The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Wednesday, July 25, 2001

Bats Any One?
Carol Cullar, Eagle Pass News Guide, July 25, 2001, © 2001, 2003

I’ve never seen anyone who didn’t scream when they unexpectedly encountered a bat! They’re hairy beasts! They fly in your face! Then there are those far south of here that have fangs and feed on blood! Yeck! There are rumors that bats carry rabies and are simply lurking in the night to attack humans! Not so!

Somehow in all the myth, the facts are completely forgotten. Bats are not a health or safety concern. Bats make up one fourth of the mammals on this planet. Only the smallest percentages have been found to be rabid. There are over 1000 species of bats. They come in many different shapes, sizes, colors, and habitats. Different species of bats eat different foods: insects, fruit, pollen, and small animals are among the dietary preferences of some species. About 70% feed on insects; 20%, on fruit and nectar from blooming plants. Others feed on small animals and fish. There are only three species of bats that feed on the blood of other animals (usually cattle)—the so-called “vampire.” They do not suck blood; they lap it after making a small incision and only need about two tablespoons a night. Vampire bats live far to the south in Central and South America. (These bat facts came from a quick websearch.)

Eagle Pass is fortunate that we are in the migratory path of the Mexican Free-tail bat. One of the largest bat caves on earth is located in Mason County about 200 miles northeast of Maverick. These bats migrate back and forth between the cave and warmer climes in Mexico We’re fortunate because one small gray bat, weighing about an ounce, can eat 600 mosquitoes and small insects an hour.

Rather than spray their pecan orchards with what over the years amounts to tons of insecticides that get into the soil and the water table and kill every insect they touch (including the good guys: ladybugs, lacewings, and preying mantis, to name but a few) some pecan growers are looking toward natural eradication of the casebearer moth that can devastate a pecan crop. And how can they do that? Invite a family or two of bats to take up residence in the orchard, of course!

Just this past week Worick Farms consulted with the Rio Bravo Nature Center on how to build bat houses. Even a small structure 14” x 12” x 6” can house as many as forty bats. Let’s see now: 40 bats at 600 mosquitoes or moths an hour for eight hours every night . . . Well you get the picture! And in a community where mosquitoes DO carry disease, it would behoove us to be kinder to bats!

Bat house construction is extremely easy and economical. A rectangular box with a small bottom entry slot about ¾” in width and running the width of the box is ideal. The interior of the box should be routed with shallow horizontal grooves (for toe holds) every 3”. The roof can have a simple slant with a slight overhang for shade and four, tiny ¼” air holes drilled in the walls right below the roof. Seal all the seams and that’s it! You have a bat house!

Now there are some tricks to use to actually get the bats interested: 1) the box has to be in the shade in this part of the country. 2) The bottom of the bat house, where the narrow door is, needs to be at least 13 feet off the ground. 3) In this climate and with our heat, the box needs to be painted white to control the interior temperature. (This could be why your commercially purchased bat house never worked in this part of the country! Bats like it warm, but are driven off by temperatures over 98 degrees.)

How do you roll out the red carpet for your new tenants when the house is finished? You’ll have your best luck if you set up your house about six to ten feet away from where you have already seen bats—on a pole or tree or under the eaves.

Want to get them out of your walls without filling the walls with poison? All you have to do is sit out one evening armed with a caulking gun and wait for them to exit the walls or eaves, then an hour after they have departed for their night of hunting, simply caulk the seams between roof and walls. Any space wider than ¾” is an open door for a bat! Fill the gaps and your home is free of bats in the walls, but remember those little furry guys are working hard all night to rid our community of mosquitoes, so have a new bat house waiting for them when they return!

Monday, July 16, 2001

This Special Place
Carol Cullar, Eagle Pass News Guide, July 16, 2001 © 2001, 2003
executive director Rio Bravo Nature Center Foundation, Inc.

Birds? Bats? Snakes? Frogs? Mountain lions and bobcats, javelina and hornytoads! Oh, my! What do we have here? What creatures besides people share this corner of Southwest Texas with us? And what makes this place, our little bit of earth, so special?

Maverick County and this surrounding region of Texas Brush Country belong to a larger area that shares the same climate, geography, plants, and animals. This sharing of similar lifeforms is called a biosphere. Our particular region, the Tamaulipan Biotic Province, consists of two subdivisions: the Tamaulipan matorral (higher forested regions in Mexico) and the Tamaulipan mesquital, which include South and Southwest Texas and Northeastern Mexico.

This biosphere, consisting of some 54,600 square miles, is the size of Illinois. This marvelously important region is home to more than 600 vertebrate species. More than 485 of those species are birds. There are in excess of 1,100 species of plants. Of the 423 species of butterflies in the state of Texas, more than two thirds of them are in the Tamaulipan Biotic Province.

In the Audubon Sabal Palm Grove, more than 900 species of beetles alone have been identified. Located in the far northwest corner of this region Maverick County isn't necessarily home to all the same species found along the Coast, but still thrives with varied plants and animals

This Tamaulipan Biotic Province is the most biodiverse in all of North America AND the most threatened.

Just within the last 30 years this region has undergone vast environmental change. Some of those changes are not caused by humans; most of them are. Humans cannot be blamed for the drought. All the other drastic changes in the region are the result of human influx into what was once a vast thicket of xeric [adapted to very dry habitat] vegetation fed by the fifth longest river in the U. S.

The Rio Grande continues to support these diverse species of animals and birds, but the last 30 years have in the name of progress and agriculture seen extreme changes to this already dry habitat: water diversion; flood control; brushland clearing; population growth; agricultural growth; contamination of water and soil with pesticides, herbicides, and fertilizers; removal of carrizo from riverbanks, and more recently the proliferation of factories dumping pollutants into the river.

Habitats for the ocelot and jaguarundi, as well as other threatened and rare species, have been reduced to small isolated islands of brush along streams and rivers. When this chaparral thicket is broken into non-contiguous pockets of brush, it is no longer usable as a migratory corridor for many species. At some point the expansion of human habitation begins to irrevocably damage the irreplaceable habitat of our fellow species.

What's to be done? Whose problem is this? In whose hands lie the solution? Can these issues be left strictly in the laps of large land owners and agriculturists? Local governments?

Is there one single factor that will make the biggest difference for the good of man and beast throughout this region?

Is there anything that I can do as an individual to assure that this precious place and all its inhabitants in all their richness and biodiversity will be here for my children and their children?

The answer is “yes.” And that answer is education, awareness, and involvement. Become aware of what is being done in your area to protect threatened species. Can you name and identify the threatened species inhabiting Maverick County? Are your children being taught to identify all the plants and animals in this region? What are the state laws concerning the protection of songbirds and bats? Are you aware of the status of the Rio Grande? What is its future? Get involved in recycling and water conservation. Become a participant in the efforts to preserve our native plants and animals.