise were smaller than those from a quiet nesting site.

They were later able to catch up in growth, but long-term consequences cannot be ruled out. Other studies have shown, for example, that birds sing louder and at different times to drown out road noise.