One of the most distinctive natural attractions in Texas is the Old Tunnel State Park located between Comfort and Fredericksburg on Old Highway 9.
From May through October, three million Mexican free-tailed bats swirl out of the abandoned tunnel around dusk like a dark tornado. Most bats exit out the south end of the tunnel, spiraling in a counter-clockwise path to gain enough height to clear the nearby trees. On many evenings, hawks can be seen hovering overhead to grab a bite as the bats emerge upward.
Park rangers say these bats travel southeast towards the Guadalupe River while bats who exit from the north end go towards the Pedernales River. They go immediately to water and then disperse into smaller groups for feeding. The bat colony eats over 25 tons of moths and mosquitos covering an average of 25 to 30 miles per night before returning before dawn. The first emergence of bats are female and young and it lasts about 15 minutes. After a pause, the males fly out next.
The area is supervised by Texas Parks and Wildlife and is the smallest state park in Texas.
Although there is no charge to see the bats from the Upper Viewing Area, near the parking lot, a 30 minute to an hour educational presentation and closer view for a limited number of people is available at the Lower Viewing Area from Thursdays to Sunday.
“The upper viewing area, located adjacent to the parking area, is open nightly for use by the general public,” the Texas Parks and Wildlife website states. “The scenic view from the upper viewing area allows visitors to experience the rugged beauty of the Texas Hill Country. Many bicyclists, motorcyclists, and car clubs stop at Old Tunnel to enjoy this view. Bats are best viewed from this area during August and September, when bat emergence times are earlier and more light is present. Fantastic views of red-tailed hawks feeding on emerging bats can also be seen from this area. No fees are charged and no passports or permits are required.”
“A close-up view of the emergence is one of the most unique experiences in nature. The flapping of millions of tiny wings is usually audible and often creates a light wind that can be felt by visitors in the lower viewing area…An educational program is given about bats, with an emphasis on the fascinating life history of the Mexican free-tailed bat (Tadarida brasiliensis mexicana).”
From San Antonio, go IH-10 West past Boerne into Comfort. Take Highway 473 North for five miles. Keep going straight on Old Highway 9 when the road veers to the right toward Sisterdale. At almost 9 miles, you will find the parking lot and mound of large rocks on top of a hill. If you get there right before dusk, you will usually see hawks flying around in circles waiting for the bats to come out.
The tunnel was part of the Fredericksburg and Northern Railroad and was abandoned in the 1940s.
There is a half mile nature trail to the viewing area where hill country wild life and vegetation are in abundance, including several species of raptors.
“Seats are filled on a first-come, first-served basis with a maximum seating capacity of 70 visitors. Reservations are not accepted. The activity tour fee for the lower viewing area is $5 per person ages 4 and up. Due to the bat’s sensitivity to noise disturbance, children age 3 and under are not allowed at the lower viewing area. They do not accept the Texas State Parks Pass or the Bluebonnet Pass. These passes cover the entrance fee to state parks, but not activity and tour fees. They also do not accept Limited Public Use and Annual Public Hunting Permits. They accept cash or check only. This park does not have cash on hand and is not able to make change; please bring the exact amount of cash for payment.
Reservations are not taken, except for special group tours on Monday thru Wednesday evenings.
Hours: Open year-round from sunrise to sunset; from May thru October, upper viewing area open seven nights a week and lower viewing area open Thursday thru Sunday from 2 hours before sunset. The viewing is handicap accessible.