Maine is home to eight species of bats. One of them is the northern long-eared bat and is now on the federal endangered species list. Credit: Gabor Degre / BDN

Wildlife officials in Maine knew the northern long-eared bat was in trouble seven years ago when it put the animal on the state’s endangered species list. This week the federal government officially acknowledged the species’ yearslong population decline on a national level by listing it as endangered.

It’s an ominous change in status for the long-eared bat, which had previously been listed as threatened by the U.S. Fish and Wildlife Service. Placement on the endangered species list is an indication the bat faces extinction, due in large part to the fungal disease white-nose syndrome.

First documented in this country in 2006, white-nose syndrome has infected 12 types of bats and killed millions. The northern long-eared bat is among the hardest hit, with estimated declines of 97 percent or higher in affected populations, according to the U.S. Fish and Wildlife Service.

Here in Maine, where  white-nose syndrome was first observed in 2011, the northern long-eared bat population has been in a steep decline over the last decade.

“They are doing pretty poorly in Maine,” said Cory Stearns, small mammal biologist with the Maine Department of Inland Fisheries and Wildlife. “We only know they are in three of the caves in the state that we monitor.”

Northern long-eared bats in Maine spend their winters hibernating in groups in caves, known as hibernacula.

Before 2011, the caves monitored by Maine IF&W contained between 300 and 500 bats each. About 20 percent of those bats were northern long-eared bats, according to Stearns. The rest were little brown bats, a species also listed as endangered in Maine.

When the wildlife officials surveyed those caves in 2020, they saw a drastic drop in those numbers.

“They were down to 10 bats in each cave,” Stearns said. “None of those bats were northern long-eared bats.”

That does not mean there are no northern long-eared bats in Maine. Ongoing acoustic observations of bat echolocation sounds indicates they are still around. But the data also shows they are in decline.

On the other hand, the news is a bit better for the little brown bats and another bat species in Maine, Stearns said.

“Looking at data from 2015 through 2022, it does suggest little brown bats and big brown bats may be increasing,” he said. “The little brown number tanked with white-nose syndrome hit, but they may be increasing now.”

Named for white, fuzzy spots that appear on infected bats, white-nose syndrome attacks the animal’s wings, muzzles and ears as they hibernate in their hibernacula. It causes them to wake up to groom to clean the fuzz off themselves, Stearns said.

That, in turn, makes them burn calories and energy they need to survive the winter so they end up starving to death.

There is now some indication that little brown bat hibernacula are forming farther back in cooler parts of caves, Stearns said. Under those conditions, the white-nose syndrome fungus can’t form.

So far, there is no indication white-nose syndrome is easing up on northern long-eared bats.

Maine is home to eight species of bats, according to Stearns, five of which spend winters here. All eight are important members of the state’s ecosystem in terms of insect control.

A nursing mother bat will eat its weight in insects every night, Stearns said. That, he said, helps control pests that damage fruit and timber trees in addition to keeping down the flying insects like mosquitoes that prey on humans.

As a federally endangered species, the northern long-eared bat will receive special protections from the federal government. It will also receive special considerations and have increased regulatory protection in forestry, wind energy, infrastructure and other projects in its home range.

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Julia Bayly

Julia Bayly is a reporter at the Bangor Daily News with a regular bi-weekly column. Julia has been a freelance travel writer/photographer since 2000.