Katherine Gividen has always loved bats, so when the Louisiana Department of Wildlife and Fisheries started looking for volunteers to help monitor bat colonies in the state, she immediately signed up.

“It took a while to get started, but I was persistent,” said Gividen, who really can't explain her infatuation with these creatures, which many liken to flying rats.

Gividen's bat love, and that of other volunteers, is helping the LDWF monitor bat populations to determine shifts in species distribution and how they're faring in numbers due to changes in habitat and the environment. They're also trying to detect white-nose syndrome in bat populations in the state.

The disease, said Nikki Anderson, wildlife disease biologist with LDWF, has wreaked havoc on hibernating bat populations across the U.S. The deadly disease, so named because of the white fungal growth on infected bats’ muzzles and wings, has been confirmed in 36 states and seven Canadian provinces. So far, neither the disease nor the fungus that causes it has been found in Louisiana.

In addition to the disease, bats are under threat from climate changes, habitat destruction and hunting for sport and meat.

There are 1,000 species of bats worldwide with 40 species in the U.S., and more than half of the species in the U.S. are in severe decline or listed as endangered, according to The Nature Conservacy.

“Drastic declines in bat populations threaten regional extinction for some species, such as the little brown bat, once the most common species of bat in North America,” Gividen said.

Most bats in the United States and Canada feed on insects, like mosquitoes, and those that ruin farmers’ crops. One colony of Brazilian free-tail bats can consume thousands of pounds of crop-damaging pests in a year, saving U.S. agriculture an estimated $3.7 billion dollars annually in pest control, according to LDWF numbers.

Gividen couldn't wait to do her part. So after attending a training session, she equipped her Subaru with a microphone stand, ultrasonic microphone, a Song Meter Acoustic recorder, a GPS unit and two plastic vials containing memory cards to preserve the data for each survey.

Starting at exactly 45 minutes after sunset, she began her 16-mile route.

“You cannot drive over 20 miles per hour," Gividen said. "If you do, the wind will interfere with the recording.”

The antenna atop her car recorded the sounds a bat produces when it is looking for food. The bat's high-pitched pings and clicks bounce off objects in the environment and return to the bat — a phenomenon called echolocation. The reflected sound allows bats to identify prey and capture it.

Echolocation frequencies range from 20 to 200 kilohertz, and each species emits a unique frequency. As a result, scientists can use these acoustic devices to identify a species’ presence and distribution without having to capture or see a bat.

In her first two consecutive night bat rides, each of which took about two hours, in West Feliciana Parish, Gividen recorded 231 bats representing seven species.

“My monitor was lighting up like a Christmas tree," she said. "I couldn’t wait to see what was being recorded.”

Gividen said she enjoyed it so much, she signed up to do more routes.

“I absolutely love it. It’s exciting, and you are out in nature on these secluded country roads. I’ve seen wild turkey and feral hogs, and listened to the different frog calls, and every time I see the green lights lighting up signaling bat calls, it’s like an adrenaline rush,” she explained.

In addition to West Feliciana, Gividen has driven routes in East Feliciana, Livingston and Cameron parishes.

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“Katherine is our bat-monitoring rock star,” said LDWF's Anderson. “She’s helped us with so many bat routes, and we couldn’t have gotten all the data that we have now without her.”

But Gividen goes beyond getting behind the wheel. Her other activities would be the stuff of nightmares for many.

To take part in bat surveys, Gividen creeps through culverts and under bridges to actually put eyes on bat colonies. 

"We crawled through a culvert on the side of the highway and found a colony of southern myotis bats under a manhole cover," Gividen said. "Under a wooden bridge, we found some Mexican free-tailed bats."

She recently helped lead a workshop on building bat houses with Louisiana Master Naturalists of Greater Baton Rouge in hopes of creating more bat habitats, a project of LDWF, Dr. Brandon Hedrick and the LSU medical school.

Anderson said more volunteers are needed to help with bat projects, including acoustic monitoring, for which LDWF supplies all training materials.

The next monitoring season in Louisiana will be in June and July, during bats' maternity season, and in late November to mid-March, she said.

“We’re one of the few states that do monitoring in the winter because we have insects flying then and the bats are out eating,” Anderson said.

Resources:

To purchase a bat house, email Lyndon Bourgoyne at lyndonbourgoyne@yahoo.com.

Louisiana Department of Wildlife and Fisheries, ldwfwildlifehealth@wlf.la.gov or (225) 765-5030

batconservation.org

 


Bat facts

from The Nature Conservancy

  • There are 1,000 species of bats worldwide with 40 species in the U.S.; more than half of the bat species in the U.S. are in severe decline or listed as endangered.
  • Though small in physical size, bats make up 20% of the world’s mammals.
  • Most bats have one baby (called a pup) a year; bat mothers can find their babies among thousands of others by their unique voices and scents.
  • Bat droppings, called guano, are rich fertilizers, with high levels of nitrate and ammonium.
  • Mexican free-tailed bats can reach speeds up to 100 mph, making it by far the fastest mammal on Earth, according to researchers at the University of Tennessee.
  • North American’s largest urban population of Brazilian free-tailed bats (formerly called Mexican free-tailed) live beneath the Congress Avenue Bridge in Austin, Texas, which is home to more than 1.5 million bats.

This column is supplied by Louisiana Master Naturalists of Greater Baton Rouge, which seeks to advance awareness, understanding and stewardship of the natural environment. For more information, email info@lmngbr.org.