Traffic Noises Impact Baby Birds' Development and Mortality Risk, New Study Shows
Michelle Milliken
Human-caused noises can impact animals. For example, birds’ behavior has been found to change significantly on nights when fireworks are set off. What about before eggs are even hatched, though? New research shows noises can even be damaging then.
Researchers at Deakin University in Australia and Doñana Biological Station in Spain recently investigated both the short- and long-term impacts of environmental noises on young birds during incubation and nesting. Their findings, published in the journal Science, show that, when exposed to traffic noise, birds’ mortality, development, and later reproductive success are negatively impacted.
To conduct their study, the researchers played either traffic noises or birdsong to the eggs of the Australian bird the zebra finch. Eggs that were exposed to the former for five days were less apt to hatch, despite otherwise optimal incubation conditions.
Dr. Mylene Mariette, co-lead researcher from the School of Life and Environmental Sciences at Deakin University, explains, “Both traffic noise and song were played at the same moderate amplitude – 65 decibels, which is similar to a conversation level – but something about the acoustic characteristics of the noise caused embryonic death.”
The impacts didn’t stop during the incubation period, either. For nestlings exposed to traffic noises, there were also negative consequences for their growth and physiology. They even showed signs of more severe cellular damage, compared to young that listened to birdsong. The team says this came about following accumulative exposure both in and outside the egg. Once the exposure stopped, these effects weren’t reversed, either.
Though they’d been slower to grow initially and were found to be the same size as their peers a month after exposure stopped, the traffic noise group continued to have issues with their physiology, and their cellular damage was still apparent.
Finally, when it came time for them to reproduce as adults, they had half as many chicks as their peers.
Though the cause for worsened health is unknown, the researchers say their findings are concerning, and these issues may also impact other species.
Dr. Mariette explains, “Whatever the mechanism, an impact of such magnitude in a songbird, is highly concerning.
“We may wonder what impact noise has on species for which embryos unambiguously perceive sounds. Among many other species, including humans, foetuses become responsive to external sounds in the last trimester of gestation.
“This study therefore rings alarm bells about the impact of noise pollution on biodiversity and highlights the urgent need for noise reduction measures, for the benefit of humans and wildlife alike.
“Although many solutions already exist, such as using electric vehicles in cities, maintaining trees and hedges along roads to act as noise barrier, favouring train over truck transport for goods, we should but also keep our city parks and own gardens quiet by avoiding noisy tools, especially leaf blowers.”
