Listening To Wild Soundscapes

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A new field of biology called 'soundscape ecology' has scientists recording all the sounds in a given habitat and listening for patterns and changes. Ecologist Bryan Pijanowski and bioacoustician Bernie Krause discuss what we can learn from listening to natural soundscapes.


This is SCIENCE FRIDAY. I'm Ira Flatow. Hope you are enjoying our Earth Day, your Earth Day today. And you know, one of the catalysts for the first Earth Day back in 1970 was the very influential book "Silent Spring" by Rachel Carson.

Remember that? Remember the point of the book? By listening to the sounds made by living creatures or the silence of the silent spring, we get a better understanding about the state of the environment.

Well, since then ecologists have turned on their microphones and have been recording all kinds of sounds coming from a landscape. Biologists in the past tended to focus on the sounds of a single species made, but what - the sounds they made.

But now there's a new field of biology, and it's looking at all the sounds of a habitat as sort of like a symphony. And what they are hearing is very revealing about the overall health of a habitat, and we hope to share some of those sounds with you.

My guests have spent decades listening to and recording what they dub soundscapes, all the sounds coming from a given habitat. Bryan Pijanowski is associate professor of forestry and natural resources at Purdue University in West Lafayette, Indiana. His work is published in the journal Bioscience, describing this new field, soundscape ecology. Welcome to SCIENCE FRIDAY, Dr. Pijanowski.

Professor BRYAN PIJANOWSKI (Purdue University): Thanks, Ira.

FLATOW: You're welcome. Bernie Krause is a bio-acoustician and CEO and president of Wild Sanctuary in Glen Ellen, California. He's also the author of the upcoming book "The Great Animal Orchestra: Finding the Origins of Music in the World's Wild Places." He joins us from KCRB(ph) in California. Welcome to SCIENCE FRIDAY.

Mr. BERNIE KRAUSE (Bio-Acoustician): Happy Earth Day, Ira.

FLATOW: Happy Earth Day to you. Bryan, can you tell us what this new field is all about, soundscape?

Prof. PIJANOWSKI: Yeah, I mean, you know, ecologists, like you said, have really focused on recording and trying to understand the biological significance of a single species. And what we're trying to do here is look at all of the sounds in the landscape.

And so we're proposing in this paper to really launch a new field that we call soundscape ecology, which is a branch of spatial ecology called landscape ecology.

So basically what we want to do is look at various sources of sound that is kind of emanating from a landscape, and those sources are biological in nature. We call that biophony. And geological or geophysical, that we call geophony. And of course humans produce sounds as well, and we call that anthrophony.

So what we want to do is understand those sounds and then relate it to ecosystem health.

FLATOW: Bernie Krause, what can you learn about the health of an ecosystem from there?

Mr. KRAUSE: Well, as Bryan said, you know, we're contrasting older expressions like acoustic ecology, and soundscape ecology assumes that the natural soundscape is an ongoing, profoundly informative narrative. It's the world's first theatrical, acoustic manifestation that among other things kind of provides us with instant feedback as to how we're treating the natural world.

Biophony and geophony together make up the voice of the natural world, and Bryan and his team at Perdue, and others at Michigan State, like initiated by Stuart Gage(ph), were among the first to academically recognize the scientific value of using holistic natural soundscapes rather than species-specific recordings.

FLATOW: And with so much to choose from, Bryan, how do you figure out just where and what you're going to record and listen to?

Prof. PIJANOWSKI: Well, you know, in the last couple of years there have been great advances in technology. So we've been able to take digital microphones and put them out in different kinds of habitats and record continuously.

And what we do is we take that information, bring it back to the lab and begin to analyze it and look at different patterns. And some of the things that we summarized in the paper is that the acoustics, the biophony in natural environments, was very rich. But as we moved into more human-dominated landscapes, like agriculture areas and urban areas, we kind of lost kind of a biological signature.

And so we're calling - one of the things that we're trying to do is look at what I call the rhythms of nature. How do these signals change over time? So in the morning, for example, we have a dawn chorus that's very prominent in natural landscapes, and a dusk chorus.

So those are reflective of, we believe, of very, very healthy ecosystems.

