Bat counting event tracks population changes
Attendees learn about species, threats to local colonies
- Mirror photo by Rachel Foor Wildlife Biologist Garrett Harris shows the wingspan of a big brown bat that was caught during a bat counting event at NatureWorks Park on Wednesday night.
- Mirror photo by Rachel Foor Wildlife Biologist Garrett Harris shows a family a big brown bat, one of the most common species of bats in Pennsylvania, during an event at NatureWorks Park on Wednesday night.

Mirror photo by Rachel Foor Wildlife Biologist Garrett Harris shows the wingspan of a big brown bat that was caught during a bat counting event at NatureWorks Park on Wednesday night.
HOLLIDAYSBURG — More than a dozen people turned out to help count bats for the Going Batty Program at NatureWorks Park on Wednesday evening.
During the previous bat counting event on July 12, about 105 bats flew out of the two bat boxes affixed to the side of the red barn toward the front of the park, Wildlife Biologist Garrett Harris said. The bats were counted by the attendees as they dropped out of the bat boxes and took flight.
On Wednesday evening, about 108 bats were counted, with each bat box able to hold between 80 to 120 bats.
Following an educational presentation, Harris led attendees to the back of the park, where a large net had been set up. After about a half hour, a big brown bat was caught, weighed and measured. Harris held the bat — a male that weighed roughly the same as eight pennies — allowing attendees a close-up look.
The big brown bat is one of two of the most common bat species in the state, Harris said, with the other being the eastern red bat. One difference between these species, besides their fur color, is that big brown bats stay in the state year-round by hibernating through the winter.

Mirror photo by Rachel Foor Wildlife Biologist Garrett Harris shows a family a big brown bat, one of the most common species of bats in Pennsylvania, during an event at NatureWorks Park on Wednesday night.
“Of all of the bats that we have in Pennsylvania, five of them are either endangered or threatened and of those five, two are currently listed as federally endangered and one is proposed to be listed here in a few months, and then a year from now, another one is supposed to be recommended for some type of federal protection,” Harris said.
Accurately counting bats is essential for tracking population growth and decline. In addition to habitat destruction, white nose syndrome, which came to the state in about 2008, has seen population die-offs between 90-99%, Harris said.
White nose syndrome is “essentially a ripple effect of a fungus that grows” on bats’ noses, ears and wings, causing them to itch and burn, Harris said. This is a problem for hibernating bats, as it causes them to prematurely wake up.
“When they wake up prematurely, they’re burning these fat reserves off and, because they’re unable to replenish them, they are starving and/or dying of dehydration,” Harris said.
Prior to white nose syndrome arriving in the area, between 30,000 to 40,000 bats lived in the Canoe Creek mine and church, Harris said. After a couple years, the local population was down to about 30 bats.
“Recently, the last count I had with the Game Commission, it was back up to about 789,” Harris said. “I mean, it sounds like a lot from 30-some to 700-some, but in the grand scheme of things, when you think of 30,000 to 40,000, down to 700, that’s not good.”
Since bats are “extremely important to our ecosystem,” the sharp decline in their population is a problem as their diet consists of insects, Harris said.
“If they’re unable to keep the insect population in control, that not only means more insects that are going to bother us, but it’s also going to impact crops,” Harris said. “When it impacts crops, farmers and other agricultural professionals will have to spend more for pest control for their crops so they’re viable to eat and that translates to more expensive food.”
Bats are able to consume anywhere from 25% to 100% of their body weight and up to 1,200 insects a night, Harris said.
“So you multiply that by 100 or 1,000 bats and that starts getting pretty significant,” Harris said.
Mirror Staff Writer Rachel Foor is at 814-946-7458.