Birds sang more softly during the human shutdown
The Mercury News brings us one of the more interesting stories of the day. Scientists have discovered that when we humans produced less noise while we were sheltered in place this spring, the birds sang more softly than when they had to compete with human-produced noise.
The sound levels of bird songs fell by more than four decibels during the shutdown; because decibels are measured on a logarithmic scale, songs were about one-third softer. No longer forced to compete with human pandemonium, birds also dropped their pitch by 160 vibrations per second.
“It highlights how much of an effect that humans have on wildlife behavior — and how quickly wildlife can respond when human behavior changes,” said lead researcher Elizabeth Derryberry, an animal communication expert at the University of Tennessee.
“Nature takes over as soon as people get out of the way,” she said.
“We found clear evidence that birds responded to the reduction in noise pollution during the COVID-19 shutdown,” the researchers reported in the Science journal.
And the study found the birds had a greater vocal range: “Birds also exhibited greater vocal performance in response to being released from masking by high energy, low frequency noise. We found that birds sung at lower minimum frequencies, achieving greater bandwidth songs in newly open acoustic space.”