When Rachel Carson wrote an environmental classic silent spring<\/em> In 1962, she warned that unchecked impacts on humans could create a quiet future.<\/p>\n Forty years later, biologists have discovered the striking effects of noise pollution on songbirds. They found that low-pitched traffic noise forced birds to sing at higher pitches in European cities. Songbirds in a noisy park beneath the Eiffel Tower sang at a pitch 400 Hz higher than those in a quiet forest outside Paris.<\/p>\n My new research was published in a scientific journal ornithological applications<\/em> My colleague Hans Slavbekoorn from Leiden University and his colleagues have shown that Paris is a success story in the fight to reduce noise pollution.<\/p>\n But even as Paris has become quieter, the birds have not regained their natural song frequencies. Our research shows that great tits in Paris continue to sing at higher pitches than birds in natural areas outside the city.<\/p>\n Further noise reduction efforts are essential in urban areas around the world to enable wild birds to communicate using natural sound frequencies.<\/p>\n Human activity fills the world with noise. The sounds of cars, airplanes, boats, and industrial activities create continuous noise that affects wildlife, birds, and insects. We often overlook noise pollution as a conservation issue, but in an era of increasing urbanization, noise pollution can have devastating effects on wildlife.<\/p>\n Road noise interferes with birds and frogs’ ability to attract mates. Boat noise leads to decreased vocal communication in whales. Traffic noise also affects predator-prey interactions between moths and bats.<\/p>\n Ever since it was discovered that low-pitched traffic noise caused birds to sing at higher pitches in European cities, this pattern has been demonstrated in diverse bird populations around the world.<\/p>\n A savannah sparrow sings a high-pitched song near a noisy oil pump on the Canadian prairies. European robins sing high-pitched songs in the presence of windmill noise. And Australian silvereyes sing higher-pitched songs and calls in urban areas compared to rural areas.<\/p>\n These changes reduce the birds’ ability to protect their breeding grounds and attract mates.<\/p>\n \n Read more: Human activity is making Arctic waters louder Paris is one of Europe’s largest and most densely populated cities, but Parisians have developed a new strategy to combat noise pollution. <\/p>\n The city has converted many roadways into bicycle lanes and installed noise-absorbing coatings on major roadways. <\/p>\n Automatic noise cameras issue fines for excessively noisy vehicles. A regional observatory called Bruitparif currently monitors noise throughout the city and oversees noise reduction efforts.<\/p>\n These noise reduction efforts in Paris will make the city quieter for both people and wildlife. The city’s campaign in the fight against noise has raised questions about whether the volume of noise pollution can be lowered to minimize its impact on bird songs.<\/p>\n In 2023, I traveled to Paris to record great tit songs. The great tit is a well-known backyard bird in Europe and is closely related to the great tit. <\/p>\n I used a microphone and a digital recorder to record birds on the city’s streets, squares, and parks. I followed in the footsteps of my first biologist collaborator, Hans Slabbekorn, who recorded great tits in Paris in 2003. <\/p>\n By comparing ambient noise with bird songs, they found that great tits sing high-pitched songs in noisy environments. Great tits sing at a high pitch to avoid having their songs masked by the low-frequency noise of traffic.<\/p>\n We also analyzed noise data collected by Bruitparif across Paris. It turns out that Paris is winning the battle against noise pollution, and the city has become quieter in recent years. In fact, Paris is about 3 decibels quieter today than it was 10 years ago. The decibel scale is logarithmic, so a drop of 3 decibels represents a significant drop in sound intensity.<\/p>\n Despite these advances, Parisian great tits continue to sing at a higher pitch than birds in natural areas outside the city.<\/p>\n But there are also reasons for optimism. Studies have shown that when cities become quiet, birds elsewhere return to their natural pitch.<\/p>\n The quiet streets during the coronavirus lockdown provided a rare opportunity to study birds in a quiet world. Biologists in San Francisco found that the city’s soundscape became about 7 decibels quieter during lockdown. This level has rarely been observed since the 1950s. <\/p>\n Silent radio waves allowed the birds to change their sounds. The San Francisco sparrows responded by singing a lower pitched, quieter song.<\/p>\nThe devastating effects of noise<\/h2>\n
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\n <\/em>\n<\/p>\nfight for quieter cities<\/h2>\n
\n (Dan Menil)<\/span><\/span>
\n <\/figcaption><\/figure>\nlower the racket<\/h2>\n
![\"The](\"https:\/\/hyokal.com\/wp-content\/uploads\/2026\/04\/Paris-succeeds-in-reducing-noise-pollution-but-urban-birds-still.0&q=45&auto=format&w=754&fit=clip.jpeg\")
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\n (Dan Menil)<\/span><\/span>
\n <\/figcaption><\/figure>\nbirds can send back sounds<\/h2>\n