Places We Protect

Frank Klein Cibolo Bluffs Nature Preserve


Cibolo Creek gently flows between the rolling, green vistas of the Texas Hill Country, dotted by cactus and shrubs.
Cibolo Bluffs Preserve View of Cibolo Creek. © Jerod Foster

A partnership to protect the golden-cheeked warbler is a conservation win for all.



Situated about 20 miles northeast of San Antonio, The Nature Conservancy's (TNC) Frank Klein Cibolo Bluffs Nature Preserve is a scenic landscape that encompasses nearly three miles of Cibolo Creek. Now spanning just over 2,000 acres, the preserve was originally established to protect a federally endangered Central Texas songbird: the golden-cheeked warbler.

The preserve's sprawling landscape is dotted with craggy limestone outcroppings and features mature Ashe juniper and other trees that the golden-cheeked warbler relies upon. Wildflowers such as blue curls and tree species like Plateau live oak, Buckley’s oak and cedar elm can be found here too. As daylight fades into evening, Mexican free-tailed and other bat species take to the sky, feasting on insects before returning to their roost.




Millions of Mexican free-tailed bats


2,013 acres

Explore our work in Texas

Going to Bat for Mexican Free-tailed Bats

Going to Bat for Mexican Free-tailed Bats (6:04) Together with Bat Conservation International and the City of San Antonio, TNC purchased 1,521 acres adjacent to Bracken Bat Cave, protecting the largest bat colony in the world, preserving habitat for endangered species and safeguarding water for San Antonians.
The Cibolo Bluffs Preserve sign sits on a wire fence.
HILL COUNTRY HABITAT The Frank Klein Cibolo Bluffs Nature Preserve is an island of refuge for wildlife and nature in one of the fastest developing regions. © Jerod Foster

Why This Place Matters

TNC created Cibolo Bluffs, in partnership with Bexar County and the U.S. Army, as rapid development began to encroach on the land surrounding Camp Bullis—a 28,000-acre military installation that was fast becoming a "lone island of refuge" for the golden-cheeked warbler. These songbirds only nest in the mature oak and Ashe juniper forests of Central Texas, and the region’s continued growth has had a drastic impact on warbler populations. TNC entered into a cooperative agreement with the Army to protect warbler habitat off-site in exchange for mitigation credits, which allow the Army to clear vegetation and develop property surrounding the camp.

In addition to this, Cibolo Bluffs safeguards land over the Edwards Aquifer, helping maintain the quality and quantity of water that recharges this freshwater source relied on by many. As rain percolates through the preserve's shallow soil and underlying limestone, it creates sinkholes, caves and other karst features before finally flowing into the aquifer—which provides drinking water for more than two million Central Texans, including the city of San Antonio.

Photos from Cibolo Bluffs Nature Preserve

Discover the diverse plant life and wildlife at this scenic Central Texas nature preserve.

A golden-cheeked warbler sits on a branch singing with bright yellow cheeks, a white chest and black mottled wings.
A closeup of a hand holding a piece of white limestone with many eroded holes and at least three possible carved artifacts, similar to arrowheads.
Five clustered goldeneye phlox flowers bloom in varying shades of pink petals with yellow centers outlined in white.
Millions of bats fly and swirl as they emerge from Bracken Cave at dusk while visitors stand in the background watching them take flight.
An orange Julia butterfly sits with its wings spread on a yellow flower.
A patch of bluebonnets bloom against bright green leaves in a field at Cibolo Bluffs.
A closeup of a dark grey Mexican free-tailed bat, a bat with large ears and snout, hanging on a tree.
A man and a woman with binoculars watch as bats fly all around them.
A rolling vista with ample cactus, shrubs, and oak trees is backlit by a fading orange and pink sunset at Cibolo Bluffs.
A closeup of a cluster of blue curls, with periwinkle-colored blooms, bright green, curled leaves and long stemens dotted with yellow.
Staff give a talk to a crowd in front of Bracken Cave.
PARTNERS IN CONSERVATION Fran Hutchins of Bat Conservation International gives a presentation to visitors at Bracken Cave, which is co-managed by TNC in conjunction with Cibolo Bluffs. © Karine Aigner

What TNC Is Doing

Beyond managing and stewarding the preserve to enhance warbler habitat and protect flows into the Edwards Aquifer, TNC is preserving critical land around the largest maternal bat colony in the world. Cibolo Bluffs was initially established as a 1,244-acre protected parcel, but in 2014, over 1,500 acres (a portion of which was transferred to Bat Conservation International for their management) between the preserve and nearby Bracken Bat Cave were added to help protect the cave and its residents. From May to October, roughly 20 million Mexican free-tailed bats inhabit the cave. These beneficial pollinators emerge to forage for food each night, requiring significant open space for their flightpath.

Acquiring the acreage separating Cibolo Bluffs and the cave involved working with a coalition of public and private organizations, including the City of San Antonio, Bat Conservation International, the Edwards Aquifer Authority, Forestar, the U.S. Army and Bexar County. Visitors can now experience the bats’ nightly emergence at Bracken Bat Cave Preserve, which Bat Conservation International manages in conjunction with TNC staff. Ultimately, through land acquisitions and conservation easements, TNC and partners have helped protect over 5,000 acres of some of the most ecologically important land in the Hill Country along Cibolo Creek.

Cibolo Bluffs also continues to be a critical site for studies and surveys. Research conducted at the preserve by TNC staff and university students has ranged from testing effective techniques to remove invasive King Ranch bluestem to studying bird social behavior within family networks, as well as performing regular golden-cheek warbler surveys to determine any changes in the birds’ habitat or behavior.


  • The Frank Klein Cibolo Bluffs Nature Preserve is closed to the public. However, Bat Conservation International offers seasonal opportunities for members and non-members to view the bats as they emerge from nearby Bracken Cave. Please visit to view their current bat flight season schedule and book a reservation.

  • View a map of the Upper Cibolo Creek Conservation Area and its protected lands.