There are some 33 species of bats that call Texas home. Of these, possibly as many as 13 different species may be found in and around the Dallas/Fort Worth Metroplex. Some of these bats are very common in North Texas, and others not so much. It is even possible that a few of the bats that have been reported in North Texas actually only represent accidental or outlier records, as the documented range for these species is not typically thought to include Dallas/Fort Worth. Currently, the science on our North Texas bats is incomplete and some important questions remain.
As it turns out, there is still a great deal to be learned about bats in North Texas–and all across the state. There are many aspects of bat behavior and natural history that are not yet well understood. Bats engage in many complex and interesting behaviors, and they can be very sensitive to changes in their environment. There are a multitude of reasons to study these intriguing animals.
Fortunately, the bat population in North America–including Texas–is generally thought to be in relatively good condition. There are only a handful of bat species in Texas that are considered threatened or endangered. And of those, most have healthier populations outside of the state, and are not thought to be at risk overall. Still, many experts are concerned that a sizeable percentage of North American bat species are in need of conservation action in order to prevent dramatic population declines in the near future.
the three largest North American countries
The State of Texas if growing rapidly, and the boomtimes are creating situations that presents our resident bat species with a number of important challenges. The impact to the bat population from things like habitat loss due to rapid and expanding urbanization is not well understood. There is also evidence that the installation of wind turbines across large swaths of the state is contributing to the deaths of an inordinate number of bats. Pesticides are thought affect the health of bats via secondary poisoning that occurs when bats consume treated insects. And there are serious concerns about the spread of white-nosed syndrome, and how the disease might impact bat colonies across the state.
White-nose Syndrome – A potentially fatal fungal disease of bats characterized by white powdery fungal growth around the muzzles of infected animals. The disease is contagious and is spread through close contact in bat colonies. The fungus responsible for White-nose Syndrome can also be spread from location to location by people when the fungus transported on contaminated clothing and equipment.
Texas Parks and Wildlife Department has recognized the need for improving our understanding of bat behavior in general, and also how bats in our state are responding to the challenges presented by ever changing conditions. To this end, TPWD has recruited the participation of Texas Nature Trackers and the Texas Master Naturalists–with their cadres of citizen scientists–to help collect information about bats in the state. The project aims to document the distribution of bats throughout Texas to an extent never before attempted.
But bats are notoriously difficult to study. Bats tend to frequent places that can be challenging to access. Arboreal species are superbly camouflaged, making them extremely difficult to locate even in places where they are quite abundant. The study of bats is further complicated by the animal’s nocturnal habits, and because the majority of their active time is spent on the wing.
Texas Nature Trackers – An organization sponsored by the Texas Parks and Wildlife Department, and part of the state’s Wildlife Diversity Program. A citizen scientist effort that makes use of iNaturalist projects to track the status of wild populations of plants and animals throughout the state.
Texas Master Naturalist – A volunteer training program created through a partnership with the Texas Parks and Wildlife Department and the Texas A&M Agrilife Extension Service, which focuses on educating and engaging Texans in the conservation and management of the state’s natural resources.
Traditionally, the go to techniques for the scientific study of bats include roost counts and the live capture of individual specimens with mist nets. The information collected through both methods–while certainly valuable–is often limited in scope. New ways to study these animals, that are more informative and less intrusive, would be of great value.
That is where modern technology comes into the picture. Available to scientists now, are listening devices that can be placed in likely bat habitats. These acoustic monitors can be set to record the sounds bats make while they fly by on their nightly forays. Electronic bat monitors listen for and record the ultrasonic sounds produced by bat echolocation. The recordings are then stored as audio files on a memory card to be processed and analyzed later.
Echo Location – A biological sonar system used by certain animals–such as bats–to navigate and locate objects via the emission of sounds and interpretation of the returned echoes.
Ultrasonic – Of or involving sound waves with a frequency above the upper limit of human hearing.
Texas Parks and Wildlife has secured a collection of these ultrasonic monitoring devices to aid in their study of our state’s bat population, and Texas Master Naturalists have volunteered to do the work of installing and monitoring these recorders in different places around the state.
Thirty-seven Texas Master Naturalist chapters are participating in the study effort. Volunteers have been busy placing bat monitors in likely habitats around the state. Several of the participating Texas Master Naturalist chapters are located here in the Dallas/Fort Worth metroplex, and toward the end of May I was fortunate enough to have the opportunity to tag along with a couple of members as they setup a bat monitor in a remote part of Kaufman County.
During this field trip, I learn that the monitors must be installed with great care to maximize their chances for success. First and foremost, the listening device must be setup in a place that is likely to have a reasonable amount of bat activity. Locations with bodies of water and/or open grasslands will appeal to bats looking for prey. Prime locations will also be in proximity to likely roosts. In Dallas/Fort Worth, wooded areas with tall trees are good candidates. Similarly, certain kinds of human built structures may attract bat colonies. Installing units away from roads and other sources of extraneous noises is also an important consideration.
The bat monitoring devices are typically set to run from dusk to dawn. While active, the monitors listen for ultrasonic sounds of bat echolocation, and record them whenever they are detected. Bats use echolocation for navigation and to help find and capture the insects that they prey on. While in flight, bats will produce a series of ultrasonic pulses, and then listen for the sound waves to be reflected back. These echoes may be produced by anything in the bat’s environment, including obstacles to navigation and potential prey insects. Bats may even have the ability to form visualizations of their environment through their echolocation returns.
