3. Bat Detector Comparisons Q1: Are All Detectors Equal? Q2: If Not, What Are Their Operational Ranges?

3. Bat Detector Comparisons Q1: Are all detectors equal? Q2: If not, what are their operational ranges?

Pettersson Wildlife Acoustics D1000X Echo Meter

Song Meter w/ ? SMX-US mic = = 3. Bat Detector Comparisons Field Assessment

Wild = Yard = uncontrolled controlled bats calibration tone 3. Bat Detector Comparisons Field Assessment

Pet EM SM Sampling Rate 384 384 384 (kHz) Max. Freq. 192 192 192 Spectrum (Broadband / BB BB BB Heterodyne) Trigger (dB) 6 6 6

Microphone Uni Uni Omni 3. Bat Detector Comparisons Field Assessment

Pet EM SM Sampling Rate 384 384 384 (kHz) Max. Freq. 192 192 192 Spectrum (Broadband / BB BB BB Heterodyne) Trigger (dB) 6 6 6

Microphone Uni Uni Omni SPECIFICATIONS: MODE 1 Heterodyne Tunable range: (heterodyne) 17kHz – 125 kHz Bandwidth: >16kHz Tape out (3.5 mm socket): line level to right channel only Headphone out (3.5 mm socket): to both channels (8 -16 ohm) Display: 12.5 mm digital LCD with back-light Counter accuracy: less than 100Hz Display Accuracy: 1 digit MODE 2 Frequency division Divide by 10 2. Bat Detectors Dynamic101 input waveform tracking circuit Tape out: line level to left channel only Microphone: electret condenser Field AssessmentRange : 17kHz –125kHz Ref : Momentary voice commentary button to left channel (Ultrasound detection)GENERAL Suitable recording formats: MP3, DAT, MiniDisc, compact cassette Speaker: weatherproof 35mm Ampliﬁer: 350mW (max) Power supply: 1 x 9v PP3 Quiescent current: 22mA Wrist strap: high-strength polyester woven cord Case: ﬁtted soft nylon micro-weave with zip and belt loop Dimensions: 125 x 69 x 32 (mm) Weight: 147gm (without battery)

Due to continuing improvements, speciﬁcations may change without notice. (Windows is a trademark of the Microsoft Corporation) Leaﬂet design : www.mikeharwood.co.uk

Batbox Duet is made in England by Batbox Ltd

Batbox Ltd 2A Chanctonfold s Horsham Road s Steyning West Sussex s BN44 3AA

Tel: 01903 816298

Batbox • LTD www.batbox.com • email: [email protected] 3. Bat Detector Comparisons Field Assessment (Ultrasound detection)

Pet EM SM Sampling Rate 384 384 384 (kHz) Max. Freq. 192 192 192 Spectrum (Broadband / BB BB BB Heterodyne) Trigger (dB) 6 6 6

Microphone Uni Uni Omni 3. Bat Detector Comparisons (callViewer dB comparisons @ 5 & 10 m)

• Wildlife Acoustics Song Meter w/ omni- directional SMX-US mics (1, 2, 4, 6, 7, A, B)

• Wildlife Acoustics Echo Meter (EM)

• Pettersson D1000X (Pet)

1 2 4 6 7 A B EM Pet 3. Bat Detector Comparisons (callViewer dB comparisons @ 5 & 10 m)

OMNI vs UNI 5m 10m 1 57.3 46.2 2 60.2 51.7 4 58.8 48.6 6 32.9 24.6 7 56.2 46.7 A 39.7 29.6 B 58.4 47.8 EM-uni 26.1 20.0 Pettersson-uni 53.7 45.1

1 2 4 6 7 A B EM Pet 3. Bat Detector Comparisons (callViewer dB comparisons @ 5 & 10 m)

OMNI vs UNI 5m 10m 1 57.3 46.2 2 60.2 51.7 4 58.8 48.6 6 32.9 24.6 7 56.2 46.7 A 39.7 29.6 B 58.4 47.8 EM-uni 26.1 20.0 Pettersson-uni 53.7 45.1

1 2 4 6 7 A B EM Pet 3. Bat Detector Comparisons (callViewer dB comparisons @ 5,10, 15, & 20 m) Pteronotus parnellii

