NASHVILLE, Tenn., (WKRN) — Early on in the COVID-19 pandemic – back in March and April – many Middle Tennesseans reported unexpected encounters with wildlife. Suddenly, sightings of deer, coyotes, and other animals seemed to be on the increase. Another thing that was more noticeable than before, birds singing. Were the birds suddenly singing louder? Or were we just able to hear them without the noise of traffic in the background?
Elizabeth Derryberry, a behavioral ecologist at the University of Tennessee, realized the pandemic offered an unprecedented opportunity to study birdsong without the usual sounds of city life. The landscape had changed drastically due to COVID-19, but what about the soundscape?
That was the question Derryberry and her collaborator sought out to answer. “When people change their behavior and there’s a lot less traffic, then do we affect the soundscape?” she questioned. “Is it quieter? And do birds change their song because of that?”
Derryberry’s research focused on the white-crowned sparrow, a common songbird. During the lockdown in San Francisco, the ambient noise was reduced by up to 50 percent. The white-crowned sparrow responded, with sultrier tunes.
“In response, the birds themselves also got quieter, and because they got quieter, the quality of their song also increased. So, we like to say, colloquially, they were sexier during the shutdown,” Derryberry said.
Songbirds do two things with their songs. They attract potential mates and they also warn other males of the location of their territory. The pandemic shutdowns happened at just the right time.
“The lockdown was when they were breeding. It was when that song actually matters. If it had happened in January or August, it wouldn’t have told us as much scientifically. The timing of it was really interesting.”
Derryberry believes that the birdsong in Nashville was going through similar changes to that in San Francisco. The lower noise levels mean quieter but higher quality birdsong. As noise levels go back up, the volume of birdsong is expected to as well.
“They’re very flexible, and so I think that the same thing’s going to happen when it gets louder again with the increase in traffic noise and everything. They will shift their song back, and we’re hoping to study that.”