Background Noise Caused By Humans Makes Bluebirds 'Shout' To Speak Up
It's hard to be heard in a busy world these days, and that's certainly true for birds. Sometimes, they actually have to ‘shout' to be heard over noise produced by human-made activity.
In a recent study, researchers from the University of Exeter examined how bluebirds altered their songs in response to increases in nearby background noise caused by humans, including traffic and other sorts of things.
"Unfortunately, the world is getting so noisy that even the most flexible of species will eventually reach a threshold beyond which they will have difficulty communicating--which will impact their ability to breed successfully," Co-author Dr John Swaddle, from The College of William and Mary, said in a news release.
"When we build roads and airports near human neighbourhoods, we employ noise abatement protocols in an effort to mitigate against the negative impacts of noise pollution. It is time to apply similar caution to conservation, management, and landscaping plans that impact wildlife and their habitats."
Researchers discovered that depending on noise levels, the birds altered their songs immediately, making ‘real-time' adjustments in order to produce songs that were both louder and lower-pitched. The results suggest that they're able to perceive increases in noise and even respond accordingly, quite similar to humans in certain situations.
In this recent study, the study authors recorded songs produced by 32 male bluebirds, analyzing two from each male that were produced during the quietest and loudest period of ambient noise in order to investigate whether males changed their songs between these two conditions.
Findings revealed that, as background noise increased, the male bluebirds produced songs that were typically lower-pitched and louder; this suggests that the birds are able to both perceive and respond to increases in noise, enabling them to produce songs that potential mates or rivals are likely to pick up on.
Researchers are hopeful that future studies could help improve humans' understandings of environmental constraints on animal communications, as well as our awareness regarding what sorts of human modifications can impact animals.
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