On Seeing Sound

- By Gururaja KV, Ph.D., August 3, 2018

I am Gururaja KV, a Batrachologist and a faculty member at the Srishti Institute of Art, Design, and Technology in Bengaluru, India. Also, I am an adjunct scientist at the Gubbi Labs in India. My current research interests are in the field of anuran systematics, behavioural ecology, landscape ecology, and bioacoustics. I am a strong proponent of citizen science and started the Frog Watch program in India. I have completed a week-long workshop on sound analysis at the Cornell Lab of Ornithology in Ithaca, New York. Here are my reflections about the week on seeing sound.

Amplected pair of Kumbara night frog (Nyctibatrachus kumbara)

A new species of Nyctibatrachus was added in December 2017 to the family of night frogs, which stands at 36 species as of today. I was introduced for the first time to Nyctibatrachus almost 20 years ago during my master’s program and I did a dissertation on feeding behavior of a Nyctibatrachus species. Since then, along with my team members, I have discovered two new species – Nyctibatrachus karnatakaensis and N. kumbara. I also discovered a novel breeding behavior and parental care in N. kumbara, wherein an amplected pair does a handstand during oviposition and male individuals do mud plastering of eggs. So every time I hear about the discovery of a new species in the genus Nyctibatrachus, my mind thinks about habitat, calling pattern, breeding behavior, and evolution of these species in streams and forests of the Western Ghats. Simultaneously, I am concerned with making and analyzing recordings of advertisement (breeding) calls, as it is highly challenging to record these calls in the presence of a noisy background due to stream noise.

Thankfully, a fortnight before the news of this discovery I had received an email from Russ Charif that I am one of the two scholarship awardees selected for the Sound Analysis Workshop to be held in the spring of 2018 at the Cornell Lab of Ornithology, Ithaca, New York. The icing on the cake was that my home institute, Srishti Institute of Art Design and Technology, where I currently work as a faculty, supported my travel. I was very excited to learn the sound analysis techniques from the leading researchers in the field and and eager to apply them to my questions regarding Nyctibatrachus genus as mentioned earlier.

With clear instructions from Liz Rowland and Russ about the workshop schedule, I ensured that my arrival would be at least a day or two earlier to the workshop as jet lag is inevitable for a person traveling from a country that is 9.5h ahead of Ithaca. My tickets were booked for 29th March departure from Bengaluru to Delhi to New York. From New York, I took a Campus2Campus bus service and by 4:45 pm on 30th March, I was in Cornell University North Campus.

The Fallen Tree – my free accommodation in Ithaca
Birdwatching at Sapsucker Woods sanctuary

On 1st April, along with another workshop participant, a researcher from Ecuador, I stepped out for birdwatching in the Sapsucker Woods sanctuary at around 7am. From my temporary residence, it was less than a 15-minute walk to reach the sanctuary area and another 10-minute walk to reach the Cornell Lab of Ornithology building. Having had a bright sunny day and temperate blue sky on the previous day, I thought the weather would be similar. However, it turned out to be a breezy and cold day. After finishing the birdwatching walk at around 8:30am, my face felt dry and I got the taste of the chilly Ithaca wind for the first time.

Johnson Museum of Art at Cornell University

In the afternoon, I visited Herbert F. Johnson Museum of Art on Cornell University campus. From the fifth floor of the museum, I had a glimpse of Cornell University, downtown Ithaca, and Cayuga Lake. At around 6:30pm all the participants and instructors of the Sound Analysis workshop had gathered at a local restaurant for a pre-workshop dinner and introduction. It was wonderful to see people from eight different countries with equally varied topics coming together to learn the sound analysis.

