Quarantine has made birds more sultry.
The coronavirus shutdown has had a huge, unintended but generally positive impact on nature — including, new research has found, making birds sing softer, sweeter and sexier.
“When noise levels dropped during the shutdown, their songs actually sounded sexier to other birds in the population,” lead author Dr. Elizabeth Derryberry told the BBC of her study, “Singing in a silent spring: Birds respond to a half-century soundscape reversion during the COVID-19 shutdown,” published Thursday in the journal Science.
Researchers analyzed the songs of the San Francisco Bay area’s white-crowned sparrows, which have been recorded since the 1970s, and found that, in lockdown, with less human background noise, their calls shifted to become quieter and more efficient. When the urban soundscape quieted in the area, “birds responded by producing higher performance songs at lower amplitudes, effectively maximizing communication distance and salience,” confirmed the study’s abstract.
Even before the research was published this week, many locals had observed the difference with their naked ears.
“People were right that birds did sound different during the shutdown and they filled the soundscape that we basically abandoned,” said Derryberry, who is also an associate professor of behavioral evolution at the University of Tennessee. “As we moved out of the soundscape, the birds moved in and I think this tells us something about just how big an effect we have on birdsong and on communication, especially in cities.”
While it is uniquely interesting that birds in such a large, well-known American city should react to a historical event in such a way, responding to lower noise levels with quieter songs is a common response known as the Lombard effect. (It’s a similar concept to the cocktail party effect in humans, where people raise their voices higher in louder rooms to ensure they’re heard.)
The study’s findings are uplifting nonetheless, with positive implications for the human and bird residents of San Francisco.
“This study shows that when you reduce noise pollution there’s almost an immediate effect on wildlife behavior and that’s really exciting because so many things that we do to try to help the environment take a long time to improve,” said Derryberry. “It improves your state of being and mental health to be able to hear more birds and I think the shutdown highlighted that.”
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