For her PhD analysis, bat biologist Kadambari Deshpande made in a single day recordings of bat echolocation calls within the Western Ghats. A “good night” would generate about 30 GB of information from 11 hours of recording with a bat detector. To course of the information, Deshpande would undergo a number of one-minute recordings, scanning each millisecond for bat calls, and make notes on the species and different info on their behaviour and ecology.
“It took me 11 months to process 20 nights of data,” Deshpande mentioned. “BatEchoMon can probably give me that in a few hours.”
BatEchoMon, quick for “Bat Echolocation Monitoring”, is an autonomous system able to detecting and analysing bat calls in real-time. It is India’s first automated bat monitoring system, developed by Deshpande and Vedant Barje below the steerage of Jagdish Krishnaswamy, as a part of the Long-Term Urban Ecological Observatory within the School of Environment and Sustainability on the Indian Institute for Human Settlements (IIHS), Bengaluru.
Deshpande is a postdoctoral fellow on the Observatory and the School; Barje, who leads the WildTech Project on the Wildlife Conservation Trust, is a guide there.
BatEchoMon marks a brand new chapter for bat analysis within the nation, in keeping with Deshpande. The monitoring system permits chiropterologists — scientists who examine bats — to “go beyond data processing and towards asking interesting questions about bat ecology”.
“Not only will it lead to a smoother workflow, it will help people transition to recording bats in different parts of the country, allowing us to gain more insights on the natural history and ecology of different bat species,” Rohit Chakravarty, a bat researcher and conservationist on the Nature Conservation Foundation, mentioned.
“I don’t know of any device internationally with an in-built recording plus call classifying unit. If my knowledge serves me well, BatEchoMon is a milestone in bat research globally.”
The bat within the machine
BatEchoMon is greater than a bat detector. Aside from a recording gadget, it contains elements that may file, retailer, course of, and analyse species-wise bat exercise on the fly. Bat detectors are solely the specialised recording units that may convert the ultrasonic echolocation calls of insectivorous bats into audible sounds for people. “In [BatEchoMon], Audiomoth, a popular low-cost ultrasonic detector, has been configured to work as an ultrasonic microphone,” Barje mentioned.
BatEchoMon is programmed to activate mechanically at sundown, when bats start flying, and constantly listens and analyses audio. The gadget’s mind is a Raspberry Pi microprocessor, which processes the information captured by Audiomoth. “It first isolates bat calls from other ultrasounds, such as those of insects or anthropogenic and environmental noises. Then the peak frequency and structure of a bat call are analysed to match a known pre-trained model, which helps identify the bat species,” Deshpande defined.
“The system uses a [convolutional neural network] based algorithm to do this,” Barje added. The output from the gadget is a spectrogram — a visible illustration of the frequencies of an audio sign because it varies with time — of all detected bat calls, together with audio recordings of the parts with simply the calls. The system additionally generates statistical information on which species has been most lively by means of the evening, which species was lively when, and so forth.
“Earlier, all of this needed to be interpreted manually, after painstakingly combing through hours of data,” Deshpande mentioned.
The Raspberry Pi and its related processing elements are enclosed in a field measuring 200 mm × 80 mm × 80 mm. Other auxiliary elements within the gadget embody a photo voltaic panel plus battery and a WiFi communication unit for energy provide and information transmission, respectively. In the absence of the solar, the gadget can final for as much as eight days, in keeping with Barje.
BatEchoMon additionally has a modular design, and its battery, charging equipment, and the extent of automation and information relay will be customised to the house it’s put in in. But the workforce was reluctant to disclose extra in regards to the setup course of at the moment.
‘Suddenly, it became possible’
Bat ecology and acoustics is a nascent area in India, with only a handful of bat researchers recording bat calls and analysing them for ecological research. Global bat-call databases akin to ChiroVox and Xeno-Canto have few recordings submitted by Indians.
Deshpande has been utilizing bat detectors since 2008 and has noticed their evolution worldwide. In Europe, she mentioned, detectors geared up with the related software program and reference libraries have saved scientists a variety of time. Since then she has needed to develop one thing related, however customised for the insectivorous bats which might be extra widespread in India.
An opportunity assembly with a fellow researcher and engineer from her hometown in Nashik, Maharashtra, kickstarted the BatEchoMon challenge. “Meeting [Barje] just revolutionised the whole thought. Suddenly, it became possible,” Deshpande mentioned.
The duo went by means of quite a few iterations, making an attempt totally different microprocessors, algorithms, and energy options — a “big challenge”, in keeping with Barje — earlier than arriving on the present model of BatEchoMon. Their major objective was to incorporate all the specified performance in a user-friendly, low-cost bundle.
The core system of BatEchoMon prices one-third of superior detectors and related programs, in keeping with Barje. He didn’t want to disclose actual numbers, nonetheless.
The predominant problem
In the previous few months, BatEchoMon has efficiently accomplished pilot checks in an IIHS web site in Nashik. The workforce plans to check it for longer durations and in various circumstances in addition to to beta take a look at the gadget with choose customers exterior the organisation.
“Everybody comes with their own experiences of acoustics and different species. So eventually, we would like our colleagues to test it for themselves and share their experiences so that we can improve on the existing system,” Deshpande mentioned.
The major impediment for BatEchoMon is the restricted availability of reference libraries for the calls of many bat species. “Currently, the system can identify six to seven common Indian bat species. Going forward, we would like to include as many bat species as possible,” Deshpande mentioned.
They additionally mentioned they hope the gadget in its current type will be capable to determine the species generally seen in city, peri-urban, and human-modified forested areas. The predominant problem is to create sturdy coaching datasets to make good detection fashions for various species — a problem they hope to beat by collaborating with different bat researchers.
Fortunately, collaborations amongst Indian researchers are bettering due to initiatives such because the ‘State of India’s Bats’ workshop carried out by the Nature Conservation Foundation and Bat Conservation International, in keeping with Chakravarty.
“One of the key knowledge gaps identified by participants at the workshop was the lack of a thorough reference call library,” he mentioned. “We also need more funding to conduct surveys in different parts of the country. It will allow researchers to identify more species and gather more recordings for training datasets.”
Nikhil Sreekandan is an unbiased journalist.
Published – April 14, 2025 05:30 am IST
