Texas Old Tunnel Bats

Story and Photos by Mary Medland

There is a full moon out this evening in early September, but in spite of that, Bram Stoker’s children of the night—“Listen to them, the children of the night. What music they make!”--here in the Texas Hill Country are not cooperating.

Or at least most of them—there is an academic debate as to whether these “children” are vampires or wolves--are not dedicated to putting on the gala of a show that I have been anticipating.

Rats, as it were.

I’ve come here at 5:30 a.m. with Daryl Whitworth, assistant director of the Fredericksburg, TX, Convention and Visitors Bureau, expecting to see anywhere from 1.5 million to 3 million Mexican Free-tailed bats make their return to a tunnel that was originally built by the Fredericksburg & Northern Railroad before it was abandoned in 1942. Even while the trains were running through the tunnel, there were bats residing there, but at that time they hadn’t completely designated the place as their own exclusive bit of Lone Star state real estate.

Currently under the purview of the Texas Dept. of Parks and Wildlife, the Old Tunnel Wildlife Management Area is the smallest such area in the state, boasting a mere 16.1 acres. “These management areas were set up by Parks and Wildlife to support the interaction between humans and various species of wildlife, while maintaining the wildlife’s habitat,” says Whitworth, a sweet, well-bred giant of a man, who says “Yes, ma’am” effortlessly, has thoughtfully brought along coffee and a number of first-rate pulled-pork breakfast tacos that he picked up earlier this morning at the best taco bakery in town. Interestingly enough, that best taco bakery is owned and operated by Cambodian immigrants.

Bats are persnickety creatures, however, when it comes to timing their comings and goings. A small change in temperature or in the barometric pressure can alter the hour at which they leave in the evening and the time they return when light begins to have the upper hand. Whitworth and I have bats, for sure, swooping above us on their way to returning to the tunnel, but these are the stragglers—the great mass has already returned, and he and I probably are only treated to seeing a couple hundred or so. Still, it’s all pretty nifty, and the Old Tunnel has been a tourist destination for the past 15 years. Every evening from May through October—or before the cold snap zaps the Texas Hill Country—park rangers and volunteers welcome visitors an hour or so before the expected tunnel evacuation, explaining the lives of these often-misunderstood mammals—with faces that one wag noted, “only a mother could love”--and their place in the ecosystem.

“In the evening, the parking lot is crammed with cars,” says Whitworth. “I’ve found out that the people who are most reluctant to come here and who think that bats are completely icky are the ones who are the last to leave.”

Because the animals cannot fly as high as they need to rise above the trees near the mouth of the tunnel, they emerge in a continuous stream making two enormous counter-clockwise turns in order to get the momentum they need to reach those higher altitudes. Whitworth likens the emergence to a flowing river of little black bodies with the occasional albino bat making an appearance.

For those who are lucky enough to see the emerging spectacle, it’s apparently a great performance … one that typically takes anywhere from 30 minutes to one hour to complete. (Savvy would-be batters can call the Bat Hotline at 1-866-978-2287 for the estimated times of emergence and return.) Of course, once the bats leave the tunnel, they aren’t guaranteed that everything will be smooth sailing. Whitworth reports that hungry hawks are often seen sitting on tree limbs: As the bats emerge, the hawks will swoop out and collect a bat appetizer, main course, dessert and after-dinner cordial.

“The first item on the bats’ agenda is to find water … the Guadalupe River is only six or seven miles away,” says Whitworth, who, when not hauling travel writers around for a living, manages an 800-acre ranch he inherited from his father. “In addition there are a number of stock tanks, or earthen dams, that retain runoff rainwater.”

After slaking their thirst the creatures begin searching for food. If it’s a wet summer, the animals do not have to travel as far as they do during the course of a drought: Bugs are readily available. When the bats arrive from Mexico in May, many are already pregnant—females will give birth to a single “pup” in June. However, the Old Tunnel is not the best place for a maternity ward. “Because the tunnel is open on both ends, the temperature is too cool to give birth—even with the sweltering Texas summers,” notes Whitworth. “What the females do is to take up residence in what the biologists refer to as ‘nursery caves’ … there are lots of them around these hills. The caves are warmer and the temperature is more constant than in the tunnel.”

After giving birth, the mothers typically wait four to six weeks until the pups are able to fly. At this point the juveniles and their doting moms return to the Old Tunnel where they will stay until October before heading back to Mexico. At this time, the Old Tunnel bats are joined by their northern relatives who are heading for warmer climes.

Before leaving, Whitworth and I amble down a steep path that brings us to the same level as the tunnel’s floor. A little less than 100 yards or so yards away is the tunnel—looking for all the world like a beehive of swirling, buzzing bat activity.

It’s light now, and we are heading back to Fredericksburg, riding on a single-lane country road. Texas deer—considerably smaller than the deer Marylanders are familiar with--are feeding on either side of the road. (After dark, they do pose a threat to those returning from viewing the nighttime exodus.) But soon the bats will be bedding down for the rest of the day before heading out the next evening—off for food and drink—at the same time the rest of us are turning in for the night.

Ah, those creatures of the night!

Bat Facts

• Grab a dozen paper clips from your desk: They will give you a sense of how much Mexican Free-tailed bats weigh.
  
• When heading for Mexico, the bats can reach speeds of 60 m.p.h. and fly as high as 10,000 feet.
  
• If there has been a very dry summer, bats have been known to fly from the Old Tunnel to the Gulf Coast for water and to hunt, returning in 12 hours. That’s about a round trip of 400 miles.
  
• Bats drink water as they are flying, simply lapping it up as they fly by.
  
• The vast majority of the Mexican Free-tails diet is made of up of webworm moths, cornborers and cutworms—all of which are a bane to Texas farmers.

For more information, go to the Texas Parks and Wildlife Old Tunnel WMA site.

Rabies

There is some truth to bats being carriers of rabies. “They can carry rabies, and we do have the disease in this area,” says Daryl Whitworth. “Although the rangers handle bats, they also get annual rabies shots.”

As Whitworth notes, bats are primarily nocturnal creatures and even when they’re dwelling in old homes, typically they are not seen during the day. For a bat to be out and about in broad daylight is probably a pretty indication that the animal is sick or dying. Best to stay away from these animals.