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Hill Country Bat Information

The map below provided by Bat Conservation International (BCI) shows all known colonies of the Mexican Free Tailed bats as dots and a 50 kilometer buffer around each site that reflects a potential foraging area.


Energy that endangers bats not 'green'


The Texas Hill Country, home to the world's largest remaining bat colonies, has been the focus of proposals for wind energy projects. We are deeply concerned about the potentially serious consequences to Hill Country wildlife — ironically, from an energy source commonly promoted as "green."

Several of America’s leading wind energy producers — Florida Power and Light, PPM Energy and AES SeaWest — have investigated large-scale wind energy facilities in the Hill Country, and we applaud them for avoiding that area because of the exceptionally high risks to wildlife.

At least a dozen caves and several bridges and tunnels harbor huge maternity colonies of Mexican free-tailed bats, with a total population estimated at close to 100 million. These bats consume about 1,000 tons of insects nightly, feeding on Texas’ most costly crop pests. Mexican free-tailed bats in the Hill Country perform vital ecosystem services that, if lost, could be extremely costly.

Clearly, these bats are invaluable to Texas agriculture, not to mention tourism. Austin’s Congress Avenue Bridge colony alone generates about $10 million in tourism annually.

Unfortunately, recent reports from Oklahoma suggest that Mexican free-tailed bats, especially pregnant and nursing mothers, are among America’s most vulnerable species when it comes to being killed by wind turbines.

Other sensitive areas within the Texas Gulf Coast are also of deep concern. The Gulf Coast is of primary importance for migrating wildlife. The area is geographically situated to serve as a continental funnel for the most populous and diverse array of migrating songbirds, shorebirds, raptors and others. Most of the birds that breed east of the Rocky Mountains and the Canadian Arctic pass through this area. The Laguna Madre alone supports approximately 80 percent of the global population of wintering Redhead ducks.

Although Texas leads the nation in installed wind power-producing capacity, including some 1,400 turbines, to our knowledge, no peer-reviewed monitoring studies of wildlife impacts have been mandated by the state or conducted at existing facilities. External scientific studies on impacts of wind energy development in Texas are desperately needed.

Studies from other states suggest problems for bats that, if not soon remedied, could threaten entire species through cumulative impacts. Habitat-related impacts from wind energy development are largely unknown, but they also could prove serious if facilities are sited inappropriately.

While we feel it is the private landowner’s decision whether to participate in wind energy development, overarching concerns for wildlife create a need for caution. Development of wind energy in areas of high wildlife usage, such as certain Hill Country and Gulf Coast sites, should be avoided until credible scientific documentation of threat levels and solutions has been gathered.

We applaud AES SeaWest’s recent conclusion (in a letter to Gillespie County community leaders dated Aug. 8): "We have learned that there are several sensitive species and their habitats that are known to occur in the area, and that these sensitive species and bat colonies could be incompatible with large-scale wind energy. As a company that places an emphasis on environmental stewardship and preservation of wildlife, we are concerned that the site may not be suitable from a wildlife standpoint, and is therefore not a good use of our development resources."

The environmental consciousness demonstrated by AES SeaWest in the Hill Country must be emulated throughout the wind-energy industry. Companies that put wildlife at risk cannot claim to produce "green energy."

Merlin D. Tuttle
and Thomas H. Kunz

Merlin D. Tuttle, Ph.D., is president of Bat Conservation International. Thomas H. Kunz, Ph.D., is a professor and director of the Center for Ecology and Conservation Biology at Boston University. Their statement is endorsed by Anne Brown, executive director of Audubon Texas and vice president of the National Audubon Society; David Newstead, president of the Coastal Bend Audubon Society; Gina Donovan, executive director of the Houston Audubon Society; and Carter Smith, Texas state director of the Nature Conservancy., 4 November 2007

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