Beyond the Bats

ost people come to Bracken Cave Preserve for the bats, since it’s home to the largest known bat colony in the world. On summer evenings north of San Antonio, visitors gather in the viewing area, waiting for the first movement at the cave mouth. Then the spiral begins: more than 15 million Mexican free-tailed bats (Tadarida brasiliensis) pour into the sky in an inky black ribbon that twists upward before spreading across the Hill Country.

What most visitors don’t see, or even think about, is what happens before and after the bat flights.

Earlier that same day, volunteers may have been clearing trails in the Texas heat, leading a butterfly survey, searching for hard-to-find Endangered plants, or teaching children why bats matter to Texas ecosystems.

“People think of Bracken as just a cave,” says Fran Hutchins, Director of Bracken Cave Preserve. “But it’s so much more.”

That “more” stretches across roughly 1,500 acres of protected Hill Country habitat supporting not only the world-famous bat colony, but also birds, butterflies, reptiles, native plants, and at least eight other species of bats. Much of the work that keeps the preserve functioning is powered by volunteers.

The preserve’s volunteer program began growing in earnest around 2013. Now, roughly 300 volunteers contribute thousands of hours annually, from trail maintenance and visitor education to wildlife surveys and habitat restoration. Many volunteers come to the preserve through the Texas Master Naturalist program, a statewide conservation education initiative that trains volunteers in ecology, wildlife, and land stewardship.

Others simply fall in love with the preserve and keep showing up.

“We make it fun,” Hutchins says. “If you don’t want human contact, you can work on trails. If you love talking to people, you can teach kindergarteners or other groups about bats. There’s a lot to do.”

That variety is part of what keeps volunteers engaged year after year.

“Most people don’t know it’s not just one cave, but caves, plural,” says Hutchins, who came to the preserve through an interest in caving. “We have one big cave, which is Bracken Cave, but to date, we have discovered an additional 15 smaller caves. One of our volunteers, Dana Murray, discovered a cave while doing a karst survey.”

During bat flight season, which runs from May through September, volunteers help coordinate parking, greet guests, check reservations, and guide visitors through the preserve before leading interpretive talks about the bats and the surrounding ecosystem. But once bat season slows down, the work continues.

Volunteers conduct bird and butterfly surveys, monitor cave systems, assist with white-nose syndrome (WNS) research, maintain trails, document species through the iNaturalist app, and participate in “BioBlitzes,” which are community science events where participants identify as many species as possible over a set period of time.

“We’re not just bats,” says volunteer Karla Kahn. “We have bees, birds, plants, butterflies, and more.”

Kahn, who has a professional background in research science, first discovered Bracken through the Texas Master Naturalist program. She said volunteering at the preserve reconnected her with science and the outdoors after years away from research work.

Now, she assists with bat surveys, cave research, and a Tulane University project studying swanflower (Aristolochia erecta), which is the only plant where the pipevine swallowtail butterfly (Battus philenor) lays its eggs.

“There are 1,500 acres out there, and Fran has charged us with finding this tiny little plant hidden in the grass and marking each one with a flag,” Kahn laughs.

Volunteer Coco Brennan also came to the preserve through the Texas Master Naturalist program more than 20 years ago. She now splits her time between community outreach and community science projects.

Some days, she’s leading surveys of golden- cheeked warblers (Setophaga chrysoparia), an Endangered species of bird. Other days, she’s visiting schools or community events, teaching children about bats.

“I’ll go anywhere and talk to anybody about bats,” Brennan says. “I’ve talked to garden clubs, schools, community groups, whoever wants to listen.”

The golden-cheeked warbler and Bracken’s famous bats rely on different parts of the preserve, but volunteers say the connection between them is the habitat itself. The bats depend on the cave system, while the warblers nest only in Central Texas woodlands containing mature Ashe juniper and oak trees. Protecting the preserve means protecting all of it together.

“The bats are here because of the cave,” Brennan says. “The birds are here because of the habitat. The insects are here because of the plants. They all depend on each other.”

Each spring, trained volunteers conduct repeated golden-cheeked warbler surveys across the preserve, returning to the same locations multiple times throughout nesting season to document sightings and songs. The surveys help Bracken maintain its designation as an Important Bird Area through BirdLife International.

For many volunteers, those surveys reinforce that Bracken functions as a full ecosystem rather than simply a tourist destination that’s famous for bat flights.

