Birds In Shutdown Cities Not Louder, Just Bolder

In the pandemic City you can hear more bird song and it appears to be louder. While people made the assumption that was because there was less ambient noise, Elizabeth Derryberry, an associate professor of behavioral evolution and phylogenetics at the University of Tennessee, Knoxville has been studying white-crowned sparrows in the San Francisco area since 2012 and had recorded bird song from that pre pandemic time

By comparing bird song recordings from the Spring of 2015, Dr. Derryberry and her team analyzed “vocal performance”. And they found that the sparrows’ songs had not got louder, but had grown to have more tonality. As Sarah Holder with CityLab stated “they got “sexier.” The birds were able to say more, and say it better, because they didn’t have to shout so much.”

Before the pandemic sparrows in the San Francisco area lived in habitats three times noisier than their rural cousins. Lockdowns contributed to an ambient noise background, conformed by traffic data showing that vehicular traffic and crossings of the Golden Gate Bridge were at low levels not seen in over sixty years.

Even with male sparrows singing 30 percent less loudly, the bird song travelled twice the normal distance. The sparrows seemed to start to improvise with this, with new “trill” patterns not heard in the last fifty years.

Male sparrows started singing about 30% more softly, but since the roar of the urban world had dropped by more than 50%, their signal carried twice as far. Features that hadn’t been heard since the 1970s reappeared, along with new trill patterns. “

With a 13 month lifespan, Dr. Derryberry posits that the male birds who can adapt to a changing soundscape may be part of an “evolutionary adaptation ” and that songbirds in other cities may be also changing their song.

“Whether it’s plasticity or selection, whatever it is, I think these birds are on a new trajectory,” she said. “Their songs have entered an acoustic space they haven’t been in over 30 years. I really doubt they’re just going to go right back to where they were before.”

Here’s a YouTube video of Dr. Derryberry’s sparrow work. The changing sparrow sound is not attached to this video, but can be listened to on the soundcloud segments attached to this link.