You'll go Batty over this Detector!

A Review and Quick Start Guide to the Echo Meter Touch 2 Bat Detector:

I love to record all wildlife, whether in my garden or on my local patch; I like to know what’s about! One group of animals that always tend to remain a mystery as to which species are present are bats. Just because of what they are and the time that they are about, makes them hard to identify without specialist equipment. They come out during the hours of darkness (mainly) and whiz past before you get a chance to check them out, which often isn’t even possible! So, for much of my natural history recording life bats have remained a mystery; or at best I have made a good guess at the small ones in my garden being Common Pipistrelles, and the large ones on my local patch being Noctules. But that is all they were, guesses.

Many years ago I bought the most basic bat detector on the market. One that required you to dial in the frequency of the bats that you expected to see, and then if you were correct you’d hear the call through the speaker on the device, converted to a frequency audible to human ears of course. This only worked if you had some idea what was present and the scale was so crude that it would miss some species that had call frequencies of a similar value.

Recently I discovered that there was a bat detector available that could revolutionise my species recording, but my initial thoughts were that a price tag of £199 seemed quite steep and I all but dismissed it as too expensive. After doing a bit more research into bat detectors I realised that for a device that had similar capabilities, I would be paying a four-figure sum of money. Chatting to pals working in Environmental Consultancies it wasn’t unusual for them to spend around £2,500 on such a device. Suddenly £199 was looking cheap!

The device in question is the Wildlife Acoustics Echo Meter Touch 2 Ultrasonic Module and is designed to plug into either an iPhone or an Android Phone depending upon which model you purchase. This compact little piece of kit plugs into the charging port of the phone and works via an App that is free to download for your bat recording. The beauty of this detector is that it identifies the bats that you are watching based on the frequency of their calls without the need to ‘dial in’ to any specific frequency. This feature is otherwise only available on devices priced in four-figures, as previously mentioned, and so makes bat detecting available at a reasonable price to hobbyists and amateur recorders as well as to professionals who have a limited budget.

My mind was made up, so I purchased a unit and downloaded the App and then was itching to try it out, firstly on the bats in my back garden. Before use a few settings needed to be selected on the App. The simplest of these was the region, selecting Europe and then the UK narrowed the ‘possibles’ list of species down to those that have been recorded in the UK only. Most of the other settings could be left at the default values, but one that I looked at carefully was the sensitivity of the ID criteria. This could be set at 3 levels, the first level was one that was very strict and would only record a species as present if it was certain. The next level could be described as the ‘average’ level which worked on the high probability that a species was present given the number of call ‘pulses’ recorded from that bat. Finally the lowest level required many fewer positive ‘pulses’ for a species to be suggested as the one being recorded. I started off by using the average setting, but experimented once I started to use the detector, more about that later!

My first opportunity to use the Echo Meter Touch 2 came that evening in my back garden. I have watched bats feeding over the garden for the last 20 or so years, and had always assumed that the species present were Common Pipistrelles. So, out I went just after dusk and as usual small bats were sweeping through the garden arcing back and forth and just perfect for my first recording session. Switching the unit on via the App it immediately sprang into life with high pitched chirps emanating from the phone and a visual representation of these sounds appearing on the screen. With the detector in record mode I captured several passes of the bats and then switched off to head inside to see what I had found. I switched over to ‘Recordings’ and selected the first one. There was my ID, and I was really surprised to see that it was a Soprano Pipistrelle, not the species that I had expected, but one that I would have had difficulty positively identifying on my old detector. Opening up the remaining 5 recordings confirmed the ID, all recordings relating to Soprano Pipistrelle. A great first try, but not the end of my nightly sessions!

For the next few weeks a trip into the back garden each evening with the Echo Meter Touch 2 was essential, with different times tried including just after dusk and even just after midnight. This perseverance was rewarded with additions to the garden bat list. The first new addition was two weeks later when Common Pipistrelle was seen flying with the Soprano Pipistrelles and identified by the App. Then Noctule was added a week later, but the bat was up very high and not feeding low over the garden like the pipistrelle species. Finally, a month and a half after starting, Brown Long-eared Bat was recorded, possibly an unexpected species but events just a fortnight earlier had alerted me to the presence of this species locally. I was called out to a neighbour’s house where a cat had brought a bat inside. To my amazement the species that had been caught was Brown Long-eared Bat. This individual was rehydrated using a syringe, fed and rested up overnight before being taken to a local animal rescue centre for full rehabilitation. My recording sessions were curtailed when the weather was poor, but in the third week of September on a fine night, my fifth garden bat species was recorded in the shape of Leisler’s Bat, or Lesser Noctule as it is also known. The number of ‘pulses’ assigned to this species out of the total number of ‘pulses’ in the recording in question make me think that it is highly likely that the ID in this instance was correct; but more about the accuracy of IDs later.