Day 1: With a brief introduction of all the participants, Russ started off the workshop by providing a detailed outline of the week. This was a great start to the workshop as it set the tone for what to expect in the next 5 days. Luciana Andrade gave a presentation on bioacoustics of Guiana dolphins (Sotalia guianensis) in Rio de Janeiro. We had a short session on what our expectations were and where our learning would go from here. We learnt about acoustic measurement options, including robust measurements, that are available in Raven Pro. At the end of the day, we had a good understanding of sound and digital audio. Through the learning of the day, I had a better understanding of instrument settings when I record frog calls.

Pre-workshop dinner with the SAW team
Orientation about the Imogene Powers Johnson Center for Birds and Biodiversity, home of the Cornell Lab of Ornithology
Introduction to acoustic analysis by Russ Charif
A behind-the-scenes tour of Macaulay Library

The following are my takeaways from this workshop

This Sound Analysis Workshop (SAW) is unique among those that I have attended, as it blends both theoretical underpinning and hands-­on analysis.

Technical sessions were interspersed with relevant talks from other researchers, which had a direct impact on our understanding about sound analysis as well as on approaches to our research.

The training has helped me a lot in understanding sound theoretically as well as how to carry out sound analysis. I am now more confident of using Raven Pro 1.5 and its features. Earlier, I used sound analysis only for taxonomic identification of species, but now I am better placed to use it for comparative analysis, diversity, and density analysis.

Day 2: Instructions started with how to customize Raven Pro for more efficient usage, which helped me understand Raven Pro’s capabilities better. Later in the day, the lectures covered discussions about issues related to audio recording artifacts, clipping, and aliasing issues, in audio recording. Sound to Noise Ratios and anti-aliasing were also discussed. As a part of the participants’ presentations, I gave a brief presentation about my research work and how I was planning how to use the knowledge of this workshop in my research. Russ gave a detailed lecture about spectrogram parameters and introduced us to an automated detection tool, Band Limited Energy Detector (BLED), available in Raven Pro. I had never attended such an intensive session learning about sound analysis. By the end of the day, I was working on the frog calls that I recorded from the Western Ghats in India and I was using BLED to detect various species in that recording.

Day 3: We started the day having a birdwatching session with Chris Pelkie at Sapsucker Woods. Chris showed birds, shared his experience as well as gave insights on the history of Cornell Lab of Ornithology. I was impressed by Andy Goldsworthy’s “Sapsucker Cairn” installation within the sanctuary. Later in the day, we attended a lecture on selection, review, and annotation tool available in Raven Pro. This particular exercise helped me work efficiently on long records with many frog calls. Karen Odom presented song structures in Fairy Wrens. Russ discussed about quantification of sound similarities and spectrogram cross-correlation. Marcelo A. Salas, a postdoctoral fellow at the Lab, introduced us to warbleR and Rraven, which are customized acoustic analysis tools in the R software platform. We had a brief visit to Macaulay Library where we learned about the history of the library and the sound archival process.

Day 4: We revisited spectrogram cross-correlation analysis. We had a demonstration from Marcelo on warbleR and Rraven. Daniela Hedwig from the Elephant Listening Project gave a talk on elephant acoustics. I had one-on-one discussion with several instructors about my planned research program in the Western Ghats of India. They shared their experience and helped me in shaping my project better. There were presentations by other workshop participants that were very inspiring.

Sense of accomplishment - a certificate from the Cornell Lab of Ornithology
An early morning birdwatching hike sets the mood for a day of learning
Smile at the end of a short but productive week at the Lab

Day 5: Following a visit to the Cornell Museum of Vertebrates, we had a behind-the-scenes tour of Bioacoustic Research Program. At BRP we learned about some of their new projects including SWIFT and BirdNET. At this point, I had the sinking realization that this wonderful hands-on workshop has come to an end.

Impressed as well as inspired by the SAW, I have proposed to conduct a Bioacoustics recording and analysis workshop in the forthcoming Students Conference on Conservation Sciences in Bengaluru, India. I am asking many of my research students and colleagues to attend this workshop in future.

My sincere thanks to Russ, Ashik, Bobbi, and Liz for the wonderful workshop.