Ok, that's maybe overdoing it a bit, but I have recently become a fan of the Anabat SD1. For some time now the SD1, and it's more cumbersome predecessor the Anabat II (with ZCAIM recorder) has been the industry standard equipment world-wide for passive monitoring, and rightly too, but having spoken to several people who rated it highly as a detector for use on transect surveys I though I'd better try it out.
There are several reasons the Anabat is so good for passive recording. Alternative methods of recording bat calls use audio formats such as .WAV or .MP3, which quickly gobble up available memory in just a few hours. The Anabat records each bat pass as a series of co-ordinates, plotting the loudest frequency every few milliseconds, creating miniscule data files, allowing many thousands of bat passes to be squeezed onto a single 1Gb CF memory card.
The fact that the memory card is held within the detector is a further advantage, but the biggest advantage lies in the way the detector ignores the spaces between bat passes and simply records each bat pass (or other ultrasonic noise) as a new file. The Analook software which comes with the machine allows you to very quickly scroll from bat call to bat call, identifying each pass and creating a spreasheet showing each one, with date, time and species. The time saving, compared with using other software analysis systems, such as Batsound or Batscan is huge.
So the Anabat is great as a passive detector - why is it good for transect work? The designer, Chris Corben, has built in an interface which allows a GPS receiver to be plugged into the detector. Every two seconds the Anabat asks the GPS where it is and records that data on the CF card, alongside all the bat passes it records as you walk along. This means that for each bat you encounter you have a sonogram of it's call, the date, the time and an accurate grid reference.
There are several reasons the Anabat is so good for passive recording. Alternative methods of recording bat calls use audio formats such as .WAV or .MP3, which quickly gobble up available memory in just a few hours. The Anabat records each bat pass as a series of co-ordinates, plotting the loudest frequency every few milliseconds, creating miniscule data files, allowing many thousands of bat passes to be squeezed onto a single 1Gb CF memory card.
The fact that the memory card is held within the detector is a further advantage, but the biggest advantage lies in the way the detector ignores the spaces between bat passes and simply records each bat pass (or other ultrasonic noise) as a new file. The Analook software which comes with the machine allows you to very quickly scroll from bat call to bat call, identifying each pass and creating a spreasheet showing each one, with date, time and species. The time saving, compared with using other software analysis systems, such as Batsound or Batscan is huge.
So the Anabat is great as a passive detector - why is it good for transect work? The designer, Chris Corben, has built in an interface which allows a GPS receiver to be plugged into the detector. Every two seconds the Anabat asks the GPS where it is and records that data on the CF card, alongside all the bat passes it records as you walk along. This means that for each bat you encounter you have a sonogram of it's call, the date, the time and an accurate grid reference.
Anabat SD1 with Etrex GPS velcroed to it and connected.
What more could you ask for?
Well, I've made it sound great, and it is, but there are plenty of problems too (though apparently Titley Electronics, who make the machine have recognised that there is a huge market for the machine and are working hard at improving it):
1. The GPS data isn't attached to the sonogram: you have to transfer it manually.
2. Even with the GPS and Anabat both set to the correct time, an error of one hour creeps in, though it's easily edited out.
3. Becasue the machine is built in Australia, the GPS data is recorded as Latitude and Longitude, using the WGS84 datum, instead of the British OS datum. This means you have to use a utility programme to convert the data to British National Grid and remember to convert the datum, otherwise you can end up with proper-looking grid references, which are simply wrong.
4. The standard Anabat microphone is not as sensitive as it could be. I set the Anabat's sensitivity control as high as it could take and used it alongside a Bat Box Duet. The Duet was clearly more sensitive, which was disappointing, given the Anabat's £1,400 price tag.
Despite all the above, Anabat plus GPS is still streets ahead of anything else currently available. When used together with the GPSU GPS utility programme and the superlative DMAPW mapping programme, bat data can be identified and transferred to a map with incredible ease and efficiency. Unlike Victor wotsit, the chap who was so impressed with a shaver he bought the company, I didn't go that far, but three weeks after buying an Anabat for passive monitoring I'd bought another for transect surveys, despite the high price.
