(Lightly edited for readability)
Speakers: Manjari Jain, Subhra Priyadarshini
00:01 Sponsor announcement: This episode is produced with support from DBT Wellcome Trust India Alliance.
00:26 Subhra Priyadarshini: Have you ever walked near woodlands or rain-fed roads and heard a pleasing and sometimes deafening chorus of birds, frogs, and insect calls? Have you ever thought about what these creatures are communicating? Are they calling for a mate? Sounding an alarm? Or discussing something else altogether?
Listening in to these conversations of birds and insects to make sense of them is what behavioral ecologist Manjari Jain does for a living. She researches the interface of ethology, ecology and evolutionary biology. To be more precise, she studies acoustic communication in animals – decoding their language for us so to speak.
On this episode of the Nature India podcast series called “I am a Scientist and this is where I work”, join me, Subhra Priyadarshini, in understanding the environment’s soundscape. We will travel today with Manjari Jain, an Associate Professor in the Department of Biological Sciences at the Indian Institute of Science Education and Research in Mohali. We will walk through her many places of work – in the open skies, under the soil and in muddy puddles, and inside dense forests.
Manjari, so glad to catch up with you. Will you take us into your workplace, or in your case, all the exotic sounding ‘places’ you work in.
02:00 Manjari Jain: Yes, so I have been very lucky to have worked in a variety of landscapes ranging from tropical deciduous forests, scrub jungles, evergreen forests, and now to urban parks and woodlands. Each landscape brings with it a unique environment, a unique soundscape, we study how animals communicate with each other using sound. What do these sounds tell us? And how much information can the receivers extract from these sounds? So my PhD work was in the dense tropical evergreen forests of Kudremukh, where we would enter the forest only after sunset, and stay on till about midnight, we would record insects and bats. And as you can imagine, the forest at night is full of sounds, not so many sights. And given that we are in the tropics, this is a huge diversity of sound that you are going to be subjected to.
03:11 Subhra Priyadarshini: Jungle sounds – wow! So like most of us with desk jobs, or lab jobs, of course you can’t complain of monotony in your work. You wake up each day to a new experience. It must be so stimulating, but sometimes is it intimidating?
03:28 Manjari Jain: For me the first time when I entered the forest, it was overwhelming the amount of noise that surrounded me, full of the chorus of insects, and it was only after a few months that I learned how to pay attention to individual sounds. Bats, on the other hand, as you know, use high-frequency sound so we can't hear the bats but we could often see the bats moving around. Now, my work is mostly in urban gardens, in woodlands and parks where we study common backyard birds to understand how much information can we extract from the sound with regards to the biodiversity that surrounds us.
04:12 Subhra Priyadarshini: Wow, intriguing! So can you help us decode the sounds of insects and birds, their interactions, and behavior or the problems that they face in their environment?
4:24 Manjari Jain: The insects that I work on are nocturnal insects, that is they're active at nighttime, these are crickets and katydids largely focuses on their behavior, but also on the evolution of their acoustic signals, why are the calls shaped as they are for given species. Another important problem is what is known as The Cocktail Party Problem. So, imagine you are a cricket and you are calling from somewhere in the ground, and you're surrounded by other crickets of your own kind and of different species. The interesting thing that you must know is that only males can produce sound, and the females are silent. But the females exercise choice as to which male they would meet with. So the males advertise using sound, or serenade the females. And the females then respond to it by approaching the males in complete darkness just using the sound alone. But when all of this is happening in an orchestra of sound, it's going to be challenging for the male to pass on information without that information getting lost in sound, which is what we call as acoustic masking interference, where multiple sounds overlap with each other.
05:42 Subhra Priyadarshini: And what about my core area of interest in all of this – the birds?
05:47 Manjari Jain: With the birds of course, and for this I use social babblers as the model system, there are several species of babblers in India. Some of them live in like a joint family if you like in these social groups, which are family units, the jungle babbler that they do produce different kinds of sounds and it is likely that these sounds carry some meaning. So, we decoded the babbling of the babbler. And we now know what each sound means. We have characterized the acoustics of the birds’ vocal repertoire. For instance, if a call is made up of multiple notes – tuck, tuck, tuck, tuck, tuck – you have each note which could be of a unique kind. We ask if these calls are kind of randomly organized or is there ordering of these notes? So, just the way meaningful words that we use in human language they have a certain odor to it right. And of course, we are interested in their social life we want to understand how they coordinate their group activities using sound but also how and what they do all day? And they produce certain kinds of calls when they are foraging, which are known as flight calls. And they start producing these flight calls when an individual starts to exhibit, you know, wanting to move from that location. Also, how they take care of the young ones, parental care, brood parasitism in these birds.
07:14 Subhra Priyadarshini: That is a whole bunch of questions you’re trying to answer. So what kind of preparation do you have to do? Tell us about the gadgets you carry and things you have in your backpack when at work?
7:26 Manjari Jain: Yeah, so, for the insect work, since it is mostly in the night time, and for the bat work, you need to have a torch headlamp so that you can find your way especially when you are in the forest and at that time also lead socks and boots so that you can storm through vegetation without getting bitten by you know, snakes, since we work on sounds, we need a lot of battery backup, equipment lab, two laptops, battery motor battery to power my speakers. For the birds’ work, on the other hand, we need to carry poles for mist netting, mist net bands, colour bands, vials to store certain kinds of samples. So, and a table to prop this up to keep everything in place. So there's a lot, you have to be extremely organized.
8:16 Subhra Priyadarshini: Not just with tools and gears but also preparing mentally to go into these ecosystems for long hours to long days, then waiting for these creatures in the dark dense forests – tell us about the mood, the set-up and then when you listen to these sounds, what’s going on in your mind?
