| The Anabat system, then and now. Special edition blog post provided by Margaret Clarke. |
Post published on: June 30, 2022
Static ultrasonic bat detectors that can be left to record for weeks at a time in the field are taken for granted nowadays, but such equipment was not available to most bat workers until the introduction of the Anabat zero crossing detector in 2003.
THEN:
I first recorded barbastelle bats (barbastella barbastellus) in 2000 when we discovered them in woodlands in West Wales, but soon became frustrated that we could only record a few hours at a time, a time of frequency division output on to minidisks. I longed to be able to leave a detector to record remotely for a week or more so that we could learn more about the barbastelles. Then at the end of 2003 I saw the Anabat system advertised and lost no time in acquiring two of the zero crossing detectors, which consisted of a frequency division detector and a zero crossing interface module (ZCAIM). Zero crossing files were recorded on to flash memory cards allowing the detector to be left in the field for many nights.
In 2004 the detector, ZCAIM module and lead-acid battery were cumbersome and difficult to mount on a tree, but this home-made arrangement with thin plastic film protection for the microphone, worked well.
The Analook analysis software was an essential part of the Anabat system. The methods and concepts introduced by Chris Corben, the short files which could be species labelled, filters and automatic measurement f call parameters, the extraction of metadata, including GPS data for mapping were new then but have since become widely adopted by bat workers and form the basis of most analysis software today. The Anabat system allowed me to carry out surveys and monitoring on barbastelles which would otherwise have required a number of observers to spend large amounts of time in the field.
In 2005, Chris Corben developed the Anapocket program that could be installed on a PDA (personal digital assistant) with a display screen. Connected to the Anabat detector and with a Bluetooth GPS receiver it provided a hand-held detector with which one could record geotagged files and view real time Anabat displays. Watching bat calls in real time helps relate the calls to bat behaviour and quite transformed the experience of active bat monitoring for me.
NOW:
Fast forward to the present day and we can see how the early versions of the Anabat system have evolved with developments in technology. The ZCAIM recorder was replaced first by the SD1 and SD2 models and now by the Anabat Express, a robust weatherproof zero crossing detector, loved for its compact data files and comprehensive analysis tools by consultants who need many detectors out in the field.
But with the enormous increase in the capacity of memory cards, Titley has been able to introduce a full spectrum detector, the Swift. Like the Express, the Anabat Swift is compact, weatherproof and easy to use, it has built-in GPS and temperature data logging and provides everything needed for round the year static surveys. I have recently been using Swift detectors to study the distribution of barbastelles in an area in the east of England.
AnalookW has now been incorporated into the analysis program Insight which has a new user interface and can be used to analyse both zero crossing and full spectrum recordings.
And finally, the hand-held zero crossing detector and PDA system has been replaced by the Walkabout full spectrum detector which includes almost anything you could want in a hand-held detector. The full spectrum display is excellent and the detector is a pleasure to use.
I find that I am using the same basic methods and analysis techniques that I used with the early Anabat systems but newer semiconductor technology has made all elements of the system easier to use. I am grateful for Chris Corben for his development of the transformative Anabat system which has given me the tools for many years of exploration of local bat populations and for the study of barbastelles.
