The future of bat detectors

Don’t get too excited, it’s only a mock up

The basic rule of technology is everyhting gets smaller, more capable and cheaper, though so far the application of that rule to bat detectors seems stalled at the £1000 mark for anything of serious use.

I’ve been using Ultramics for two years now to capture realtime full spectrum recordings at Myotis swarming sites. Up until now that’s required a netbook to run the software, not massively cumbersome but combine it with infrared video kit and a trek across moorland and you certainly feel the weight.

So it was good to hear from Ivano at Dodotronic that they’re working on an android compatible version of the Ultramic; the Ultradroid. A small ultrasound microphone combined with the computing power of a 7″ tablet? The potential to record, geolocate and identify bat calls in realtime all with a full colour easily visible display?

I’ve already bought a Google Nexus7 tablet, I’m ready.

 

Wildlife Acoustics EM3 – First thoughts.

Wildlife Acoustics EM3 – First thoughts.

EM3 with gps

EM3 with gps

So I’ve had the EM3 for a  couple of survey nights now and had the chance to use it both for static and transect surveys. To start with I’ve used the detector with settings straight out of the box as it’s marketed as being “shipped ready for use” with “settings (which) allow you to begin monitoring bats in minutes”.

Firstky it has to be said that rumours of a flimsy detector seem to be unfounded, it’s not something I’d want to drop onto a hard surface but the EM3 feels sturdy and up to it’s intended use. It fits comfortably in the hand and is light enough not to notice holding it even after a couple of hours use. The self contained nature and lack of faffing with cables is a bonus in this respect.

Plugging in the gps it took about five minutes to obtain a  fix and start displaying lat/long in the status bar of the display which seems reasonable for first use. There isn’t enough leaf canopy coverage to test it’s abilities in woodland at the moment so that’s something for a later test.

Microphone sensitivity seems fine, I’ll be testing it alongside both the D240x and Anabat to get some comparative data, and the default trigger point for recording seems to be a reasonable balance between picking up bats but filtering out car passes and other environmental noise. You will hear fainter bat calls in your headphones that don’t trigger the record setting but it’s down to individual preference or survey aims to decide on where that trigger point should be.

My transect headed out alongside a busy road with several popular Pip feeding spots before dropping into the valley to return alongside a river, pond and sewage farm, usually a guaranteed spot for five species although it’s still quite early in the season so I wasn’t expecting great results. Along the road the detector ignored most passing vehicles but still triggered to record when bats were encountered. All good so far, and the lack of noise files is something that should speed up processing later.

Heading down to the river and away from street lighting I switched the display to white (sonogram) on black (background) from the default black on white to try and keep some night vision but it became noticeably more difficult to pick out the sonogram on the display. This is something I’m going to try to solve next time I’m out by tweaking brightness levels in both settings and seeing which works best. I was happy to leave it because I don’t think there’s much value in trying to identify bats off the small display, I’d rather do that back at home with the recordings on a laptop screen. For me the detector screen seems more suited to monitoring recording state and confirming activity levels.

Back home and it’s time to download the data, which is an easy job of removing the easily accessible SD card and copying files over onto the laptop hard drive. For me the main selling point of the EM3 is it’s ability to record in wav/zca setting which captures both a realtime full spectrum recording and a zero crossing data file. This should allow a quick workflow by use of AnalookW to process the easy species and switching to full spectrum for the Myotis where more songram measurements are useful.

I was a bit surprised to find that although I had 355 full spectrum wav recordings, the detector had only processed 40 zca files. This potentially has a knock on effect for anyone using Batsound for analysis as the time to process 355 calls is considerably longer than 355 data files in AnalookW. It wasn’t partial passes or quiet bats that were missed out on either several busy spots with multiple bat passes had no corresponding zca file. It looks like some tweaking of the zca threshold setting may be needed from default.  I’ll also be comparing recording in wac (Wildlife Acoustics proporietary uncompressed audio) mode then converting the resulting file to zca to see if that gets better results.

Summary?

So far I’ve been really impressed by both the ergonomics and the potential of the EM3. The promise of monitoring straight out of the box is a hard one to live up to but I reckon with a bit of tweaking default settings to get rid of the niggles the detector should be a very useful survey tool.

Next step is to play with settings then a full review review will be published here

Wildlife Acoustics EM3

Wildlife Acoustics EM3 Active Ultrasonic Bat Detector

From: http://www.wildlifeacoustics.com/

Price: £979.99 plus £199 for GPS

Pro’s: Compact system, full spectrum and zca recording, simplicity.

