Going Batty with CT DEEP Wildlife Biologist Devaughn Fraser

Going Batty with CT DEEP Wildlife Biologist Devaughn Fraser

On the evening of July 24, I was joined by 28 intrepid TLGV members, their children and friends at the Wyndham Land Trust’s Lyon Preserve in Pomfret. We were there for a program led by CT DEEP Wildlife Biologist Devaughn Fraser. She is an expert on small mammals with a specialty studying bats, and we were there to observe and help her count the bats that had established a roost in the barn at the preserve. It was a clear warm night and July rains had caused an increase in the mosquito population. Bats are expert mosquito eaters, and that evening we knew there were plenty available for their dinner.

I first learned of this bat roost from Andy Rzeznikiewicz, a Connecticut Audubon staff member and Wyndham Land Trust land steward. He was happy to allow us to use the preserve and a few more members of Wyndham Land Trust also joined our group that evening. Andy purposely leaves open two windows just below the front and back peaks of the barn, so the bats have easy access in and out. He has also installed a bat house just below the window on the south side of the building.

Devaughn brought instructions with her for hand-counting bats as they emerge from the roost. She also provided a brief program about bats, including information about the species of bats known to live in this region and the devastating effect of white-nose syndrome, a disease first discovered in the United States in 2006. This disease has significantly impacted several bat species around the country, especially those that roost and hibernate in caves. One of the most common bats in our region, the little brown bat, has been decimated with a population decline of more than 90 percent.

Soon after sunset it was time to get into position to count bats as they left the barn to feed on insects. Devaughn gave a few of the children hand counters to tally the bats as they flew out the windows or dropped from the bat house. The hand counters are small handheld devices; with your thumb you press a clicker that activates the counter inside the device. Devaughn had us use two hand counters for each window. One to count bats as they exit the windows and a second to count any that go back in the windows.

I have never seen so many bats at once and the darkening sky seemed filled with them. To get the final count we subtracted the number of returning bats from the exiting bats to avoid double counting bats that exit the barn twice. Within an hour we counted 186 bats, though we’re pretty sure we missed some earlier in the evening before we were in place with the counters. All in all, that roost may very well be the summer home to more than 200 bats.

Devaughn also set up two echolocation recording microphones plugged into laptops. On the laptop screen we could see the shape and kilohertz (kHz) of each call. From the shape of the call and the frequency of the kHz, biologists can determine the bat species.

That night the bats at Lyon Preserve were the big brown bat species, the most common bat in our region. Even though common, big brown bats are still listed on the CT DEEP Wildlife Action Plan of 2015 as a species of Greatest Conservation Need. They typically roost in buildings, and we were delighted to help get a good count that evening to be included in the statewide number for this species.

Following the program, I contacted Devaughn for more information about roosts and bat colonies in the state. She said “over the course of the last 10 years CT DEEP has documented 135 roosts in the state (the majority of which have been the big brown bat). Most are monitored by volunteers or landowners. Unfortunately, the very few little brown bat colonies that we know of have all but disappeared with only two still active.” She plans on focusing her efforts on more monitoring of little brown bat colonies in the months and years ahead.

One of the people attending our program in July has bats roosting in his barn. He attended specifically to learn more, and his barn roost will now be included in the survey.

Regular readers may remember my previous columns describing my volunteer work for CT DEEP monitoring and counting bats over a 20 mile transect route between Putnam and Windham. I am one of nine volunteers doing this. Each of us does a separate location twice a month between May and September. We drive a prescribed backroad route (no more than 20 mph) with a powerful microphone attached to our vehicles that records the echolocation calls of feeding bats. CT DEEP uses these recordings to determine the number, species and location of bats to help ascertain their population in the state. It is rewarding work.

Devaughn is always looking for more volunteers, especially to help run the mobile transect surveys. I plan on continuing my Putnam to Windham transect and will also help with surveying the roost at the Lyon Preserve.

If you’re interested in learning more about bats in our region, and the impact of white-nose syndrome, you’ll want to check out the CT DEEP website. A link is provided below.


Bats are fascinating mammals and ecologically important for pest control, and some are also pollinators. The more we learn about this important animal the better informed we are about the challenges facing our region’s bat population.

We live in a beautiful place called The Last Green Valley National Heritage Corridor. Our region is rich in natural and cultural resources, and I hope you’ll join me and so many others to care for it, enjoy it and pass it on.

Bill Reid is the Chief Ranger of The Last Green Valley National Heritage Corridor. He can be reached at 860-774-3300 or bill@tlgv.org



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