Arkansas’s Bats

Hidden Heroes of Pest Control.

By Chris Hancock

JAVARMAN.STOCK.ADOBE.COM

They swoop and dive at dusk, using their echolocation to detect their dinner. They patrol Arkansas farmlands and timberlands, hunting for pests that damage crops and timber. They loiter around lights in urban and rural areas, feasting on moths, beetles and mosquitoes.

Bats are often out of sight and mind, except maybe around Halloween. But there’s nothing scary about bats except what would happen if they disappeared. These nocturnal mammals are busy behind the scenes, crucial in our local and global ecosystems. They provide valuable services ranging from pollination to agricultural pest management and even eating those vampiric mosquitoes in your backyard.

“Bats are one of the primary pollinators of agave plants,” said Dan Taylor, senior restoration specialist at Bat Conservation International, based in Austin, Texas. Agave plants are used to produce tequila and mezcal. Bats worldwide play roles in pollinating several other major crops, including cacao, which is used to make chocolate.

In tropical environments, bats also disperse seeds from the fruits and plants they consume. In areas of logged rainforest, the majority of new plant growth is from bat dispersal “because the birds don’t like flying across those openings in the daytime … They’re hot and they’re susceptible to predation, but the bats will fly across those openings at night,” Taylor said.

In the U.S., almost all bat species are insectivores. Bracken Cave near San Antonio is home to one of the largest bat colonies in the world. The cave, managed by Bat Conservation International, is the summer home of more than 15 million migratory Mexican free-tailed bats, a species that also lives in Arkansas.

“They eat tons of insects every night,” said Taylor. “They’re intercepting moths that are crop pests … they’ll fly easily 100 miles a night out over the cotton fields and the corn fields feeding on insects.” This colony can consume over 147 tons of insects every night.

In Arkansas, “[Bats’] main role is as a predator of insects,” said Blake Sasse, nongame mammal and furbearer program coordinator at the Arkansas Game and Fish Commission. “All of the bat species we have in Arkansas are insect eaters and they eat a lot of them.”

Researchers at Boston University estimated that bats’ annual pest control services in the U.S. are worth at least $3.7 billion and potentially as much as $53 billion.

“The corn rootworm is a major crop pest,” Sasse said. This pest is “eaten by a species common here in Arkansas, the big brown bat.”

Three of Arkansas’s 16 species of bats are listed as endangered under the Endangered Species Act. A fourth species is expected to be added to the list soon and has been “proposed endangered.” The biggest threat to these species is White-Nose Syndrome.

Three species of bats were endangered in the 1970s…their populations are actually doing fairly well in Arkansas.

WNS, a fungal disease, damages the skin of bats. “It eats away at their wings,” said Lauren Marshall, an educator at the AGFC’s Witt Stephens Jr. Central Arkansas Nature Center.

Bats hibernate to survive the winter months. WNS disturbs bats during their hibernation, when their food supply is scarce. They burn precious fat reserves, struggle to find food and starve.

Multiple organizations are partnering in Arkansas to combat WNS. The work of the White-Nose Syndrome Response Team is documented on WhiteNoseSyndrome.org.

Historically, the greatest threats to bats in Arkansas have been disturbances, whether from WNS or humans, during the seasons when they are most vulnerable: hibernation and breeding seasons. The most deadly time to disturb bats or remove them from structures is during hibernation and breeding season when they have pups.

“You cannot remove bats from an area during a breeding season,” Marshall said.

During the breeding season, female bats form maternity colonies. When these colonies are disturbed, pups die because they cannot fly and feed independently. For four to six weeks, pups rely on their mothers for survival. Because bats typically produce only one pup per year, disturbances during the breeding season can lead to lost generations. Damaged colonies and threatened species require many years to recover.

When bats must be removed from an attic or structure, timing is critical. Marshall advises working with pest control services to ensure they are humanely relocated during the appropriate season. Guidance for humane bat removal and exclusion is available on the Bat Conservation International website.

While bats sometimes must be removed from problematic locations, there are benefits to attracting them to appropriate roosts. Bat houses provide artificial roosts and can attract bats for pest control services. A study on a Georgia pecan farm found that installation of bat houses to attract bats resulted in increased pecan production.

Installing a bat house can also aid efforts to relocate bats from structures. “You can put up a bat house and you have a better chance of success,” Taylor said. Bat houses can be purchased or assembled and installed with guidance from the AGFC or BCI websites.

“They do need to be built to certain specifications … and they have to be put up high enough where the bats feel safe from predation,” Taylor said.

The Arkansas Game and Fish Commission, Bat Conservation International and other organizations partner with private landowners to help protect bats from WNS, and disturbances during breeding and hibernation seasons.

There are thousands of caves in Arkansas, many on private land. The AGFC partners with landowners to install fencing at cave entrances to keep people out while allowing bats to come and go. “A lot of our endangered bats were endangered because people were bothering them during the winter when they’re trying to survive off the fat they’ve stored,” Sasse said. Installation of fencing has “been successful for a couple of our species.”

The AGFC has also worked with timber companies to cover abandoned water wells. These wells can be a safety hazard if not appropriately sealed, but they serve as critical habitats for some bats, providing cave-like conditions. By safely covering the wells, this effort eliminates safety hazards while providing habitat.

Another typical bat habitat is old trees with cavities from woodpeckers. “One of the most important things are big old trees,” Taylor said. “If a tree is not a safety hazard, allow it to remain standing.”

Multiple Arkansas bat species are endangered and numerous efforts are underway to protect bats and restore damaged populations. The public and private sectors, private landowners and individuals across the state all have roles to play, and past conservation efforts have proved successful over time.

“Three species of bats were endangered in the 1970s … their populations are actually doing fairly well in Arkansas,” Sasse said.

The Gray Bat’s recovery in Arkansas is progressing, partly due to fencing installation at cave entrances. “Their populations during the winter months would usually be around 200,000 bats in a couple of caves … but last winter, we had almost 1.2 million,” Sasse said.

Another species, the Ozark Big-Eared Bat, is also showing positive signs of recovery. The AGFC has been studying a population at Devil’s Den State Park since the 1970s. Gates were installed on several of the caves. “Those gates have been very effective,” said Sasse. “Usually, we’d see 50 to 100 there during the winter … last winter, it was over 300.”