Device allows researchers to “see” bat calls, ID bats
ALBANY, Ga. — Sitting in a dark swamp surrounded by fistsized spiders and the sounds of wild hogs rooting may seem like an unusual way to spend an evening. If you are looking for bats, however, the setting is perfect. And even though you might not see them, the bats are there, sometimes swooping right in front of your face in the dark, aiming to catch their next meal.
A listening device known as the Anabat confirms their presence.
The Anabat, a system designed to help identify and survey bats by detecting and analyzing their echolocation calls, is becoming a must-have device for wildlife biologists. Bats use echoloca- tion to navigate and find food. Humans are unable to hear most of these sounds but the Anabat picks them up and with the aid of an attached PDA displays them on a screen, making it possible to “see” the calls.
The displays are saved as files that can be analyzed by the Anabat program once biologists return from the field. Certain bats have distinctive call patterns that can be read by experienced bat biologists. However, some bats produce very similar sounds, making the calls of some species hard to distinguish.
While it is not always possible to identify each bat by its recorded call, biologists can often narrow the list of species to a few that call in the same frequency range and are found in similar habitats.
“The Anabat provides us with another tool for surveying and monitoring bats,” said Trina Morris, a wildlife biologist with the Georgia Wildlife Resources Division’s Nongame Conservation Section. “In the past, Georgia’s biologists relied on visual observations and caught bats with mist nets and harp traps to document populations.”
Morris used the Anabat and mist nets on a recent survey at Chickasawhatchee Wildlife Management Area near Albany for Rafinesque’s big-eared bats (Corynorhinus rafinesquii) and southeastern bats (Myotis austroriparius), both species of concern in Georgia. The results: Four southeastern bats captured.
“Bat trapping can be very difficult and time intensive,” Morris said. “The Anabat helps us to determine which species may be using a site and where we need to spend time trapping bats.”
Georgians can help conserve bats and other nongame wildlife, native plants and natural habitats through buying a wildlife license plate. They can also donate to the Give Wildlife a Chance state income tax checkoff.
Both programs are vital to the Wildlife Resources Division’s Nongame Conservation Section, which receives no state funds for its mission to help conserve wildlife not legally hunted, fished for or trapped, as well as rare plants and natural habitats in Georgia. Go to www.georgiawildlife.com for more information, or call Nongame Conservation offices in Social Circle (770-761-3035).
Visit http://users.lmi.net/corben/ anabat.htm#Overview for more information on the Anabat.
Bats, such as the Townsend’s Big-eared Bat, use echo-location to find their prey and navigate.