SACHA PFEIFFER, HOST:
For decades, songbirds in big cities have been raising their voices to be heard above the noise.
LIZ DERRYBERRY: This is kind of like a cocktail party. When you go to a party, as people show up, it gets louder and louder. And you also get louder - right? - because you're trying to be heard above that din.
MARY LOUISE KELLY, HOST:
Liz Derryberry of the University of Tennessee. She has been studying that phenomenon in white-crowned sparrows in the San Francisco Bay Area.
PFEIFFER: They're cute, round little birds, says Derryberry's colleague Jenny Phillips of Cal Poly San Luis Obispo.
JENNY PHILLIPS: They've got a kind of gray and brown body, and then they have these black and white racing stripes on their head. And they do love to sing, so they do attract attention to themselves in that way.
PFEIFFER: As the pandemic began and traffic and city noise went way down, the scientists wondered, how would big-city birds respond?
KELLY: Well, Phillips had some earlier recordings of the sparrows taken near the Golden Gate Bridge in 2016. If you listen closely, you can just hear the birds tweeting through the traffic.
(SOUNDBITE OF BIRD SINGING)
KELLY: You can hear that.
PFEIFFER: I can. Well, in April of this year Phillips hopped on her bike with some audio gear and recorded the birds again at the same spot.
(SOUNDBITE OF BIRD SINGING)
KELLY: OK. Even though that song sounds much clearer to the ear, after analyzing the recordings, the scientists say the city's songbirds are actually singing at lower volumes today because they're not fighting be heard.
PFEIFFER: And for those feathered virtuosos, singing more quietly means you can add more flourish. Here's Derryberry again.
DERRYBERRY: Because there's so much less noise, they can sort of expand their song and fill that soundscape, which is higher-performance.
PFEIFFER: The work appears today in the journal Science.
KELLY: David Luther of George Mason University also worked on the study. He says a better song could, in theory, go a long way.
DAVID LUTHER: They're better able to defend the territory from some other male, and they're better able to attract a mate or possibly several mates.
PFEIFFER: Derryberry puts it another way.
DERRYBERRY: Birdsongs are sexier in the city.
KELLY: (Laughter) I think we're going to need more research on that to see if maybe the birds agree.
(SOUNDBITE OF CHARLES MINGUS' "SELF-PORTRAIT IN THREE COLORS") Transcript provided by NPR, Copyright NPR.
