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Indiana & Northern Long-eared Bat Acoustic Data Analysis

 Second Opinions ✺ Expert Manual Vetting ✺ Complete Acoustic Survey Reports

 Our clients include private developers, state and federal agencies, tribes, private consultants, and educational institutions.

  • False positives with acoustic monitoring are REAL and can significantly needlessly delay your development.
  • If your consultant reports that you have Florida Bonneted bats in your project area, and does -not- have 25+ years of experience interpreting bat calls, it is recommended you get a second opinion on those recordings regardless if you have submitted a report to an agency.
  • If your firm is relatively new to acoustic monitoring for bats, become a partner with BCM and confirm your T&E species results.
Acoustic surveys for bats are challenging. Today’s bat detectors have become so efficient, it is easy to accumulate tens of thousands of files in a relatively short time. But, there is a steep learning curve just to get up-to-speed on data organization, post-processing, call ID, and reporting.

For many species, confident classification can only be achieved on a subset of call types within a bat’s repertoire. The only way to obtain high levels of confidence on species identification is to obtain expert, human review of the recordings.


Indiana & Northern Long-ear Bat Acoustic Data Services

Second Opinion

Bat call analysis software simply points the researcher in a direction of likely identification. Certain software in regular use by consultants is no longer being developed. Threatened & Endangered species ID should also be checked by a bat acoustic expert with many years experience recording and interpreting bat calls signals. False positives occur with virtually -every single- Indiana & Northern Long-ear bat project. This results in costly project delays at the least, at worst there is mis-directed mitigation costing hundreds of thousands of dollars. We provide an important second opinion service on individual call identifications, extremely helpful in confirming or rejecting endangered species presence in your project area critical for informed management decisions. Send us a few of your T&E files for confirmation; price is $295 up to 1 hour with 1 hour minimum on all projects, then $125/hour thereafter.

Data Analysis with Manual Review - for USFWS Compliance Projects 

Site Level Results Backed by Manual Review

USF&WS-recommended surveys require initial results from an automated-classifier, where all recordings are evaluated to obtain Maximum Likelihood Estimates (MLE’s) for presence. We will run your data using the two leading software in North America, SonoBat and Kaleidoscope Pro, providing file-level results from both software on a single spreadsheet. We will also provide a file-level summary of species ID based on auto-classifiers. We will evaluate your MLE outputs and determine site-level, or project-level occupancy based on these values. Most consultants do little more than this automated software run and acknowledge that both false positives and false negatives will remain.

We feel false positives are poor practice and too often lead to mis-directed and therefore wasted mitigation which rarely benefits the target species. Therefore we take extra steps to properly interpret acoustic data. Representative files of each species in each site folder (which may contain weeks of data) are manually reviewed to confirm presence at that site. All files with any software hint as Indiana, Northern Long-ear, or any bat not normally found in the project area bat are manually reviewed. We go 4 ID levels deep to ensure there is no possibility the review will be called into question later; most researchers only look at top level classifications.

Deliverables include the master spreadsheet with any manual review comments. For Indiana bat or Northern longear USFWS requested analysis, the KaPRO output is included, and the master spreadsheet will feature SonoBat, KaPRO, and manual review results side-by-side. This solidly establishes species presence with the least amount of cost regardless of the number of files in the total project. Analysis meets or exceeds current USFWS guidance.


Complete Acoustic Survey Reports

We summarize results of two software analysis outputs and manual-vetting of species of interest either by site level, per site per night, or simply project-wide. In addition to the acoustic data, data sheets and photographs can be included. Uptime is calculated from log files. This service is attractive to those renting detectors or are consumed with field work and are looking for a turnkey analysis and report service.


Files We Accept and Transfer Methods

  1. Full-spectrum (FS) Recordings only (*.WAV format).
  2. Data must be organized in separate folders by detector (site).
  3. We suggest file transfer services such as (up to 30 GB per transfer with account) or, or your own company system if desired. Alternately you can copy files to an external flash/hard drive and mail.
  4. We do not recommend zero-cross (frequency division) recordings (.zc format); expect cost and processing time increase. 


Pricing and Turn-around Time on Recordings:

Project Size

2nd Opinions


Complete Reports

Unlimited files

$295 flat fee up to one hour

$125 each additional hour



Per Site/Per Batch

Unlimited files


$750 for first site

$300 each additional site


In addition to Analysis/Review fee

Turn-around Time

2-5 business days

1 week

please inquire

All Pricing and Turn-around Time estimates are based on materials meeting the acceptance and information criteria above. Expedited service may be available at an additional 50% up-charge fee during certain times of the year.


To submit files or discuss your project, contact
John Chenger
Tel/Text: 814.442.4246

Click here to pay online for analysis services rendered.


Why Bat Acoustic Call ID is Deceptively Difficult

Analysis protocols relying upon auto-classifiers alone are deeply flawed when it comes to determining species presence. There is no computer-program sophisticated enough to take into account all the problems inherent in relying upon automated quantitative analysis of "images" (e.g., spectrographs and spectrograms of echolocation calls). This is because there will always be certain qualitative analysis steps required to address the ambiguities in echolocation call recordings created by:

  1. Artifacts present in echolocation recordings caused by atypical bat behavior (e.g., the affects active foraging and socializing has on the metrics available in sound files vs. those found typical commuting, search phase bat calls)
  2. Atmospheric affects that change how high-frequency sound behaves in air, thus how faithfully it is recorded for confident analysis (e.g., the affects of micro-climate, temperature, wind, and humidity)
  3. The uncontrollable range, approach angle, speed, and direction with which the bat approaches a stationary microphone --and-- the intensity and/or frequency with which the bat echolocates, and other noise in the environment which competes with the bat's ultrasound, any of which can affect signal quality and therefore classification accuracy
  4. The presence of conspecifics and/or allospecifics in the same recording and the affect that multiple bats have on auto-classification accuracy.
  5. Variations in recording hardware, microphones, and recording settings will have significant impact on the number of recordings in a collection that can be classified to species. Liberal settings simply generate a massive data burden of recordings that will never be classified to species, and low end microphones -do not- faithfully record full spectrum sound. 

Considering all of the above, automated classification software is simply a tool to guide the researcher towards the most likely recordings of a particular species. Your data submitted to BCM is reviewed by a bat biologist with years of invaluable experience deploying multiple makes and models of detectors at sites across the country, actively monitoring/recording bats in the wild observing behavior during recordings, and recording voucher calls from individuals where species was confirmed.