Click a question below to see the answer to many common queries about the results of the Big Bat Counts.
If we haven’t answered your question fully, please do email us: somersetbatgroup@gmail.com
Q. How accurate is the automated species ID on the tablet?
For some species it is very accurate. The Echometer software usually gets Soprano Pipistrelle, Common Pipistrelle and both Horseshoe bats right.
For some bats species it is “best guess”, for instance it can’t reliably tell the 5 Myotis species apart at all: Daubenton’s, Natterer’s, Whiskered, Brandt’s and Bechstein’s.
The EchoMeter does also give some false positives to sounds like Crickets or Landrovers, particularly to these species: Noctule, Lesser Noctule (Leisler’s) and Western Barbastelle.
Lastly couple of really rare species, can only be IDed in the hand or from DNA. As they impossible to tell apart from commoner species from their echolocation alone, we have disabled the AutoID for grey-long-eared and Alcathoe bats on our tablets.
Q. What equipment did we use on the Big Bat Count?
For automatically IDing the bats we use a Echo Meter Touch 2, this is plugged into a basic 8″ Samsung tablet, however many phones and tablets are compatible.
For listening to the bats we use a Heterodyne detector the Magenta 5.
Full details of these, cost and suppliers, are in the Which Bat Detector page of our website. The page also incudes details of lots of other bat detectors, including cheaper options.
Q. Why is one of our observations miles away from where we were?
There are two possibilities, either:
- EITHER, the phone/tablet had an incomplete GPS location.
- OR, this is deliberate by iNaturalist to protect rare species. When a species in iNaturalist is listed as “near threatened”, then the location online is randomised within a 10km square
Q. Why can’t I see the results map online?
The different versions of the iNaturalist App, and the website have different capabilities. Try opening the links in a web browser (not App.) preferably on a laptop or computer.
Q. Why do number of “on the night” (unverified) observations, and those verified records produced from the recordings later, differ?
This is usual, and there are several factors at play:
- The recordings are checked to see if the tablet correctly IDed the bat.
- There are also usually some clear bat recordings that the tablet didn’t identify.
- We don’t upload duplicates. Each species record uploaded is a minimum of 20 meters apart.
- We only select the best, clearest recordings, and don’t upload any faint or noisy ones.
- To prevent confusion in validation we try to pick recordings that only have one species.
Q. What’s the difference between our observations “on the night”, and those “verifiable”, and verified “research grade” records uploaded later?
On the night you are entering into iNaturalist that you have observed a species of bat. However as there is no evidence to prove this, the observation is unverifiable, and is termed “casual” on iNaturalist.
The recordings stored on the tablet undergo automated and manual verification after the night, and the “best” are added to iNaturalist using a bulk upload tool. On this new iNat record are a couple of pictures (spectrograms) showing the bats call as it appeared on the tablet screen, along with an upload of the original recording. This evidence will allow other bat experts to check the bat species. In this way this record is “Verifiable”.
If two thirds of bat experts agree with the species we suggested, then this record becomes a “research grade” or verified. These are the records that can be uploaded to Environmental Records Centres databases at a latter date.
Q. Why are the statistics I see on iNaturalist now, different to those mentioned on the bat group website?
We publish the stats about the verified recordings at the time we upload them to iNaturalist. The stats on iNaturalist may change over time, as other bat experts agree, or disagree, with our identifications.
Disagreement between experts is most commonly about the 5 (6) Myotis species, as these have VERY similar echolocation to each other