2. Even with the GPS and Anabat both set to the correct time, an error of one hour creeps in, though it's easily edited out.
3. Becasue the machine is built in Australia, the GPS data is recorded as Latitude and Longitude, using the WGS84 datum, instead of the British OS datum. This means you have to use a utility programme to convert the data to British National Grid and remember to convert the datum, otherwise you can end up with proper-looking grid references, which are simply wrong.
4. The standard Anabat microphone is not as sensitive as it could be. I set the Anabat's sensitivity control as high as it could take and used it alongside a Bat Box Duet. The Duet was clearly more sensitive, which was disappointing, given the Anabat's £1,400 price tag.
Despite all the above, Anabat plus GPS is still streets ahead of anything else currently available. When used together with the GPSU GPS utility programme and the superlative DMAPW mapping programme, bat data can be identified and transferred to a map with incredible ease and efficiency. Unlike Victor wotsit, the chap who was so impressed with a shaver he bought the company, I didn't go that far, but three weeks after buying an Anabat for passive monitoring I'd bought another for transect surveys, despite the high price.
I was on the receiving end of a hard sell for this system at the Welsh Bat Conference and failed to understand why I would want to pay an extra £400+ for this. Titley admit that the PDA screen will cause you to lose your night vision and advise that you should carry it, pointed away from your eyes! The bracket looks utterly Heath Robinson and vulnerable. When I pointed this out I was told that the bit which would break if you tripped whilst carrying it would be the bracket, the cheapest part...at £100!
In fairness to Titley and to Chris Corben, this is an excellent idea and has immense potential. Why plug your bat survey data into a computer when you can take the computer to the bats, but there's a lot of work to be done yet. Meanwhile, like many others, I am waiting with baited breath for the new Batbox Griffin to be launched. It just might beat Anabat at their own game.
Chris Corben's Anabat website: http://www.hoarybat.com/
Batbox, makers of the new Griffin: http://www.batbox.com/
GPS Utility: http://www.gpsu.co.uk/
Alan Morton's DMAP mapping programme: http://www.dmap.co.uk/
And of course, my website: http://www.plecotus.co.uk/
3 comments:
Hi David
I'm also a fan of the Anabat SD1 - I have two. I also use a Pettersson D240x which has better sensitivity/range but as the playback of a 1.7 second sample takes 17 seconds it can only actually record 9% of the time, whereas the Anabat is continuous. It's fiddly also having to control a recording device as well as the detector. Ive had a couple of incidents where the lead wasn't plugged in properly and I lost a whole evenings recordings. The Anabat's simplicity in the field is a huge advantage. The Anabat's passive monitoring capabilities are also very impressive - I haven' used them with an external power source yet but I hope to soon. I also discovered recently that you can get an extension lead for the microphone (20metres I think). This may be useful if it's not possible to leave the whole unit in an area.
cheers
Leyton Williams-Davies (Survey Ecologist, Torfaen County Borough Council, SE Wales)
Re the Anabat SD1, as you will see I am also a fan, however using an PDA is excellent especially with a GPS cf card, just download your data from the PDA's memory and you have all the lat/long readings in your sonogram data, the GPS data can then be converted using software from GPSU and then loaded straight into Google Earth & other programs therefore showing the location where bats were identified, fidly at first but useful. Loosing night vision I disagree! Set the backlight to the lowest, this gives out less light than using a headtorch to write your notes, which points me to the fact I now use a voice recorder for notes and type them up the next day, yes more typing but I now look for bats rather than at a clipboard. Last but not least a bespoke bracket for the PDA = less than £5.00 + cable £4.00 also add a tripod mount useful for passive monitoring, Welsh conference or was it an Anabat conference? Which ever it was, as allways GREAT
David,
Another point, the time being out by 1 hour can be fixed, you probably had the initial setting on GMT try resetting the detector's time with the serial connector.
Roger
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