Scientific research. Street noise harms birds

– Sound has a much stronger and more direct impact on the development of birds than we previously thought – said Dr. Mylene Mariette, an expert in bird communication from Australian Deakin University. The research was published in the journal “Science” and described by the British Guardian.

Mariette's team exhibited eggs of Australian zebra finches (Latin: Taeniopygia guttata castanotis) for five days of silence, the soothing sounds of these birds, or recordings of city traffic sounds such as the roar of engines and passing cars. The researchers did the same with newborn chicks for about four hours for up to 13 nights, without exposing the bird parents to these sounds.

If bird eggs were exposed to traffic noise, chicks were 20 percent less likely to hatch, scientists found. Those that hatched were more than 10 percent smaller and almost 15 percent lighter than the remaining chicks. When the team examined their red blood cells and their telomeres, a piece of DNA that shortens with exposure to stress and age, they were more damaged and shorter than their counterparts.

The researchers also found that the negative effects persisted even after the chicks stopped being exposed to noise pollution and moved into their reproductive years four years later. Birds that were exposed to noise early in life gave birth to half as many offspring as those that did not have to listen to disturbing sounds.

– We expected some effects, but not that strong, especially since the noise exposure was relatively mild and lasted only four hours a day. It was really striking, Mariette explained. She said research shows that the response to noisy stimuli is innate and spontaneous, and what underlies it remains unclear, but “it is something that is probably common to all species.”

Australian zebra finches are birds living in Australia, but they are also willingly bred in cages all over the world.