Sydney, Nov 11 (Inditop.com) Birds and frogs are raising the volume of their calls to be heard above urban noise, says a new study.
The noise of traffic, machinery and air conditioners may be driving birds with low-pitched songs away from cities, while leading others to raise the pitch of their singing to be heard above the din.
Two studies from the University of Melbourne (UM) have revealed that urban noise is impacting birds in Australia, Europe and North America.
UM botanist Kirsten Parris and zoologist Angela Schneider found that some birds living on Mornington Peninsula roadsides are singing at a higher pitch in traffic noise.
“The grey shrike-thrush can live in narrow strips of woodland next to roads, and this species is changing its song in noisy locations,” says Parris. “But once noise levels get very high, the chance of finding the birds is very small.”
Parris says both cities and roadsides can provide important habitat for many species, if people work to reduce noise levels.
The study suggests reducing traffic noise by changing road surfaces, decreasing traffic speeds, or even re-routing roads during the breeding season when birds are most vulnerable to noise and passing vehicles.
In a second study, zoologists Yang Hu and Goncalo Cardoso studied more than 500 bird species across three continents, and found that those common in cities sang higher than related species that prefer the country life.
“Birds that can’t be heard above the noise of the city may have trouble attracting a mate, maintaining a territory, raising their family, and warning other birds of danger from approaching predators,” Yang says.
Parris and her colleagues recently found that city frogs are also calling at a higher pitch to make themselves heard in traffic noise, says an UM release.
The results have been published in Ecology and Society and Behavioural Ecology.
