San Francisco. When the roads emptied of traffic in March and April because of the COVID-19 pandemic, Bay Area residents reported hearing more birds—and they were halfway right.
Jennifer Phillips, a researcher at Cal Poly, and Elizabeth Derryberry, a professor at the University of Tennessee in Knoxville, collaborated to evaluate whether and how songbirds responded to the quieter environment with much less traffic.

They compared the soundscapes and songs of the white-crowned sparrow recorded across the San Francisco area prior to and during the statewide shutdown.
“When I saw photos of an empty Golden Gate Bridge, it struck me just how little traffic there was,” said Derryberry, lead author of the study. “I realized we were in a unique position to look at how changes in human behavior might affect wildlife and what the noise reduction might mean for the songbird we study.”
The researchers found that the birds responded by producing softer songs that could travel over a larger distance, unimpeded by noise. The urban songs also became “sexier” in terms of vocal performance—meaning birds sang a wider range of notes in their song, in a wider bandwidth, during the shutdown.…




