Exposure to traffic noise disrupts bird development

A recent study led by Deakin University in Australia has highlighted the significant negative effects of moderate levels of traffic noise on eggs and nesting baby birds, demonstrating that such noise exposure can have lasting detrimental impacts on their development and fitness. 

The study adds to growing concern about noise pollution, which is now recognized as a pervasive environmental problem affecting even the most remote areas of the Earth.

“Human-produced noise has become a part of the world’s environment, and traffic noise in particular is incessant and present globally. Such noise has been shown to alter behavior in a variety of animals, including birds,” noted the researchers.

Noise pollution and developing birds 

The scientists focused on the developmental impacts of noise pollution on wild zebra finch birds. The findings indicate that exposure to traffic noise – common in urban settings – directly affects the growth and fitness of birds, starting from when they are just embryos in the egg. 

In their experiment, the researchers exposed zebra finch eggs and baby birds to recordings of typical traffic noise, songs of their species, or silence.

“Noise pollution is expanding at an unprecedented rate and is increasingly associated with impaired reproduction and development across taxa. However, whether noise sound waves are intrinsically harmful for developing young – or merely disturb parents – and the fitness consequences of early exposure remain unknown,” wrote the study authors.

Impacts of traffic noise on baby birds

The results showed that birds exposed to traffic noise from the egg stage suffered from stunted growth, shorter telomeres, and reduced fitness in adulthood. This suggests that the noise does more than just alter the behaviors of adult birds; it has direct biological effects on developing young.

“Here, by only manipulating the offspring, we show that sole exposure to noise in early life in zebra finches has fitness consequences and causes embryonic death during exposure,” noted the researchers.

“Exposure to pre- and postnatal traffic noise cumulatively impaired nestling growth and physiology and aggravated telomere shortening across life stages until adulthood.”

“Consistent with a long-term somatic impact, early life noise exposure, especially prenatally, decreased individual offspring production throughout adulthood. Our findings suggest that the effects of noise pollution are more pervasive than previously realized.”

Broader study implications 

In a related Perspective article, Hans Slabbekoorn, an expert in acoustic ecology and behavior has emphasized the broader implications of these findings. 

“The study of Meillère et al. on zebra finches reinforces the notion of negative noise impact on chicks as they develop in the egg, an effect that extends to prenatal exposure to noise in other species, including humans,” explained Slabbekoorn. 

“The findings suggest that the acoustic environment of breeding birds in cities and along highways should be better managed, and that the acoustic comfort in hospital environments for pregnant mothers and babies warrants special attention.”

The evidence from this study calls for a critical reassessment of the risks posed by anthropogenic noise and highlights the urgent need for effective noise mitigation strategies to protect wildlife and human health. 

The disruption caused by noise pollution to physiology, development, and reproduction can lead to a lifelong reduction in fitness, underscoring the need for policymakers and conservationists to address this environmental issue more proactively.

More about the impacts of noise pollution on wildlife

Noise pollution significantly affects animals, influencing their behavior, physiology, and even survival across diverse ecosystems. For instance, in marine environments, the noise from ships and industrial activities can interfere with the communication and navigation of species like whales and dolphins, which rely on echolocation to find food, mate, and migrate. This disruption can lead to reduced mating success and sometimes fatal ship strikes.

Even beyond the immediate impacts on communication and stress, noise pollution alters predator-prey dynamics. For example, noise can mask the sounds of predators approaching, leading to higher predation rates in noisy areas. Conversely, some predators exploit this, using human-made noise to sneak up on unsuspecting prey.

On land, birds are particularly vulnerable; noise pollution can mask their songs, which are critical for attracting mates and defending territories. Studies have shown that areas with high noise levels often see changes in bird species composition, with noise-sensitive species declining in numbers.

Additionally, chronic noise can induce stress responses in wildlife, leading to elevated heart rates and impaired immune systems, which diminish their overall fitness.

The study is published in the journal Science.

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