New Hampshire bats have been in trouble since 2009, when a fungal disease known as white-nose syndrome wiped out most of the state’s population.
Since then, scientists at the University of New Hampshire, New Hampshire Fish and Game and volunteers have been working together to monitor the health of the remaining bats – which are vital to the state’s ecosystem.
“If we lose bats on the landscape, we lose that natural predator of agricultural pests, some of which we as humans are maybe not that fond of,” said UNH conservation expert Haley Andreozzi. “Think mosquitoes, both for annoyance's sake, but also because of potential disease spread.”
She explained that New Hampshire’s two most common bat species, the little brown bat and the big brown bat, like to use abandoned houses, barns and church steeples as a summer home for female bats and their young.
Since those are mostly on private property, she helps lead an effort with New Hampshire Fish and Game where volunteers count the bats at these colonies twice a summer, so scientists can get a sense of where — and how many — bats are left in the state.
“Without that volunteer participation, we can't even begin to understand where those colonies are — much less get out to all of them to be able to count them,” she said
Now, a new partnership is using acoustic technology to eavesdrop on bats at the sites to get a better understanding of the health of these maternity colonies when they emerge at dusk.
“Bats navigate by sound. They navigate by making really loud, really high frequency sounds,” UNH researcher Laura Klopper said. “We can record those sounds every night and we can turn those sound recordings into a way we can estimate the numbers of bats that are using a structure.”
And it seems like bats are coming back — researchers have seen slow population growth in some of the maternity colonies over the years.