5 m 10 m 15 m 20 m

Insect EXAMPLES3. Bat OF Detector BAT DETECTOR COMPARISONS Comparisons

996 A. M. Adams et al. Wildlife Acoustics vs Avisoft @ 5 m increased. The eﬀect of angle was the sameMicrophone among all detectors Quality Comparison: (P > 0 05). There was no interaction between angle and dis- Pteronotus parnellii Á Parnell’s Mustached Bat @ distance ~ 5 m at Windsor, Trelawny tance for 25 kHz signals (P > 0 05), but there was an interac- Á tion for 55 kHz signals (F = 12 62, P < 0 001). For 2,346 Á Á Wildlife55 kHz signals, Acoustics there was SM2BAT-384kHz no diﬀerence between logger 0° and 45°, Avisoft UltraSound CM16/CMPA uni- (USDbut these 850) two angleswith hadSMX-US a greater omni-directional, rate of decline in number of directional, Condensor microphone (USD Electretsignals over microphone distance than 90 (USD°. 150) 4,000 with UltraSoundGate interface (USD 2,000) [+ laptop required] RECORDING FREE-FLYING BATS

Batlogger recorded signiﬁcantly more hoary bat echolocation

Fig. 3. Performance varied among detectors with a strong effect of frequency. Call detection (arcsine square root transformed number of calls) ± SE by call frequency evaluated at a distance of 22 5m.Detec- Fig. 4. Mean number of calls + SE per pass Á tors with the same letter superscriptwerenotsignificantlydifferent relative to Avisoft for each bat detector from from each other within each frequency. recordings of free-flying Lasiurus cinereus on

There was a significant interaction between detector and dis- three nights. Batlogger detected more calls tance for both 25 and 55 kHz signals (F = 9 42, P < 0 001; than any of the other systems (detectors with 4,348 Á Á F4,346 = 13 63, P < 0 001; Fig. 1). For 25 kHz, Batcorder and the same letter superscript were not Á Á Song Meter detections reflectedagreaterrateofattenuation significantly different from each other). with distance than AnaBat, Avisoft and Batlogger. For 55 kHz, AnaBat had the greatest rate of attenuation with distance and Batlogger had the lowest (Fig. 1). Fig. 4. Mean number of calls ± SE per pass relative to Avisoft for each 4 bat detector from recordings of free-flying Lasiurus cinereus on three Overall, there was an effect of angle for both 25 and 55 kHz nights. Batlogger detected more calls than any of the other systems signals (F2,348 = 24 92, P < 0 001; F2,346 = 21 06, P < 0 001; (detectors with the same letter superscript were not significantly differ- Á Á Á Á Fig. 1); the number of signals detected declined as the angle ent from each other).

© 2012 The Authors. Methods in Ecology and Evolution © 2012 British Ecological Society, Methods in Ecology and Evolution, 3, 992–998 EXAMPLES3. Bat OF Detector BAT DETECTOR COMPARISONS Comparisons Avisoft clearly makes higher-quality recordings. 996 A. M. Adams et al. Does this matter since we can still identify the increased.species The e ffofect ofbat angle and was the note sameMicrophone among “flew all detectors past Quality microphone” Comparison: (P > 0 05). There was no interaction between angle and dis- Pteronotus parnellii Á Parnell’s Mustached Bat @ distance ~ 5 m at Windsor, Trelawny tancefor for an 25 kHzactivity signals (P index?> 0 05), but there was an interac- Á tion for 55 kHz signals (F = 12 62, P < 0 001). For 2,346 Á Á Wildlife55 kHz signals, Acoustics there was SM2BAT-384kHz no difference between logger 0° and 45°, Avisoft UltraSound CM16/CMPA uni- (USDbut these 850) two angleswith hadSMX-US a greater omni-directional, rate of decline in number of directional, Condensor microphone (USD Electretsignals over microphone distance than 90 (USD°. 150) 4,000 with UltraSoundGate interface (USD 2,000) [+ laptop required] RECORDING FREE-FLYING BATS

Batlogger recorded signiﬁcantly more hoary bat echolocation

increased. The eﬀect of angle was the same among all detectors (P > 0 05). There was no interaction between angle and dis- Á tance for 25 kHz signals (P > 0 05), but there was an interac- Á tion for 55 kHz signals (F = 12 62, P < 0 001). For 2,346 Á Á 55 kHz signals, there was no diﬀerence between 0° and 45°, but these two angles had a greater rate of decline in number of signals over distance than 90°.

