RETURN TO ARCHIVES


Wild Thing - Frances Fehribach
November 2003



Urban Bats

"Murcìelago"

The bat,
Elixir of shadow,
Dissolves in the air.
Without bats, there would be no night.
They give color to darkness
And awaken the frog
And they are the true lovers of the star.

-Federico Garcia Lorca


Every night in the summer, crowds in Austin converge upon Town Lake's banks below the Congress Street Bridge. They come to witness one of the greatest spectacles in nature - the emergence of approximately 1.5 million Mexican Free-tailed bats from cracks and crevices under the bridge.

The Congress Street Bridge bats comprise the largest urban bat colony in North America. When the bridge was reconstructed in 1980, it made for perfect bat habitat. While the city was alarmed at first, Bat Conservation International was able to educate the public and eventually endear them to the bats. The Congress Street Bridge is now a major tourist attraction.

But you don't have to travel to Austin to observe urban bats. In Texas and even in Fort Worth, Mexican free-tailed bats are abundant and have taken up residence in numerous bridges and parking garages.

Bats in parking garages are excellent tenants since they eat many insects in the surrounding area and keep pests away from the city. Mexican Free-tailed bats (Tadarida brasiliensis) in central Texas alone eat about 1,000 tons of insects every night in the summer.

An incidental benefit of these "parked" bats is that they make for excellent photo opportunities. On October 30, 2003 the Fort Worth Star-Telegram featured a small picture of bats in a crack of a parking garage. I was surprised because I had just taken similar pictures at another undisclosed location south of here. Needless to say, the professional picture in the paper was much better, but I was pleased with mine nonetheless.

"Just hanging out, man!"
These bats are roosting side ways in the crack, on each side, not actually hanging upside down. Small Velcro-like hairs on their toes enable them to adhere to rough surfaces such as concrete.

Over the years, I have seen several fantastic emergences from caves and the Congress Street Bridge, but earlier this month was my first time to watch a parking garage emergence. It was especially chaotic because at the same time, hundreds of grackles took off and headed to a nearby roost. The sky was alive with sights and sounds as the loud grackles called and flew with the bats. Shoppers heading for their cars observed the sight with wonder, not fully understanding what was happening - that these creatures were going through their usual nightly routine.

There was something admittedly comical about how the bats emerged from various cracks - they looked somewhat like drops being squeezed from a package of ketchup!

"Is it safe to come out now?"
A bat emerges from a crack in the parking garage.

"Out for a night of fine dining!"
Notice how the tail extends from the tail membrane, hence the name "free-tailed."

Very early the next morning, I came to watch the bats return to the roost. Now, I have never been fortunate enough to witness bats returning even to a cave in the morning, so this was something new for me. It was also somewhat comical. As one bat returned, it would spiral several times and then head straight for the crack. The funny thing is, sometimes they missed! Then they would have to spiral around a few times and try again. Sometimes it took several tries before they finally made it.

When I later looked carefully at my very amateur photos, I discovered that when approaching the roost, the bat had its "landing gear" up - that is, it was flying upside down!

Is it a megabat, a microbat, or an acrobat? This microchiropteran species member approaches the roost à la somersault. Pedestrians in the crosswalk will just have to wait!

After all this, I bought another, supposedly better camera, and returned to the place where I had observed them. Unfortunately, it was too late - they had already gone to Mexico.

The sub-species of Mexican Free-tailed bats that lives in Fort Worth, however, is thought not to migrate or hibernate, but to slow down activity. With a bat detector, I have not picked up any activity in the winter months. But you never know! With some nice weather, maybe they will come out to eat!

For more information, visit Bat Conservation International's web site, www.batcon.org.

"Murcìelago" from Federico Garcia Lorca, Collected Poems, edited by Christopher Maurer, translated by Jerome Rothenberg; published by Farrar, Strauss and Giroux 2002.

Factual information from Texas Bats, by Merlin Tuttle.

All photos copyright, Frances Fehribach



Cross Timbers Chapter, Texas Master Naturalist, Inc.   9601 Fossil Ridge Rd.   Fort Worth TX 76135

Site design & content Cross Timbers Chapter, Texas Master Naturalist, Inc.  All rights reserved.  Contact Webmaster.