Tim Dobbs looks forward to Friday nights in June and July, when he makes carefully planned drives along desolate, darkened roads.
“It’s a nice, early evening trip,” he said. “You get to see deer, snakes – all kinds of wildlife.”
His primary mission is to listen for sounds rarely heard by humans: the high-frequency calls of bats moving across the night sky.
The Martinez man is part of a statewide team of volunteers who use high-tech surveillance gear to monitor bat movement along 35 widely scattered routes.
The equipment, called Anabat, can identify and count bats by analyzing echolocation calls they use to navigate and find food.
The device lowers the frequency of the sounds to make them audible to humans – and records the data as part of an effort to learn more about one of nature’s most misunderstood species.
“It comes in as little chirps and squeaks,” said Dobbs, who drives two 30-mile routes with his bat detector and antenna attached to his truck.
“We run each route twice a month, for two months,” he said. “One is from Ridge Road to Grovetown, and the other is in Burke County, going toward Millen.”
Georgia is home to 16 species of bats, and most – if not all – are imperiled in some way.
The Anabat project underway in Georgia and many other states is part of an effort to compile reliable population and migration estimates.
“We started officially with volunteers last year, after it took us a few years to get the routes mapped out,” said wildlife biologist Trina Morris, who leads bat research for the Department of Natural Resources’ Nongame Conservation Section.
Among the bats found in Georgia are the eastern red bat, which is often a solitary creature. They can sometimes be seen during the day roosting and might resemble a dried-up leaf on a branch.
A fairly common species is the big brown bat, which roosts in small colonies and can sometimes be found in attics.
“We’re also starting to see Brazilian free-tailed bats,” Morris said. “That’s one of the only species that is likely to be increasing in numbers, because temperatures here are not as super cold as we used to have.”
Among all those bats are plenty of questions related to population, migration routes and mortality. Some of those questions could be answered over time through data collected through the Anabat project, Morris said.
“We plan to be doing this for many years,” she said.
Bats sometimes get a bad rap, she said, but beyond all the folklore they are important creatures trying to survive in a changing world.
“All of our bat species eat exclusively insects,” she said. “In general, bats can eat half their body weight in insects in just one night. They forage a lot, especially nursing females with young.”
They are also fragile in terms of their needs and ability to adapt.
“They are more easily wiped out than a lot of species,” she said. “They require a lot of things often impacted by man.”
Changes in water quality, for example, can wipe out insects needed for bats to survive. Bats are also sensitive to pesticides and direct loss of habitat.
Of particular concern is the recent discovery in Georgia of white nose syndrome, which has devastated some bat populations in the Northeast.
“There is a lot more we need to know, and surveys are sometimes the only way to document what we have,” Morris said.