Bay Area birds change their tune amid COVID-19 shutdown - The Mercury News

A first-ever acoustic comparison of avian songs before and during the springtime shutdown reveals that birds respond quickly when humans hush.

They sang more softly — and these songs were faster, with a wider, lower and more romantic range of pitch, according to the study, published in Thursday’s issue of the journal Science.

The sound levels of bird songs fell by more than than four decibels during the shutdown; because decibels are measured on a logarithmic scale, songs were about one-third softer.

White-crowned sparrow (Zonotrichia leucophrys) male singing to defend his territory and attract mates in San Francisco, CA, USA.

Jennifer Phillips is a postdoctoral researcher at California Polytechnic State University, San Luis Obispo, where she studies the effects of noise pollution on bird communities.   (Courtesy of JN Phillips).

White-crowned sparrow (Zonotrichia leucophrys) male singing to defend his territory and attract mates in San Francisco, CA, USA.

White-crowned sparrow (Zonotrichia leucophrys) male singing to defend his territory and attract mates in San Francisco, CA, USA.

Then she saw a photo of the near-empty Golden Gate Bridge, with vehicle traffic at levels not seen since 1954 — reversing more than a half-century rise in noise pollution.

And wondered: “Are the birds singing differently?” Unable to travel, she enlisted the help of former graduate student Jennifer Phillips, who was doing postdoctoral work at Cal Poly San Luis Obispo.

Scientists have collected vast archives of Bay Area sparrow songs, dating back decades and safely stored at the California Academy of Sciences.

Singing is critical to a bird’s survival, helping it find a mate and defend territory.

Even though birds sang more softly, their songs traveled twice the distance

The scientists will continue their research to learn if bird behavior changes again, in response to our ever-more crowded soundscape — and if next year’s chicks will learn their parents’ songs, or adapt to their new and more noisy world

“If we reduce our noise pollution — driving less, using electric cars, changing how we build our roadways — hopefully they will be more successful in urban environments.”