Places We Protect

Eckert James River Bat Cave Preserve


Thousands of bats stream across a darkening sky.
Eckert James River Bat Cave This preserve offers spectacular views of millions of bats as they emerge to feed every evening. © Rich Kostecke/TNC

The Eckert James River Bat Cave is one of the largest bat nurseries in the country.



Just an hour’s drive northwest of Fredericksburg, in the heart of Texas, is an unassuming limestone cave that shelters one of the largest bat nurseries in the nation. About four million female bats inhabit the Eckert James River Bat Cave Preserve starting in May and running through September. In the Bat Cave, located southwest of Mason, many of these females give birth to a single pup in June or July that will then join them in flight at about five weeks of age. These pups will remain with their mothers until returning to Mexico in October.

The Bat Cave’s history is one uniquely tied to the Eckert family, beginning with W. Phillip Eckert, who purchased the ranch on which the cave was located in 1907. Throughout the early 1900s, he mined the bat guano in the cave and sold it to local farmers for crop fertilizer. W. Phillip’s son, Lee Eckert, continued his father's legacy of bat conservation and guano mining and left the site to his wife and children when he passed away in 1967.

In 1990, Richard Phillip Eckert and Virginia Eckert Garrett donated the cave to The Nature Conservancy (TNC) in honor of their father and grandfather, ensuring that the bats would be permanently protected. However, the donation came with one condition: the land around the cave must remain open to the public for enjoyment and education, as it had been for more than 100 years—and TNC is happy to continue to uphold this tradition.


Limited Access

Open Thursday - Sunday evenings from May 31 to Aug. 25; call 325-347-5970 to confirm.


Millions of Mexican free-tailed bats


8 acres

Explore our work in Texas

Rocky, limestone cave with a deep, black opening.
Bat Abode Eckert James River Bat Cave is home to one of the largest aggregations of warm-blooded animals in the world. © Jacqueline Ferrato/TNC

Why This Place Matters

Like all bat species, the millions of Mexican free-tailed bats at this unique preserve are an integral part of regional ecology. These warm-blooded animals are essential agents of seed dispersal and cross-pollinate many plant species to the benefit of local agriculture. Bats also control insect populations while scouring thousands of acres of countryside each night while searching for food. During these nightly excursions, each bat consumes close to its body weight in mosquitoes and other insects, including numerous crop pests such as cutworm and corn borer moths.

But none of their important ecological roles matter if roosting sites, like the Bat Cave, are disturbed or destroyed by humans. Such disturbances usually lead to either the total evacuation of a roost or the decimation of the entire bat population. Given the low birthrate of free-tailed bats, a single act of vandalism can destroy a colony. In fact, disturbances like these are largely attributed to having caused dramatic declines in free-tailed bat populations in some areas of the country.

Photos from Eckert James River Bat Cave Preserve

Experience the nightly emergence of millions of Mexican free-tailed bats at the preserve. Tag @nature_tx on Instagram with your photos when you visit.

A closeup of frenzied bats in mid flight, flapping around hundreds of other colony members as day turns to dusk.
More then 25 visitors sit in a semi-circle aroud the mouth of a limestone cave, watching intently as bats swirl out of the cave in a tornado of life.
A single black Mexican free-tailed bat roosts on a rocky, limestone wall, hanging upside down by its feet.
Bats flutter and emerge from a deep cave entrance dotted with green shrubs, soaring agianst a setting blue sky.
Hundreds of black and dark brown bats fly in a group.
Batastic The preserve not only protects the bats’ limestone cave, but also safeguards surrounding land for nightly foraging. © Jacqueline Ferrato/TNC

What TNC Is Doing

TNC and Bat Conservation International developed a cooperative management plan that prevents human entrance to the cave during maternal activity, controls visitation, monitors the bat population and protects the cave’s opening. Scientific research continues at the site, and the cave remains open to scientists throughout most of the year.

Each summer, the preserve serves as an educational platform to teach visitors about the bats’ value while watching them flutter and chirp around the mouth of the cave an hour or two before sunset. The stream of bats will initially fly in a large circle, low to the ground. As they gradually spiral upwards, the bats form a dark funnel of flying mammals, reaching several hundred feet into the fading sky. This densely packed “bat tornado,” or “bat-nado,” will last about an hour as they start the evening’s hunt. The free-tailed bats at the top of the spiral eventually break off, forming columns that stream out over the countryside.


  • The Eckert James River Bat Cave Preserve is open to visitors at scheduled times during the bat season. 

    For the 2024 season, the preserve will be open Thursday, Friday, Saturday and Sunday evenings, from May 31, 2024 to August 25, 2024 for bat emergence viewings. Learn more on our Open Nights event page.

    IMPORTANT: These open nights are dependent on a number of factors, so please call the bat hotline at 325-347-5970 before visiting for any weather/river flooding related closures, as well as to confirm the event start time; the bats emerge at varying times throughout the summer.

    We hope you can join us on one of these open nights and experience the natural wonder of the millions of bats who migrate there each year—it is truly a sight to behold!

  • IMPORTANT: Please call ahead of time (325-347-5970) to obtain local weather conditions and updates concerning the James River. This river is affected by flash flooding. Please note that the flood gauge normally reads 1 foot. Although higher clearance SUVs and pickup trucks are the preferred vehicles to cross the river, if the flood gauge is at 1 foot or below, most vehicles should be able to make the crossing. Use your own judgment based upon knowledge of your individual vehicle. Do not make the crossing if the flood gauge is above 1 foot or higher.

    Download PDF map and directions or see the directions below:

    1. Head south on 87 from Mason Town Square for approximately 1 mile, then turn right on FM 1723.
    2. Follow FM 1723 for approximately 2.4 miles, then turn right on FM 2389.
    3. Follow FM 2389 for approximately 4.8 miles. You will cross over the Llano River, then turn right onto James River Rd.
    4. Follow James River Rd. for approximately 8.3 miles to the preserve; pavement will end in a couple of miles. Continue on an unpaved road until you reach the James River crossing where the roadway fords the river. Drive slowly, as the road may be slick (but safe) to cross under normal conditions.
    5. Continue on James River Rd. past the river for approximately 0.5 miles; the road curves sharply to the left. The gated entrance to the Bat Cave Preserve is on the right at this curve.
    6. Follow Bat Cave Preserve Rd. to the parking lot.
  • Learn more about the Eckert James River Bat Cave and its residents in this informative brochure.