First aquatic Anabat route in Georgia a success
By: Trina Morris, DNR Wildlife Biologist
After the announcement last spring about the opportunity for volunteers to run Anabat routes across the state, I received an incredible amount of emails. All the routes were spoken for in a few days! But many emails and phone calls came from the metro Atlanta area. People wanted to help yet we had no routes near the city. Why not?
The answer is there just aren’t roads safe and suitable for the survey. There are plenty of bats in Atlanta. But we need roads that are relatively straight and can be driven at 20 mph after dark. That combination is hard to find in a metro area.
I had been considering doing some aquatic routes in Georgia, however. Other states run routes on waterways using canoes, rafts and johnboats. Researchers have even strapped bat detectors to cargo ships. But those routes add a new list of issues. Still, thinking about the “bat gap” in Atlanta, I thought the Chattahoochee River might be a good place to try. There’s certainly a lot less trouble with traffic after dark and I was sure there would be bats on the river.
I pitched the idea to Allyson Read, biologist with National Park Service’s Chattahoochee River National Recreation Area. She was excited. Other than one short-term survey years before, they had no information about bats using the river.
After some paperwork and discussion about the best area to survey, we were set to go.
The night of May 20, recreation area officer Sean Perchalski had our boat ready at Abbotts Bridge, where the ramp was caked with mud from recent heavy rains. The Anabat, a device used to record bat calls, was in a makeshift case on the boat’s bow, perched on a tripod and secured with a camera clip, ratchet straps and duct tape.
I wasn’t sure if it was going to work but we had to try. Allyson snapped a few photos and Sean maneuvered the boat into the middle of the river.
We motored down to Medlock Bridge to begin the 10-mile route. The Anabat looked secure enough; I didn’t even notice a wobble. The night was warm and humid but the river was clear and as soon as we turned on the detector we picked up a bat. We headed upstream on the route, going what seemed like a fast 20 mph. I was excited that we would be able to compare the calls so closely to those collected by a car or truck. Several bats flew right over the detector, and I knew we were getting some good calls.
Then the fog rolled in. I was thinking it was getting pretty hard to see and that Sean must know this river like the back of his hand when he asked me if he could slow down. He agreed the fog was a problem and we wouldn’t be able to go as fast as hoped. That’s what I had expected so I wasn’t worried. I could see the lights on the detector indicating that we were still picking up bat calls.
We slowly worked our way up-river, startling great blue herons, roosting black vultures and possibly a family of owls. We passed houses, remnants of old industrial sites, some newly downed trees and a few rocks that Sean deftly avoided. Finally, at just after 10 p.m. we arrived at our ending point near Shake Rag. Sean shut off the boat for a minute to give our ears a break and we listened to a few more bats being picked up by the detector.
Although the route was finished on the way back we collected calls just to see what would get.
The next day, I was eager to get to the office and download the results. I was concerned that noise from the boat motor and the wind might reduce the quality of the calls and make them hard to identify. But I was pleasantly surprised when I opened the files and saw so many good calls!
A preliminary check showed likely calls of red bats, tri-colored bats, big brown bats, Mexican free-tailed bats and silver-haired bats. Bat call identification is tricky and there’s no fast and easy way to do it. There’s still a lot of work to do on analyzing the Chattahoochee route calls as well as those recorded over the last few years. Yet the information we’re collecting is essential to understanding how bats species and numbers of bats in Georgia are changing over time.
The discovery of white-nose syndrome in Georgia this winter makes efforts to gather information about our bats more critical than ever. Bat data is sparse throughout North America. This group of animals was largely ignored and treated as pests in the past. Plus, bats are much less visible than birds since they’re out at night and humans can’t hear their echolocation calls.
But opinions about bats are changing and people are beginning to understand what an important role they play http://www.fort.usgs.gov/Products/Publications/23069a/23069a.pdf. The Georgia Anabat project http://www.georgiawildlife.com/AnabatProject is one part of a larger movement across North America to find out more about our bats before we lose them.
And this route in the middle of metro Atlanta, on a river long loved and long abused, is an important part of that movement.
Trina Morris leads bat research for the DNR’s Nongame Conservation Section.