The Texas Bats and Bridges Project
Cover | Abstract | Acknowledgements | Introduction | Methods and Results | Discussion |
Conclusion | Bibliography | Table 1: Statistical Results | Table 2: Texas Bat Species List | Home |

Abstract

The Texas Bats and Bridges study was designed to document bat roosting preferences in both bridges and culverts throughout the state. The study indicates that minor modifications to highway structures can maximize or minimize the potential for use by bats, and that less than 0.01% of Texas highway structures currently meet the day-roosting requirements for bats. In central, southern, and western Texas, there is a 62% chance that structures with suitable characteristics will be used by bats. The Mexican free-tailed bat (Tadarida brasiliensis) was found to be the most frequent bat species day roosting in highway structures. Bridge characteristics preferred by day-roosting bats were defined by a paired comparison study where bat-occupied and unoccupied bridge characteristics were statistically compared. A statewide evaluation was used to identify the distribution of highway structures used by bats. Day-roosting bats prefer concrete bridges and culverts with secluded locations such as crevices that are 0.5 to 1.25 inches-wide(1.2 to 3.2 cm), especially those that are 12 inches deep (30 cm), have covered tops, and are located in central, southern, and western Texas. Additional experiments further supported the results of the paired comparison and statewide evaluations. Bat colonies, even large ones, do not damage highway structures and water sources under roosts are not negatively impacted. Human health risks are minimized by educating people not to handle bats.

© Bat Conservation International, Inc., 2000. Absolutely no rights of distribution by sale or other transfer of ownership or by rental, lease or lending, preparation of derivitive works, or reproduction, in whole or in part, is granted. No text, graphics or photos may be downloaded and used on another Internet site, without express permission of BCI. To obtain permission or further information, send your request to bkeeley@batcon.org. BCI reserves the rights to actively protect against infringement.