RECORDING FREE-FLYING BATS

Batlogger recorded signiﬁcantly more hoary bat echolocation

calls (relative to Avisoft) than any other system (F3, = 45 26, P < 0 001; Fig. 4), while AnaBat, Batcorder and 100 Á Á Song Meter did not differ significantly from each other. Only AnaBat and Batcorder failed to detect all 26 passes; both of these systems did not record any calls from two passes. One of 3. Bat Detector Comparisonsthe 26 passes included a feeding buzz that was recorded by all of the detectors. Avisoft, Batcorder, Batlogger and Song Meter Fig. 2. Distance of 50% probability of detection calculated with a recorded more calls (23–25 calls) in the feeding buzz than logistic regression for each frequency at 0° by each bat detector system AnaBat (11 calls). Examplesduring from the synthetic playback other experiment. Patterns werestudies similar for all detectors at 45° and 90°,butwithloweroverallprobabilityof detection. Discussion Our results demonstrate that there is significant variation in detectionBatlogger efficacy among (Elekon commercially available AG) bat detectors. The differences in the detection abilities of these microphones, Methods in Ecology and Evolution 2012, 3,992–998 doi: 10.1111/j.2041-210X.2012.00244.x particularlyAvisoft in relation to differing frequency sensitivity, illus- Do you hear what I hear? Implications of detector trate the hazards of comparing data collected by different detectingBatcorder systems. Our results (ecoObs) show that detection of different selection for acoustic monitoring of bats frequencies varied among detector systems and was affected by theSongMeter distance and angle of the(Wildlife signal from the detector. Ac.) Avisoft Amanda M. Adams*, Meredith K. Jantzen, Rachel M. Hamilton and Melville Brockett Fenton and Batlogger detected more of the highest frequency signals Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada weAnabat tested than the (Titley) other detectors, but as expected, these signals were detected at much shorterranges.Detectiondistance In a field comparison of Hoary Bats (Lasiurus cinereus) in Canada, wild Summary bats flew past test microphones 26 times, with a minimum of seven 1. The probability of detecting the echolocation calls of bats is affected by the strength of the signal as well as the consecutivedirectionality calls and frequency per pass. response of Avisoft, the acoustic detectors. Batlogger, Regardless ofand the research Songmeter question, it is impor- all recordedtant tothe quantify full variation number in recording of systempasses; performan ceAnaBat and its impacts and on bat Batcorder detection results. The failed purpose to of this study was to compare the detection of echolocation calls among five commonly used bat detectors: Ana- detect twoBat SD2 of (Titley the Scientific), 26 passes. AvisoftUltraSoundGate116CM16/CMPA(Av Avisoft detected moreisoft Bioacoustics), calls than Batcorder any 2 0 of Á (ecoObs), Batlogger (Elekon AG) and Song Meter SM2BAT (Wildlife Acoustics). the other2. We detectors: used playback of synthetic using calls Avisoft to optimize detectiondata settingsas the for each baseline, system. We then Batcorder, played synthetic Songmeter,signals at fourand frequencies AnaBat (25, 55, detected85 andFig. 115 3.kHz)Performance atfewer 5-m intervals than varied (5–40 among50% m) and detectors three of anglesthe with (0calls°,45 a strong°,90 °in)from e fftheect of fre- the detectors. Finally, we recorded free-flyingquency. bats (CallLasiurus detection cinereus), (arcsine comparing square the number root of transformed calls detectednumber by of passeseach which detector. Avisoft detected.calls) ± SE by call frequency evaluated at a distance of 22 5m.Detec- Á 3. Detection was most affected by thetors frequency with dominating the same the letter signal superscrip and the distancetwerenotsignificantlydi from the source. The fferent effect of angle was less apparent. In thefrom synthetic each signal otherexperiment, within each Avisoft frequency. and Batlogger outperformed other detectors, while Batcorder and Song Meter performed similarly. Batlogger performed better than the other detectors at angles off-centre (45° and 90°). AnaBat detected the fewest signals and none at 85 kHz or 115 kHz. Avi- soft detected the most signals.Fig. In4. the Mean free-flyingThere number bat was experiment, a significantof calls Batlogger + interaction SE recorded per pass 93% between of relative calls detector relative to to Avisoft and dis- Avisoft, while AnaBat, Batcorder and Song Meter recorded 40–50% of the calls detected by Avisoft. for each battance detector for both from 25 and recordings 55 kHz signals of