As well as the garden bats, I ventured further afield and spent a night on my local patch, Newchurch Common, just 3 miles away from my home but with significantly different habitats including woodlands, dense scrub and lakes & ponds. The single night’s recording here logged Soprano Pipistrelle as the commonest species, as in my garden, with Common Pipistrelle not far behind. Noctules were recorded more frequently that at home and again a Leisler’s Bat recording was highly probable given that 100% of the ‘pulses’ recorded were assigned to this species. I was surprised not to log Daubenton’s Bat due to the presence of water bodies here, but future planned visits to recheck this were scuppered by weather and other commitments. Again the accuracy of sightings here will be discussed below.

To make a recording I would point my device towards a likely bat area or even at a visually seen bat and then switch to ‘Live Mode’ to activate the detector. Immediately I always pressed the smaller of the two red buttons on screen, the left-hand one, which triggers recording mode. After a period of my choice I would touch the larger red button - the right-hand - one to stop recording. If left on for a long period the device would stop and restart recording to produce several files from a single mini-session. Once the recordings are made with the Echo Meter Touch they are on the App on your phone until you decide to delete them. You access these in the Settings Menu under ‘Recordings’. Once you open up recordings you are able to choose each one individually. The recordings show a bat symbol, which if lit up yellow means an ID has been made. The six letter bat code for the most likely ID is also shown, this is the first three letters of each half of the binomial (or latin) name of the bat. For example Soprano Pipistrelle has the latin name Pipistrellus pygmaeus and so the code is PIPPYG. By selecting a particular recording the data is displayed as a Spectrogram trace above and a frequency bar at the bottom. In the middle the yellow bat symbol can me touched to show ID with less likely alternatives also listed if relevant. Information about the bat species can be seen by clicking the ‘i’ information symbol next to the bat picture.

The recording can be played back using RTE or HET settings, or to slow it down a TE (Time Expansion) setting is available. A full online manual is present in the Settings Menu for a more complete explanation. The main aims for the user are to be able to switch on, record and look at ID when using this detector, and these are really easy to do. Each night’s session is colour coded to help if looking back for a particular date. One important setting in the Settings Menu is the Auto-ID Sensitivity. This has three levels, Sensitive, Balanced and Accurate. These names are not immediately obvious as to which level is best for the best ID, but in summary Sensitive is the lowest accuracy with IDs being suggested at lower thresholds, and in my experience this setting gives some inaccurate IDs and suggests species that are highly unlikely when looking at species distribution in the UK and official bat records for given counties. The top level, Accurate, has the most severe criteria with only absolutely nailed on IDs being shown. This may mean that a fleeting call may not be deemed enough to suggest an ID and, in this way, some ‘sightings’ may be missed. My preference is for the middle level – Balanced – which looks at recordings and gives the highest probability of ID given the number of ‘pulses’ for a particular species within the overall recording and will also suggest other less likely possibilities too. In this mode I recorded Leisler’s Bat when only 2 ‘pulses’ were captured, but 100% of these related to Leisler’s as an ID. If a bat flashes by when you are in a position with less than ideal ‘viewing’ of the area being surveyed, a few pulses may be all that you can capture, so I prefer this mode. One really nice feature though, is that after the recordings are made you can switch between the three sensitivity settings and the App will reanalyse the recording and re-evaluate for that degree of sensitivity. This can confirm an ID suggested at Balanced by switching to Accurate and seeing if the ID is still there; or just for fun switching to Sensitive can throw up possible IDs from recordings previously coming up as ‘No ID’. I say just for fun, because doing this has thrown up some unlikely IDs such as Barbastelle Bat at Newchurch Common and Alcathoe Bat in my garden. Neither species has been officially confirmed in Cheshire, so discovering two new species for the county in my first couple of months detecting is highly unlikely! By switching back to Balanced mode these two recordings return to a ‘No ID’ result which is what I will record too. The lowest Sensitive mode has also suggested Serotine at Newchurch Common which, although not impossible, is unlikely, so again I would rather believe the ‘No ID’ given in the Balanced mode for that same recording.

Whether you use this for fun or to monitor the bats in any given area, I would highly recommend the Echo Meter Touch 2 Bat Detector as it makes bat recording really easy and, at what I now recognise as a really low price of £199, it is an affordable option for amateur wildlife watchers.