At the Hubbard Brook Experimental Forest, Jessica S. Jones is studying bats by recording audio imperceptible to the human ear.
The doctoral student at Dartmouth works with two detectors that can record the high-frequency noises emitted by bats as they use echolocation to navigate and hunt for insects at night in the forest that stretches across the White Mountains’ towns of Woodstock and Ellsworth.
Then she uses a new technology that listens for ultrasonic bat sonar signals to identify them, as part of efforts to track and monitor at-risk species.
Jones said the software, called SonoBat, uses machine learning and can automatically detect what kind of bat is present in the recordings. The technology is taking off, given just how much data is collected from acoustic recordings.
“It took 40 hours of work and brought it down to, like, four hours of work,” she said. “Then we can go back and look at what the program identified it as and verify ourselves. We’re still in control.”
Similar technology can be used for birds and bats, she said. Jones started using the technology in 2019, and an update this year also allows researchers to hear “feeding buzzes” from the bat recordings.
In New Hampshire, there are eight species of bats, and all of them are designated as species of conservation concern. Bats are generally nocturnal and can eat up to half their weight in insects per day. They are also pollinators, and about 500 flowers worldwide depend on them, according to Bat Conservation International.
Starting in 2008, a fungal infection called White-nose Syndrome reached the state and began decimating some of its bat populations, according to New Hampshire Fish and Game. In 2011, The agency reported that bat mortality was “devastating,” and surveys only found 16 bats in areas that were previously home to large populations.
Jones said while bats have developed some resistance to the fungus, the rebound of the population will be slow because the decline was so dramatic. Bats can live up to 20 years, and they only have one to two pups per year.
She said that although bats have long been misunderstood creatures, she’s optimistic their reputation is improving.
“I think people are starting to get more appreciative of bats,” she said.
This article was updated to correct the name of the US Fish and Wildlife Services. This article first appeared in Globe NH | Morning Report, our free newsletter focused on the news you need to know about New Hampshire, including great coverage from the Boston Globe and links to interesting articles from other places. If you’d like to receive it via e-mail Monday through Friday, you can sign up here.
Amanda Gokee can be reached at amanda.gokee@globe.com. Follow her @amanda_gokee.