While social distancing measures have pushed many people into sexless, joyless bubbles, San Francisco birds are getting flirtier and more coy. I’m glad someone’s getting some.
Coronavirus precautions and shutdowns have have made cities a lot quieter. In a study published in Science this week, researchers found that, with fewer cars roaring, people chattering, and construction projects whirring, white-crowned sparrows are changing their songs.
Like many birds, white-crowned sparrows use their musical calls to communicate. Males are particularly reliant on their song, which they use to find mates and delineate their territories.
The researchers have been observing the sparrows’ singing in the Bay Area for years. In their previous work, they have shown that increasing urban noise levels — mainly from the low-frequency din of traffic and air conditioners — has caused the birds to start singing louder and shriller songs.
This higher-frequency sound carries across greater distances but is generally less effective for males looking to woo females, who preferred the the subtle, sweeter songs of quieter times.
Now that noise levels are dropping and birds don’t have to sing so high and strain their voices, those songs of yore are back.
“Our analysis shows that the shutdown effectively erased 50 years of noise pollution,” Jenny Phillips, a behavioural ecologist at California Polytechnic State University who worked on the study, wrote in an email.
The scientists compared birdsong data from April through June of 2015 and 2016 with recordings taken at the same sites from April through May 2020. They found that the trills were far prettier and almost a third quieter. The songs also featured a wider range of pitches and were packed with more information. Even with these changes, the sparrows’ calls could still be heard from twice as far away compared with before the shutdown.
“I would describe the songs during the lockdown as being quieter, higher quality, and travelling farther,” David Luther, assistant professor of biology at George Mason University and a co-author of the study, wrote in an email.
Philips put it more simply: She said the songs were “sexier.”
It makes sense. Think about trying to spit game with someone in a loud, crowded bar. You can’t say very intricate things when you’re yelling over the roar of people doing shots and shouting along to Migos.
The changes in tune were far more notable for birds in urban areas, which likely made city birds more capable of competing for breeding territories.
These sultrier calls and quieter conditions are good news for white-crowned sparrow populations. Previous research shows that, due to prevailing noise pollution, birds were having trouble mating. Noise can also screw up birds’ ability to hear other birds’ warnings of predators and the whines of their own chicks. The resulting stress, scientists have found, can also disrupt their metabolisms. All of this has likely played a role in the massive decline of bird populations.
The research highlights the role that regulations on noise pollution could play in helping build these populations back up. And in the meantime, many San Franciscans may not be getting laid, but at least they can hear these beautiful songs.