Study finds traffic noise stunts growth of baby birds

Research has found that traffic noise pollution stunts the growth of baby birds, even inside the eggs.

Research has found that exposure of unhatched birds and young birds to urban traffic noise can have long-term negative effects on their health, growth and reproduction.

The impact of sound on bird development is much stronger and more direct than we previously knew, said Dr. Mylene Mariette, an expert in bird communication at Deakin University in Australia and co-author of the study published in the journal Science . It would be wise to increase efforts to reduce noise pollution.

A growing body of research shows that noise pollution stresses birds and makes communication more difficult. But it’s unclear whether birds become distressed at a young age because they are exposed to noise or because noise disrupts their environment and parental care.

Mariette’s research team typically exposes zebra finch eggs to a quiet environment for five days, plays the soothing sounds of a zebra finch song, or records urban traffic noise, such as revving engines and passing cars. They conducted the same experiment with newborn chicks, about four hours a night for up to 13 nights, without exposing the parents to sound.

They noticed that bird eggs were nearly 20 percent less likely to hatch if exposed to traffic noise. The hatched chicks are more than 10% smaller and nearly 15% lighter than other chicks. When the team analyzed their red blood cells and telomeres (a stretch of DNA that shortens with stress and age), their red blood cells and telomeres—a stretch of DNA that shortens with stress and age—were more eroded and shorter than those of their peers.

The effects persisted even after the chicks were no longer exposed to noise pollution and continued into breeding age four years later. Birds that were disturbed by noise in their early stages of life produced less than half the number of offspring as their counterparts.

Mariette said we expected some impact but didn’t expect it to be so large, especially since the exposure to noise pollution was relatively mild and only lasted four hours a day. This is indeed very striking.

Robert Dooling, an animal hearing expert at the University of Maryland, said that based on a large number of studies, we generally believe that very young birds, especially in eggs, have very poor or no sensitivity to sound. But the research raises concerns about the widespread, negative, and lasting impacts of noise on development.

Hans Slabbekoorn, a professor of acoustic ecology and behavior at Leiden University in the Netherlands who was not involved in the study, said he was particularly surprised. When his team conducted experiments in which chicks and their parents were exposed to moderate levels of noise pollution, they found no effects on chick growth.

Slabekun speculates that changes in parental behavior, such as them taking more care of their nests, may have avoided or compensated for the negative effects of noise on nestlings.

I really didn’t expect [such a] The impact must be huge, Slabbekoorn said. He added that it’s the cumulative nature of these negative impacts that may ultimately create the biggest problems. Especially when noisy environments are indeed frequent or persistent, such as when birds live in noisy neighborhoods, near airports, or on busy highways.

His research also found that birds at airports may become partially deafened when exposed to such high noise levels.

More data are needed to determine how many birds and which species these levels apply to, and it is unclear whether it is the loudness, pattern, pitch, or other elements of traffic noise that disturb young birds, or the mechanisms that disturb young birds. Effect.