free-flying (F4,348 = 9 42, LasiurusP < 0 001; 4. Numerous factors contribute to variation in data sets from acoustic monitoring; our results demonstrateÁ that Á cinereus onF three= 13 nights.63, P < Batlogger0 001; Fig. 1).detected For 25 more kHz, Batcorder calls than and choice of detector plays a role in this variation.4,346 DifferencesÁ among detectorsÁ make it difficult to compare data sets obtained with different systems.any of Therefore, theSong other the choice Meter systems of detector detections (detectors should reflecte be taken withdagreaterrateofattenuation into account the same in designing letter studies and considering bat activitysuperscript levels amongwith were studies distance not using significantly diff thanerent detectors. AnaBat, different Avisoft from and each Batlogger. other). For Key-words: acoustic detector selection,55 kHz, bat activity, AnaBat bats, had echolocation, the greatest passive rate of acoustic attenuation monitor- with dis- ing, synthetic signals tance and Batlogger had the lowest (Fig. 1). Fig. 4. Mean number of calls ± SE per pass relative to Avisoft for each bat detector from recordings of free-flying Lasiurus cinereus on three Overall, there was an effect of angle for both 25 and 55 kHz nights. Batlogger detected more calls than any of the other systems signals (F2,348 = 24 92, P < 0 001; F2,346 = 21 06, P < 0 001; (detectors with the same letter superscript were not significantly differ- Á Á Á Á have used data from bat detectors to address questions about ent from each other). Introduction Fig. 1); the number of signals detected declined as the angle the echolocation behaviour of bats, as well as their patterns of Echolocation provides a window through which the© behaviour2012 The Authors.activity and Methods habitat in use Ecology (e.g. Gillam and 2007; Evolution Collins© &2012 Jones British Ecological Society, Methods in Ecology and Evolution, 3, 992–998 and ecology of bats can be evaluated. Specifically, calls used by 2009; Mu¨ ller et al. 2012). echolocating bats can be conspicuous to bat detectors, permit- Acoustic sampling is a common, powerful technique for ting biologists to distinguish among species by their calls and monitoring the activity of echolocating bats. Bat detectors are to identify foraging activity. Bat detectors, instruments sensi- widely used by researchers, including those working for gov- tive to the acoustic frequencies dominating bat calls, have been ernment agencies, environmental consulting firms and aca- extensively used in a range of bat studies, from those investigat- demics. Behavioural, presence/absence and relative abundance ing echolocation behaviour, to others documenting patterns of data are commonly collected with these devices. The results of distribution and activity levels. By 2012, the variety of com- research relying on bat detectors inform our understanding of mercially available bat detectorsoffered a spectrum of features bat ecology and behaviour and are frequently used to guide at a range of prices (e.g. weatherproofing, temperature sensors important wildlife management decisions (US Fish & Wildlife and storage options; Table 1) but key features, such as micro- 2011). Acoustic monitoring is non-intrusive and capable of phone quality, sampling rate andrecordingtechnologywill recording large quantities of data. However, the specific com- determine the ability to detect bats. Many published articles bination of hardware may affect the quality, precision and quantity of data collected. Variation in microphone sensitivity and detection algo- *Correspondence author. E-mail: [email protected] rithms can produce data sets that differ among detectors. Both

•Good morning! Anabat (Titley) D500X (Pettersson) SongMeter (Wildlife Ac.) ActivityRatesandCallQuality AR125/FR125 (B.A.T) byDifferentBatDetectors

DonaldSolick,JeffGruver,ChrisNations WesternEcoSystems Technology(WEST),Inc. Which bat detector is best?

Anabat D500x SM2 B.A.T. Activityrate n/a Questionable Comparable Questionable Callquality n/a Good Questionable Good Detection 35m Not tested 45m45m distance Data/power Low High High High burden Weatherproof No Mostly Yes No Remote Yes No No Yes download Cost,single $2,100 $2,100 $1,100 $1,800 Cost,paired $4,600 $4,900 $1,500 $4,000 Susan Koenig attests to the fact that Wildlife Acoustics’ Song Meters are weatherproof . . . and even “riverproof”!

This detector was stolen and dumped into the Martha Brae. Found 6 months later, ﬁlled with river-sludge, the night’s data were retrieved from the SD card, we cleaned it up with de-ionized water, and it worked for another 3 months before ﬁnally giving up the ghost!