Noise generated by humans is affecting the behavior of birds around the world. A large-scale analysis across nearly 40 years of multiple studies points out that the impact of noise on birds ranges from their courtship songs, to their ability to forage and avoid predators, and even interferes with their breeding success rate.
AFP reported on the 11th that past studies of specific bird species have shown that man-made sources of noise — such as airplanes, traffic, and construction — can affect birds in the same way as other wildlife. However, a new study published on the 11th in Proceedings of the Royal Society B offers a broader analysis, examining scientific studies published since 1990 which cover 160 species of birds, in order to determine whether such effects show broader trends.
The analysis found clear evidence that noise pollution has a “ubiquitous” impact on birds’ lives across six continents globally. The research report states, 'We found that noise significantly affects communication, risk behaviors, foraging, aggressiveness, and physiological status. It also strongly affects habitat use and has a marked negative effect on breeding success.'
The study’s lead author, conservation science and policy researcher Dr. Madden from the University of Michigan, says the reason for these impacts is, “because birds rely on acoustic signals to survive.” For example, they use calls to court mates or to warn of predators, and chicks chirp to tell their parents they are hungry. Therefore, birds are particularly prone to being affected by the noise generated by cars, machinery, and urban life. “If loud noise fills the environment, can they still hear the signals from other birds?”
The study found that in some cases, noise interferes with bird courtship behaviors, causing males to alter their courtship songs, or masking the calls between parent birds and their chicks. The reactions of different species also vary: birds that nest close to the ground suffer more reproductive harm from noise, while birds that nest in open sites are more significantly affected in their growth performance; in addition, birds living in urban environments generally have higher levels of stress hormones than populations living in suburban areas.
The report points out that among the consequences of human activities on nature, the impact of noise pollution is “underestimated,” especially when compared with biodiversity loss and the effects of climate change. The International Union for Conservation of Nature (IUCN) stated last October that about 61% of global bird species populations have declined.
Carter, senior author of the report and Associate Professor at the University of Michigan, says that there are already many available methods to combat noise pollution. For example, building designs can improve visibility to reduce the chances of birds colliding with glass, and similarly, sound can be blocked through design. 'We know what methods to use, and how to use them. All it takes is enough awareness and willingness to do it.'