Qualitative Identification of Free-Flying Bats Using the Anabat Detector

O’Farrell, Michael J.; Miller, Bruce W.; Gannon, William L.

doi:10.2307/1383203

Cited by 175 publications

(77 citation statements)

References 16 publications

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“…As was found last year, the California myotis had little to no tail extension and a recorded minimum frequency around 50 kilohertz, while the small-footed myotis had a 1-2 mm tail extension and a minimum frequency around 40khz. This is consistent with the findings of Constantine (1998), O'Farrell (1997), andO'Farrell et al (1999).…”

Section: Bat Species Of Concernsupporting

confidence: 92%

Ecological Monitoring and Compliance Program Fiscal Year 1999 Report

Wills¹

1999

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Section: Bat Species Of Concernsupporting

confidence: 92%

Ecological Monitoring and Compliance Program Fiscal Year 1999 Report

Wills¹

1999

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“…memory card and later analysed by the ANALOOK programme (Chris Corben, version 0.3.8.13, http://www.hoarybat.com). The ANABAT system is widely used for bat surveys worldwide and has the advantage of being able to record huge volumes of bat call data automatically and efficiently (O'Farrell et al 1999;Milne et al 2004;Monadjem et al 2010;Williams-Guillen & Perfecto 2011;Skalak et al 2012). In some cases, detectors were deployed continuously from sunset to sunrise whereas in other cases, recording was carried out only for the maximum foraging period of bats, approximately two hours after sunset (Table 1).…”

Section: Methodsmentioning

confidence: 99%

Diversity of Bats in the Soutpansberg and Blouberg Mountains of Northern South Africa: Complementarity of Acoustic and Non-Acoustic Survey Methods

Taylor

Sowler

Schoeman

et al. 2013

South African Journal of Wildlife Research

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We surveyed bats at 30 localities in the Soutpansberg and Blouberg Mountains within the newly proclaimed Vhembe Biosphere Reserve (VBR) of northern South Africa, based on ANABAT acoustic recordings (63 nights) conducted in parallel with captures of 260 individuals from harp traps (29 trap-nights) and mist nets (54 trap-nights), and searches of ten day-roosts and two night-roosts. Twenty-four species of bats were captured, or positively identified from roosts, out of 44 species previously recorded for the VBR. For those species captured during the study and one additional commonly recorded species, Chaerephon ansorgei, which was not captured, we compiled a library of ANABAT call parameters for reference calls, based on released bats or bats emerging from known-species roosts. Reference calls were obtained from the study area where possible, or from the closest possible site in the savanna region of southeastern Africa. Using principal component analysis and plots of frequency histograms of selected parameters, we investigated the extent to which reference calls of different species could be distinguished on call parameters. Complete separation was obtained for most species but certain species-pairs or trios showed overlap, particularly amongst molossid bats. Accurate identification of unknown calls was complicated by natural intraspecific variation in echolocation call structure due to habitat and behaviour in our species-rich study area. We advocate a conservative approach whereby species-pairs or groups with overlapping calls are treated as single 'species'. Such underestimation can be partly corrected using rarefaction approaches, as illustrated by data collected from Blouberg Nature Reserve. Particularly when surveying bats in species-rich areas such as the eastern savannas of southern Africa, both acoustic and capture-based surveys are necessary to accurately estimate true species richness. From our capture data and roost searches, we recorded nine to 14 species at four west-east, grouped localities defined by this study. Adding acoustic data using a conservative approach to classify overlapping species-pairs or trios, we obtained minimum richness estimates of 15 to 21 species, values which were close to those predicted by a recent macro-ecological model. We found no evidence for a west-east increase in richness with increasing precipitation as predicted by coarse-scale macroecological predictions.

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“…Each has its eligibility in different situations . The use of combined methods in a self-contained apparatus becomes more and more widespread and the risk of oversimplistically applying them is rising and controversially discussed (Barclay 1999;O'Farrell et al 1999aO'Farrell et al , 1999b. The influence and experience of the observer will always be a dominant factor in such inventories, unless automated systems classify with decision trees (Herr et al 1997) or artificial Variability in echolocation call design of 26 Swiss bat species neural networks (Stocker 1998) on the basis of automated measurements.…”

Section: Data Reductionmentioning

confidence: 99%

“…2). The latter is achievable in real time with a limited amount of hardware (e.g., ANABAT system, Titley Electronics 1998;O'Farrell et al 1999a), while spectrogram calculation usually necessitates a fast computer. However, period-or zero-crossing plots do perform badly with weak or noisy signals, blurring the display considerably (Fig.…”

Section: Introductionmentioning

confidence: 99%

Variability in echolocation call design of 26 Swiss bat species: consequences, limits and options for automated field identification with a synergetic pattern recognition approach

Obrist

Boesch

Flückiger

2004

Mamm

173

122

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Pattern recognition algorithms offer a promising approach to recognizing bat species by their echolocation calls. Automated systems like synergetic classifiers may contribute significantly to operator-independent species identification in the field. However, it necessitates the assembling of an appropriate database of reference calls, a task far from trivial. We present data on species specific flexibility in call parameters of all Swiss bat species (except

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Qualitative Identification of Free-Flying Bats Using the Anabat Detector

Cited by 175 publications

References 16 publications

Ecological Monitoring and Compliance Program Fiscal Year 1999 Report

Ecological Monitoring and Compliance Program Fiscal Year 1999 Report

Diversity of Bats in the Soutpansberg and Blouberg Mountains of Northern South Africa: Complementarity of Acoustic and Non-Acoustic Survey Methods

Variability in echolocation call design of 26 Swiss bat species: consequences, limits and options for automated field identification with a synergetic pattern recognition approach

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