8:36 Manjari Jain: Yeah, so that's a fantastic question because I don't know how to answer this without looking like a really scared little, I don't know kitten. So when I first walked into Kudremukh, my heart sank. Because we are humans are very visual animals. And I just couldn't see anything. You don't even see the stars because there's this massive canopy of trees, right. But your senses with respect to what you can hear, you're overloaded there.
And I could hear crickets and frogs and all kinds of eerie sounds everywhere. And there were calls of civets and lorises, which sound like someone is shrieking inside the forest which all, you know, relate to the very conventional notion of forest being an extremely dangerous place. I would get extremely scared listening to some kinds of sounds.
9:35 Subhra Priyadarshini: That must have taken some getting used to! Birds communicate with vocal sounds or visual cues. On the other hand, frogs and toads have vocal cords. Chirping is how crickets communicate. These messages are used by birds and insects to find mates, keep track of friends & family, locate food, stay safe from predators, and defend territories from rival birds.
So Manjari, it would be really interesting to hear some of the latest research findings from this extensive field work that you do, which of course, needs tonnes of patience and determination.
10:17 Manjari Jain: So the process of science is time-consuming. There are very few moments of finding – it is a long, long-drawn process. I will give you one example from my insect work and one example more recently from the bird work.
So with the insect work, when I entered the forest, it was just so noisy there was a cacophony of sounds. And the first question that came to my mind was, how do they communicate in this noise?
So you can think of like an FM, so bands on the radio, you can tune into certain bands, and then whatever is happening in the other channel is not kind of doesn't interfere with your work, right?
With the crickets, in combination with how their sounds are structured, wherein some sounds fall in the silent intervals of other species. If you look at one thing at a time, it doesn't make sense, it still sounds like a cacophony. But if you put all of these assets together, a holistic view, there is zero, cacophony. So there is silence in this cacophony. And that was something absolutely fantastic, incredible for me. Of course, the animals are communicating, which means that clearly they are being able to overcome the masking problem. We just didn't know how. It was a great moment for me to figure out how they were actually avoiding masking.
We worked on the sounds vocalizations of purple sunbird, another very common backyard bird. The Bird song is made up of phrases and the phrases are made up of notes, which is something true for many songbirds but what we found was there was ordering of these notes, there seems like certain kind of, some kind of underlying rule which determines which note will be present in which position within a phrase. There are certain kinds of linguistic laws which were thought to be followed only in primate species and we have now found evidence for that in jungle babblers as well.
12:15 Subhra Priyadarshini: Ooh, purple sunbirds and jungle babblers' linguistics, that does sound fascinating. Now coming back to the rain forests, what kind of hurdles or unusual challenges do you come across while working there?
12:31 Manjari Jain: Yes, so the work I did in the rain forests was done in Kudremukh National Park. And then there was a lot of conflict between the forest department and locals and a lot of unrest. We would be locked out of the forest because the check posts have just shut down there has been some conflict. People were displaced.
With respect to risk from wild animals, it is not the carnivores, usually, that one needs to worry about, I think it's, you know, large herbivores. So elephants are a problem. And there have been times when we had to just abandon our work and you know, pack up everything and run because there has been an elephant around. So the next day, when I arrived in the morning to check. We find that the one elephant had come and had stomped around entire quadrat crushing our plastics tools. it was really unhappy that we were there and it had, you know, defecate it all over our quadrat so that really kind of, you know, freaked me out a bit. Although I must emphasize that the risk from wild animals, in my opinion, was far less than the risk of getting involved in some kind of conflict between the administration and the locals.
I would say that difficulty was far more serious to me, than the presence of wild animals, which is what most people associate working in forest to be risky for.
13:56 Subhra Priyadarshini: Of course, one can see why you’d consider that risky. In your research spanning almost two decades, trying to understand birds and insects better, do you see any change in yourself as a person?
14:10 Manjari Jain: So initially, it was extremely frustrating every time I would hear the babbler I would just go crazy, I would see that there is distinctive behavior. Obviously, when you walk through the garden. you know, this is the flight call so they're going to move from here, this one is lower left behind it's calling for this group members. So this is instead of, you know, joy and happiness, which cannot be described.
14:33 Subhra Priyadarshini: Back to nature is an in thing these days. This research discipline takes you closer to nature in every possible way. Do you think that might appeal to youngsters who’d like to choose an unusual science stream? What would you tell young researchers?
14:50 Manjari Jain: The first thing I will tell is I have talked about some of the limitations and dangers of working in this kind of field. But these are what I would say occupational hazards and these are there even for the most seemingly safe work environments. So come to this field, only if you are mentally ready for this. The other thing that nobody talks about is the isolation that you will feel in these forests and landscapes where we have most of our field stations. It can really affect you affect your mental health. So be aware of this. It's a marathon and not a sprint.
15:29 Subhra Priyadarshini: Absolutely. Most people would think of their workplace as a place with set working hours, clean toilets and coffee vending machines. That’s a far cry for Manjari, for whom an entire biodiverse ecosystem is her workplace. And about this workplace, she continues to create awareness through public outreach and nature education.
If you liked what you heard on this episode of the Nature India podcast, share it with friends and colleagues, and check out our archives for more in both English and Hindi.
We’ll meet again soon with another fascinating episode of “I am a scientist and this is where I work.”
Thanks for tuning in. I’m your host Subhra Priyadarshini and this is the Nature India podcast.
16:35 Sponsor announcement: This episode was produced with support from DBT Wellcome Trust India Alliance.
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