After about a week of data collection, the bat monitors will be retrieved and the recorded data processed. Analysis of the audio files, and identification of various bat species is done using a specialized software package. The software attempts to match the recorded audio with the most likely bat species. Different bat species produce different calls and sounds–depending upon where and how they use echolocation. But there can also be some overlap between species–a situation that sometimes prohibits the software from producing an absolute species identification. For this and other reasons–like stray and ambient noise–bat identifications produced by this software tool also include a confidence rating (low, medium, and high).
Afterwards, the processed data will be compiled into a report describing the different kinds of bat species identified. The collected data cannot reveal the number of bats in a certain area, but it can help produce a reliable survey of the types of bat species that are present. When data has been collected on private property, a special report for the landowner is produced as well.
This bat monitoring project is exciting application of modern technology. It makes research possible that would not have been possible just a few years ago. The Texas bat monitoring program began in 2024 and has continued into 2025. Each year, data will be collected from April through June. The project is expected to continue through 2027, and may be extended with the requisite success and support.
Bats of the DFW Area
| Name | Species | Roost | Description |
|---|---|---|---|
| American Perimyotis | Perimyotis subflavus | Buildings, Caves, and Crevices | A small, insectivorous bat that is a year-round resident in Texas. Common. Hibernates over winter. Ranges across most of Texas, with the exception of the far western portions of the Trans-Pecos. Fur is a yellowish-brown in color. |
| Big Brown Bat | Eptesicus fuscus | Trees, Buildings, Caves, and Crevices | A medium-sized, insectivorous bat that is a year-round resident in Texas. Common. Hibernates over winter. Range includes the eastern and western parts of the state, with a notable gap through central into south Texas. Fur color is typically a rich chestnut brown. |
| *Big Free-tailed Bat | Nyctinomops macrotis | Buildings, and Crevices | A large, insectivorous bat that is a year-round resident in Texas. Uncommon. Likely hibernates over winter. Ranges through the Trans Pecos, with a second population documented in the south-central part of the state. Fur color varies from reddish to dark brown, with a lighter underside. |
| Brazilian Free-tailed Bat | Tadarida brasiliensis | Buildings, Bridges, Caves, and Crevices | A medium-sized, insectivorous bat. The most common bat in Texas. These bats can be found all across the state. They are year-round residents in the eastern part of Texas and migratory in the western parts of their range. Fur color ranges from red to black. |
| *Cave Myotis | Myotis velifer | Buildings, Bridges, Caves, and Crevices | Largest of the Myotis in Texas. Insectivorous. Year-round resident in Texas. Common. Ranges across the north-central and south-central part of the state, and westward through the Trans Pecos. Fur color is typically a dull sepia with a lighter underside. |
| Eastern Red Bat | Lasiurus borealis | Trees | A medium-sized, insectivorous bat that is a year-round resident in Texas. Common, especially in the eastern part of the state. Migrates north or south with the change of season. Distribution is statewide. Fur is red in color. |
| Evening Bat | Nycticeius humeralis | Trees, and Buildings | A small, insectivorous bat that is a year-round resident in Texas. Common. Ranges across the eastern parts of Texas, with two additional populations documented further west. Fur color is dark–ranging from black to black-brown. |
| Hoary Bat | Aeorestes cinereus | Trees | A large, insectivorous bat. Common. Migratory. Males are more abundant in mountainous regions of the western United States, and female are typically found in the eastern part of the country. This pattern continues in Texas. The Hoary Bat ranges throughout the state when present. Fur color is a heavily frosted gray or brown. |
| *Northern Yellow Bat | Dasypterus intermedius | Spanish Moss, and Palm Trees | A large, insectivorous bat that is a year-round resident in Texas. Uncommon. Typically ranges in the southern part of the state, in a broad swath that follows the coast. Fur is silky in texture and is yellow-brown in color. |
| Seminole Bat | Lasiurus seminolus | Spanish Moss | A medium-sized, insectivorous bat that is a year-round resident in Texas. Common. Ranges includes the forested eastern-most part of the state. Fur color is a slightly frosted mahogany brown. |
| Silver-haired Bat | Lasionycteris noctivagans | Trees, Cavities, and Buildings | A medium-sized, insectivorous bat that is a spring-fall migrant in Texas. Uncommon. Ranges in forested areas throughout the state. Fur is brown or black with a frosting of white tips. |
| Southeastern Myotis | Myotis austroriparius | Trees, Caves, and Buildings | A small, insectivorous bat that is a year-round resident in Texas. Uncommon. The range of this bat includes the Piney Woods region of the state. Fur is wooly and brown in color. Underside fur is lightened with white tips. |
| *Yuma Myotis | Myotis yumanensis | Caves, and Buildings | A small, insectivorous bat that is a year-round resident in Trans-Pecos region of Texas. A narrow distribution swath follows the Rio Grande to the coast. Prefers desert areas. Common. Fur is a pale buff in color. |
IMPORTANT NOTE: Bats are a known rabies vector in Texas. Rabies is a serious and fatal disease if not treated in a timely fashion. The risk of infection from bats is relatively low, but caution is still advised. Bats should never be handled. Bites, possible bites, and incidental physical contact should be reported to the authorities and medical attention should be sought, if deemed necessary after an expert assessment. Follow this link for more information: Texas Health and Human Services.
