Mobile Transect Reveal Slight MYAU Range Extension in Florida
BatSS has been conducting a weeklong Acoustic Survey Methods in Punta Gorda, FL for several years now. Mobile transects in the pine flat woods and prairies has always shown mediocre activity. So lately few we have been incorporating night kayak transects because of the lack of trails and roads along FL rivers. Just one of our river trips yield orders of magnitude more activity and species than all other previous road transects combined! We hit the jackpot this year with some suspicious myotis-type calls recorded along the Peace River; we have never recorded the Southeastern myotis MYOAUS during our South FL workshops before, and we are ~60 miles south of the limit on range maps.
Always skeptical of acoustic recordings, we sent .wav files to AnaBat Chris Corben: "Beauty! Definitely Myotis and completely consistent with MYAUS." And SonoBat Joe Szewczak weighed in: "Ding Ding Ding!"
So, we aren't going to argue and considering MYAU -is- a big river-loving bat, we'll going to just have to live with our little myotis friends a little further south in FL than previously thought!
These were just 4 files from 1 detector, there are likely a few more recordings on other detectors from our armada of monitoring boats. SonoBat made it easy to test the files for MYAU... we just loaded them all in the SonoVet tool and flipped to a classifier that considers MYAU such as north FL, and voila, our 800+ recordings were instantly re-classified and the MYAU stuck out!
Above: Overview of one night and one microphone's transect data (Binary Acoustic Technology MiniMic and SonoBatLIVE). I hid FRAGHI, FRAGLO, TWOBAT, and PESU to declutter the screen. The PESU when turned on cover the entire map, obscuring everything else. Note the lack of TABR on this section of the Peace River. Note the MYAU and EUFL recordings that become apparent. All data was manually reviewed in SonoBat, then this map generated using Transect & Google Earth.
Above: A view of a second transects few nights later showing a second MYAU location. Note the TABR scattered around this transect whereas they are absent from the upstream survey just ~10 miles away for whatever reason. This transect is closer to I75 which may have TABR roosts in bridges.
If using solo kayaks, run a passive microphone as high as you dare. The rocking of the boat as you paddle will really whip it around. Point WAC and BAT mics straight up. Leave cones on D500x. If its a tandem or larger boat, then you have room for someone to watch an Echometer or SonoBatLIVE, but you still need to cable the mic preferably 10' or more above the water to reduce echos. Turn OFF the species auto ID on the Echometer Touch, it is notoriously wrong and often mis-IDs noise as bats.
Choose a class A-C type river, unless you have a lot of experience. Take spotlights. Run it once in the daytime so you know about where the downed trees and shallows are.
We put the detector in a dry bag and roll it up with the cable. Using SBLIVE is a little trickier... the surface pro gets hot if you shove it in a tight dry bag. We only used one of those and the person in the backseat of the tandem holds it or can secure it to the back of the front seat. So it never went in a dry bag. The person in the front has to be watching for trees/rocks/shallows, not the SonoBatLIVE.
Some of us also carried BatScanner Stereos with earbuds just for fun and to make sure there should be bats recorded. it's amazing how many bats you hear but cannot see even with whipping the spotlight around.
- John Chenger