“It’s not just the bats,” Brennan says. “It’s the landscape we protect, the plants, the insects, the birds. It’s all connected.”

For volunteer and artist MV Barnes, Bracken became both a conservation project and a creative outlet.

A graphic artist by trade, Barnes has designed everything from trail signs and maps to gift cards for the preserve. More recently, she completed a mural wrapping around Bracken’s bird blind featuring native wildlife and plants found throughout the property.

The mural depicts skunks, birds, cacti, grasses, and Hill Country flora, reflecting the broader ecosystem volunteers work to protect.

“There are animals and plants people may never even notice when they come out for the bat flights,” Barnes says. “I wanted the mural to reflect all of it.”

The mural also includes two human figures: longtime volunteers Don and Edith Bergquist, a retired couple whose property borders the preserve, and who have become mentors and welcoming fixtures within Bracken’s volunteer community. Barnes and other volunteers describe the Bergquists as part of the culture that keeps people returning year after year.

The Bergquists became connected to the Bracken Preserve shortly after building a house on a hill near the cave, which their real estate agent didn’t tell them about. They were sitting on their porch enjoying a glass of wine one evening and were surprised to observe a vast swarm of bats fly out. They visited the preserve the next day to learn more about what they’d observed, and the rest is history.

“I probably wouldn’t be talking to Bats Magazine if it weren’t for them,” Barnes says of the Bergquists. At sunset, the couple can often be seen riding around the preserve on their ATV.

Describing herself as “an introvert by nature,” Barnes says leading a public-facing bat tour once would have felt intimidating. But when Don Bergquist suggested she try it, she found herself saying yes without hesitation.

Like many volunteers, Barnes started with physically demanding land management projects before eventually becoming a lead docent during bat flight season. She now guides tours, leads public hikes, and helps with educational programs throughout the year.

“The bat flights are magical,” she says. “But the best part is really the community out there.”

That sense of community comes up repeatedly among volunteers. So does a kind of shared curiosity. Many describe Bracken not only as a place to teach others about nature, but as a place where they are still constantly learning themselves. Barnes described Bracken as “my happy place,” adding, “It makes the seven-year-old in me very happy.”

Volunteer Dana Murray similarly describes the preserve as “a wonderland.”

“There’s just so much trust out there,” Murray says. “They let volunteers help represent the preserve and the bats and the science. That’s special.”

Over the years, Murray has participated in cave surveys, bird projects, educational outreach, and bat flights. Like others, she said many visitors don’t fully understand what a preserve actually does.

“We’re preserving what’s already there,” she says. “You can’t preserve something unless you understand it first.”

Volunteers also shared vivid memories of moments that deepened their connection to Bracken and its mission.

A standout volunteer moment for Barnes came when she had the opportunity to ride a bicycle in a San Antonio parade, dressed as a bat. “We partnered with BCycle, a local electric bike share company, and rode in the Fiesta Parade,” Barnes explains. “It was so much fun.” Fiesta San Antonio is a citywide two-week celebration each April and the preserve’s lighthearted participation reinforces how much the volunteers, and the bats, are tied to this community.

Kahn had a different kind of “wow” experience. While visiting Bamberger Ranch Preserve in nearby Johnson City to do a WNS survey, Kahn found herself in the middle of a “batnado.”

“The ranch owner had built a man-made bat cave on his property that was inspired by Bracken Cave, which was pretty incredible to see,” Kahn says. “I stepped into this cave and all of a sudden, I found myself standing in the middle of these swirling bats and feeling the bats all around me. I was inside the bat tornado, and I was just in awe.”

Kahn adds that this experience isn’t something that a visitor to the preserve would get to do, although they do get close enough to see this in action. Sometimes a wind shift draws the tornado-like formation closer to the guests, and they have a more intimate experience with the bats than what is usual.

While millions of bats remain Bracken’s most visible residents, Hutchins said the preserve’s broader mission continues expanding, particularly through research partnerships with universities, wildlife groups, and conservation organizations.

“People come for the bats,” he says. “But then they realize there’s this whole other world out here.”

By the time visitors leave after a bat flight, most never see the volunteers locking gates, checking trails, or preparing for the next day’s survey work.

But the preserve doesn’t go quiet once the bats disappear into the night sky. If anything, that’s when much of the behind-the-scenes work begins.