The Depths We Go… to Study Bats

Bat Conservation International, TPWD Nongame and Rare Species Program, and Texas A&M University biologists and volunteers during bat surveys in the Texas Panhandle.

Texas bats are in danger. White-nose syndrome (WNS), a devastating fungal disease, is almost here. The disease is caused by a fungus that thrives in the cold environments where bats hibernate. Hibernating bats with WNS often display white fungus on their noses and other hairless parts of their bodies, including their wings.The fungus isn’t always visible to the naked eye, however, and usually is not seen on bats found flying or dead outside of their hibernacula or at their summer roosts.

White-nosed syndrome kills bats during hibernation by agitating their skin which causes them to wake up and preen. This expends their extremely limited energy reserves needed to sustain them for the entire winter and can eventually lead to starvation.

White-nosed syndrome was first discovered in New York in 2006 and has since spread westward towards Texas at a rate of about 200 miles a year. The disease is responsible for the deaths of nearly six million bats across North America. It is now just 170 miles from the Texas border in Arkansas and was just recently found in eastern Oklahoma. White-nosed syndrome does not affect humans.wns_map_20160216.jpg

Texas hosts 32 species of bats, more than any other U.S. state. Three species of Texas bats are known to be impacted by WNS and five others have been found with the fungus but exhibit no disease symptoms. The effects of WNS on the remaining 25 bat species in Texas are not known.

Many bats can live for 20 years or more and are very slow to reproduce. Stressors, such as introduced diseases like WNS, can result in significant population declines and push species towards regional extirpations or even extinction. The loss of bats due to WNS could have wide-ranging impacts to the ecosystem services provided by these night-flying, insectivorous mammals. From a human perspective, bats provide billions of dollars in pest control to agriculture annually through their insect feeding activities. Loss of bat populations would likely raise agricultural costs and increase pesticide applications.

Fortunately, the Mexican free-tailed bats, which roost in the millions in Bracken Bat Cave, Old Tunnel State Park, and the Congress Avenue Bridge in Austin, migrate instead of hibernate during the winter months. While this will likely shield them from the worst effects of the disease, Mexican free-tailed bats could still spread the fungus to more susceptible species across the western U.S.

Biologist examines a bat in a Texas Panhandle cave.

The Nongame and Rare Species Program at Texas Parks and Wildlife Department is partnering with Bat Conservation International and Texas A&M University to monitor bat populations and the spread of WNS. In early February 2016, biologists from both groups, along with some dedicated volunteers, met in the Texas Panhandle (Childress County) to test bats in several caves for WNS. Caves in this region of Texas are thought to contain environmental conditions (cold, humid) conducive to WNS infection.

Biologists searched caves for bats and when found, counted and swabbed individuals to test for WNS infection. The biologists are currently looking for additional caves in northern Texas to sample for the disease. This work is being supported by a grant through the U.S. Fish and Wildlife Service’s White-nose Syndrome Grants to States and the Pittman-Roberson Grants Programs. For more information about this disease visit White-nose


TPWD Receives White-nose Syndrome Grant Funding

Today Texas Parks and Wildlife received a federal grant for $21,618 to continue our research on bats and white-nose syndrome (WNS). U.S. Fish and Wildlife split nearly a million dollars across 35 states for similar research.

WNS has not been found in Texas, but it is knocking at our door. Since its discovery in New York state in 2006, it has moved toward Texas at an average speed of 200 miles a year. During it’s spread across the eastern states, an estimated 6 million bats have succumbed to the disease. TPWD will be focusing our efforts on early detection of WNS in susceptible areas.

White-nose syndrome is a serious issue and it is heartening to see such a large scale effort to combat it. Time to get to work!

See for more info on WNS.

Bat Monitoring in the Texas Panhandle

An acoustic monitor is turned on by Jonah, Dana & Rick.
An acoustic monitor is turned on by TPWD biologists Jonah Evans and Dana Wright.Rick Corbell from BCI is on the right.

The Texas Parks and Wildlife Department (TPWD) and Bat Conservation International (BCI) are collaborating on the fourth year of a project to monitor bats in the Texas panhandle.  This work is supported by a grant through the U.S. Fish and Wildlife Service’s White-nose Syndrome Grants to States Program awarded to TPWD.  The goal of this monitoring effort is to determine if the devastating disease known as white-nose syndrome (WNS), which has been steadily spreading across eastern North America, has made it to Texas. This disease is responsible for an estimated six million bat deaths and has the potential to do much more damage as it spreads westward.

White-nose syndrome affects hibernating bats in colder regions. For this reason, BCI and TPWD have focused surveillance efforts in the panhandle region of the state, where caves are most likely to host conditions suitable for the disease.

Jonah and Rick installing an acoustic monitor near the entrance of a cave.
Jonah Evans and Rick Corbell installing an acoustic monitor near the entrance of a cave.

This year, we have added a new element to the study – acoustic monitoring. We installed ultrasonic acoustic bat detectors at three of the highest priority caves in order to monitor when bats are active outside the cave. The acoustic monitors will remain in place, recording 24 hours a day, through March 2015.

Bats become unusually active during the winter when they contract WNS. The disease appears to cause individuals extreme discomfort, awakening bats from hibernation and forcing them to burn up limited fat reserves. The ultimate result of this disease-induced activity is that an infected bat may use up its fat reserves before the end of winter and die due to starvation.

The acoustic monitors will help identify if there is unusual winter activity at the targeted caves. Also, these monitors will help us learn more about natural winter activity patterns in Texas bats. In combination with temperature data loggers, we may learn whether bats become active during mid-winter warm periods – a behavior that may allow WNS-infected bats to feed mid-winter and avoid starvation.

For more information about this disease visit White-nose