By Paul Davis
Outdoors Editor
As nightfall approached Monday evening, and the sounds of tree frogs and other creatures of the night began to fill the air, Mark Twain National Forest wildlife biologist Megan York-Harris waited impatiently.
York-Harris, along with U.S. Army Corps of Engineers rangers Eric Limanen, Eric Lemons and John Daves, was hoping to catch various species of bats over a small, hidden pond in the heavy timber of western Butler County.
Sometimes the plan works, while other times it doesn't, and occasionally an unintended species, like a flying squirrel or an owl, is captured instead.
While there are about 13 species of bats found locally, York-Harris said, one in particular, the northern long-eared bat, was the target during this trapping operation.
"The long-eared bat is listed as a threatened species," she said, "and we're looking for them because they are in serious decline."
Other listed species sometimes found locally are the Indiana bat and the gray bat.
That threatened status, York-Harris said, is the reason for the trapping effort in that area this summer.
"This is our (the Mark Twain National Forest's) next project area," she said. "Since they are a protected species, and they're found here, we need to protect the trees around any maternity colony."
Those protections, she said, help the Forest Service stay in compliance with the federal Endangered Species Act.
Last winter, York-Harris said, state officials found only seven long-eared bats during their cave inventory, while she found two during her trapping efforts.
The long-eared bats hibernate in caves, but in the summer, they move to forested habitats, and their populations have been hit especially hard by the white-nose syndrome, a form of fungus fatal to the species.
"Any bats in a cave environment can get it," York-Harris said.
While York-Harris has trapped bats locally every summer since about 2007, the partnership between the Forest Service and the Corps of Engineers started around 2012. Since both agencies do timber work and other projects on their lands, the bat-trapping partnership helps pool resources.
"I have the federal permit, and the Corps guys have the equipment and manpower," she said. "It's worked out really well."
On this hot and humid evening, the crew had placed four mist nets, each up to 18 meters long and up to 18 feet high, over the water before dark, knowing the location was their best shot to catch bats because they typically come to drink before feeding at night.
"Ponds provide a drinking source and are very productive regarding aquatic insects," York-Harris said. "After hanging out in the hot woods all day, the first thing bats want to do after they emerge at sunset is get a drink and eat."
Established bat trapping protocols require the nets to be checked every 15 minutes, and Monday's operation started out slowly. The first two checks turned up nothing in the nets, but the third proved successful, with three evening bats caught in the mesh.
A half hour later, two much larger red bats, the most common species, were captured, and by the end of the five-hour session, eight total bats were caught.
After each bat is captured, York-Harris said, several tests are conducted on them.
"First, we'll figure out if they're male or female," she said, "and we'll measure their forearm to help determine identification."
A check of the wing bones, back-lit by a bright light, also helps determine if the bat is an adult or juvenile.
"We also check the reproductive condition of females," she said.
Team members have to wear thick gloves during these tests because the bats tend to bite in self defense, though some do so more than others.
"The big brown bats have big teeth, and they're mean," York-Harris said with a laugh. A friend, she said, describes them as "chihuahuas with wings."
Each bat also is weighed, and those listed as endangered or threatened are fitted with radio transmitters.
"We'll put transmitters on them if we can," said York-Harris, "and some get leg bands" on their forearms.
The micro-sized radio transmitters, she said, weigh only .27 grams each and are attached between the shoulder blades, using a skin-bond adhesive.
"The transmitters last about two weeks," York-Harris said, before the adhesive dries up, and the device falls off.
The important thing about the transmitters, York-Harris said, is they allow her to determine the general location of the bat, which greatly aids in locating trees and areas where a maternity colony may be located so it won't be disturbed by logging or other agency operations.
For many people, York-Harris said, bats are a misunderstood creature with multiple benefits for the ecosystem.
"Bats are voracious insect eaters," York-Harris said. "They eat a variety of insects including moths, flies, beetles and mosquitoes."
Some bat species also are responsible for pollinating certain tropical fruit species.
Bats are nocturnal mammals (the only mammals able to fly), not birds, and hunt for their food using a sonar-like system.
"It's echolocation," York-Harris said. "They send out a signal, and it bounces off objects. That helps them find food and also to avoid hitting limbs and other things."
They're so sensitive, she said, the bats many times can avoid the tiny filaments of her nets at the last second simply by hearing the bounce-back sounds.
Bats also can swim well, she said, though she's not sure why.
Bats, however, are not aggressive toward people, nor will they chase them as many believe.
"They're after bugs, not people," said York-Harris.
"Everyone thinks they're all vampire bats," added Limanen.
While people are occasionally bitten, and bats can be carriers of the rabies virus, it's uncommon, and according to the Missouri Department of Conservation, only about one-half of 1 percent of bats carry rabies.
Another misconception is that many people believe bats are blind, York-Harris said, but that is "just an old wive's tale."
As June continues, York-Harris said, she plans to keep trapping. The team hopes to trap in five locations on the Poplar Bluff Ranger District, as well as five locations on Corps land surrounding Wappapello Lake, where timber operations are planned.
"The Forest Service (and other agencies) has a responsibility to manage for and mitigate effects to species of conservation concern and species listed under the Endangered Species Act," York-Harris said. "Forest management, such as timber harvesting and prescribed burning, could affect bats that roost in trees or on the ground, and it's important to make an effort to determine if these species are present in the area, and how we can avoid or significantly mitigate impacts on them."