The unit records night sounds, particularly bats. These recordings are then fed through a computer program, Kaleidoscope Pro, which analyzes call sequences. As DNR writes, “This is used to determine the most likely bat that would produce each call sequence. This means that we may not be able to determine the exact species of bat that produced every call and that there may be some errors in the results.”
The Anabat unit can determine things like activity periods throughout the night, as well as species diversity to some degree, but it is not able to determine species abundance.
Let’s say the machine records a certain species. It cannot accurately report how many of that species live here at the farm. One bat could be flying around the unit all night long, squeaking its head off.
The data is submitted to the North American Bat Monitoring Program (NABat) run by the U.S. Geological Survey. The purpose of this program is “to monitor bats at local to range-wide scales that will provide reliable data to promote effective conservation and long-term viability of bat populations across the continent. “
Georgia DNR is participating in this program state-wide on both public and private lands.
June 11, 2018 -- June 14, 2018
Calls identified to species: 100
At least one bat of the following species were identified with a 95% or more “confidence interval” (determined by the overall number of calls collected at the site):
- evening bat (Nycticeius humeralis)
- tri-colored bat (Perimyotis subflavus) – This is a Georgia species of concern currently under consideration for listing as an Endangered Species, so we’re particularly happy about this one.
- Brazilian free-tailed bat (Tadarida brasiliensis)
- northern yellow bat (Lasiurus intermedius)*
Other sound files not identified as bats: 2,774
The biologists thought these were most likely insect calls. The guineas make weird noises at night, and there are lots of owls. Mockingbirds are sometimes night-birds. As I write this it’s night and I’m hearing crickets, frogs of many species, and some deep eerie whale-like ringing that is probably the universe singing to itself.
*Trina Morris, wildlife biologist with Nongame, wrote to us that “This detection of a northern yellow bat so far away from the coast is unusual. We have historic records of this species in the upper coastal plain but haven’t captured any in this area recently. It is certainly possible that this species could be found on your property, but we cannot consider it a true record until it is verified by a hand capture.”
That could be exciting.
(PHOTO CREDIT: Tri-Colored Bat, Al Hicks, NYSDEC, nynhp.org, with thanks)
June 3, 2019-June 6, 2019
Calls identified to species: 129
- eastern red/Seminole bat (Lasiurus borealis, Lasiurus seminolus) – Apparently these two species can’t be differentiated by their calls, only by sight. Because of its geographical distribution it’s expected to be a Seminole.
- northern yellow bat (Lasiurus intermedius)
- tri-colored bat (Perimyotis subflavus)
- hoary bat (Lasiurus cinereus)
Other sound files not identified as bats: 1,967
That is six species of bats recorded here. Some were here one year but not the next. All this is so strange and wonderful.
This year the unit comes down on Juneteenth.