Cons: ZCA file production needs tweaking, gps noise interference

EM3

EM3 packed with everything you need to start recording (gps optional extra)

The Wildlife Acoustics EM3 is a full spectrum bat detector / recorder with the capability to georeference recordings via an optional plug in gps unit. One of the bonuses from a workflow point of view is the ability to record in wav/zca setting which produces both a realtime full spectrum recording and a zero crossing data file suitable for analysis in AnalookW. This in theory allows you to process zca files to identify easier species such as Pipistrelles but have the use of full spectrum calls for more in depth analysis of harder to identify species.

EM3 first look

EM3 up close

First impressions are here.

I’ve been using the EM3 for a full survey season now and have to agree with Dave Dodd’s that whilst it’s the detector I reach for automatically for most work it is also capable of slowly irritating me over the span of a night.

Ergonomically I’m happy with the package of EM3 and gps puck, it’s easier to hold and lighter in the field than an Anabat, gps and pda. I’m still working on eliminating the inevitable sound files created as you shift it in your grip, something a silicone sleeve might resolve. The detector is a perfect set up for transects and with the option of a seperate wired input for an additional microphone should work perfectly for car use too. Although capable of static programmed surveys I think I’d rather leave that to the SM2Bat+ which is designed for the job.

Recording wise the detector took a fair bit of tweaking in threshold settings before I was happy with the production of zca files, this isn’t such a great issue now that Wildlife Acoustics have now released Kaleidoscope a very handy utility for converting wav files to zca that seems to produce very reliable results. Recordings are crisp and clear and the live black and white sonogram display is great for in the field ID of easier species.

The main advantage over the Anabat SD1 and pda is the lack of connections and potential for issues arising from them. Previously with the Anabat SD1 there were weak points between anabat-pda, pda-bluetooth gps that had the potential to decide out of the blue to not talk to each other; a frustrating scenario when you’re out on site and in the dark. I often carried a separate gps and serial lead “just in case”. With only the gps puck to plug in to the EM3 that’s all disappeared, I no longer have that worry at the back of my mind.

I’ve found I tend to monitor calls in the EM3′s RTE mode, effectively a realtime time expansion and keep the four option buttons programmed to flick between 20,45,55, and 110khz hetrodyne modes. A nice and simple system to flick between even in dark conditions.

All good so far. So that annoyance?

It’s a frustrating one; without the gps plugged in headphone sound is superb but once the gps connects it’s a different matter with a low level variable shussing feedback that inevitably becomes a distraction. This seems to happen regardless of whether you’re listening in hetrodyne or rte mode and is the only downside to what could be a very capable detector. Hopefully it’s something that can be cured with a frimware update, support is one thing Wildlife Acoustics have certainly got dialled with user forums and firmware updates.

*Update: After speaking to Sherwood from Wildlife Acoustics at the BCT National Conference it appears the gps noise issue is to do with hardware so unable to be solved by software. It’s a niggle we’re going to have to live with.

 

 

Dodotronic UltraMic200k digital USB microphone

 

Dodotronic UltraMic200k digital USB microphone

From: http://www.dodotronic.com/index.php?center=11&left=1

Pro’s: Real time, full spectrum recording. Futureproof.

Cons: Needs netbook and software so not suitable for transects. Not suitable for all UK species

Dodotronic UltraMic200k

Dodotronic UltraMic200k

Although not strictly speaking a bat detector, combine the Dodotronic UltraMic200k with a netbook and you’ve got a  light and portable mechanism for capturing full spectrum echolocation in realtime (which is where bat detectors are heading) and all for circa £500.

Ultramic200k and Netbook

Ultramic200k and Netbook

With a sample rate of 200k you’ll only record sound up to 100khz with the UltraMic200k so for some species you’re better off spending the extra on the UltraMic250k which captures sound to 125khz. Sound can be captured using BatSound, SeaWave or other software.

Sure it’s more suited to static surveys (I’ve been testing this one at swarming sites), and identification during data sifting is going to take longer; to say nothing of data storage issues associated with large files.

But, and this is a big but, I believe we’re on the cusp of the next stage in bat identification with automatic identification software just over the horizon. Couple one of these mics with a smartphone or tablet running the right software and you’ve got a powerful, affordable and accurate method of surveying and identifying bats in flight.

Link to the User Manual

Expect to see a Ultramic250k review soon.