FLATOW: (Unintelligible) as we say in radio, a sound is worth a thousand pictures. So it's better if I play - let me play a sample of what you're talking about so our audience can get an idea. And let me give out the number first, 1-800-989-8255 if you'd like to talk about this new soundscape ecology.

Let me play the first cut, and this comes from the Madagascar jungle.

(Soundbite of jungle)

FLATOW: It's beautiful. That could put me to sleep at night, soothing.

Prof. PIJANOWSKI: It absolutely beautiful, and this is one of Bernie's wonderful recordings.

FLATOW: Tell us about it, Bernie. What were we listening to there?

Mr. KRAUSE: Well, actually, it's a recording made by Doug Quinn(ph). But you know, what's happening here - he was a colleague of ours. And what's happening here is - it's as if Darwin himself was defining the sonic timelines of evolution.

These choruses in a healthy habitat, like the one we've just heard, they go kind of like this: First you hear the insects, and they establish their acoustic territory within the frequency spectrum, and then you hear the reptiles and the amphibians. They join the chorus, establishing other niches.

And once those are set, then come the birds and finally the mammals and all of the critters together, creating not only frequency bandwidth but temporal niches as well. It's kind of like the first proto-orchestra.

FLATOW: Do they know they're playing together?

Mr. KRAUSE: You bet they know, because if they don't stay out of each other's way, then their voices are masked. So they have to learn to sing in relationship to one another, just like instruments in an orchestra.

Prof. PIJANOWSKI: You know, what I think is very interesting here is - you know, I'm an ecologist, and you know, one of the things that Bernie has been using is all these metaphors related to music, composition, orchestration.

And, you know, I struggled for a long time, as I began to listen to many of these recordings, mine and Bernie's and Stuart Gage's. And I really had to kind of go back to music to be able to begin to describe what I was listening to.

So as a scientist, I thought that was kind of interesting that I really had to use maybe another field to help me understand what it was I was listening to in my ecosystem.

FLATOW: Interesting. Let me go on and play a couple of more cuts that sort of demonstrate how you can tell when things are happy in the critter world and when things are not working out so well.

And let me go to one about that we have a coral reef. You can actually record underwater? We have a coral reef in Fiji, and let's listen to that now.

(Soundbite of coral reef)


Mr. KRAUSE: That's a healthy coral reef, Ira. That's one that has maybe, oh, 15 or 16 species represented, lots of different fish and crustaceans and so on.

FLATOW: And so if we now listen to the next one, that's going to sound like this.

(Soundbite of coral reef)

FLATOW: Very different.

Mr. KRAUSE: That's a part of the same reef that's about, oh, a quarter-mile away, and that reef is beginning to die. And all you're hearing there are snapping shrimp and the surface noise of the waves.

FLATOW: So you really can, by listening to the environment, tell how healthy it is or whether it's headed down or not.

Prof. PIJANOWSKI: That's right.

Mr. KRAUSE: Yeah, an acoustic snapshot of 10 seconds can tell you whether a habitat is healthy or it's under stress or it's, you know, kind of destroyed altogether.

FLATOW: In how many places around the world are people collecting sounds like this?

Prof. PIJANOWSKI: Well, you know, there are efforts in Europe, Canada, United States, Japan, Australia, South America, Central America. There have been a lot of efforts.

Unfortunately, it hasn't been well-coordinated. We're hoping to do that in the near future here. There have just been just a lot of parallel efforts, and it's been very interesting to hear about, you know, new studies.

All of them are very similar to the ones that, you know, I've been doing, Stuart Gage at Michigan State and others, and what we want to do is begin to compare ecosystems around the world.

You know, sound is really one of those unifying variables that I've been searching for for most of my career here, being able to understand both the biological activity - how do the ecosystems function - but as well as human activities. What are humans doing on the landscape? Because we do make sound. And it really does kind of capture both of those.

FLATOW: Sounds very powerful. Sounds are very powerful, and at the same time, what you're doing is preserving for us sounds of a healthy world.

Prof. PIJANOWSKI: That's right. I mean, this is - the sounds that we have, and Bernie's had, for many, many years, are really - it's a digital record of the ecosystem. You know, it's - and sounds are really the heritage of our planet.

You know, what's really kind of disturbing is that, you know, many of the places that Bernie has gone and recorded, and he's just got some marvelous recordings from all over the world, him and his colleagues, many of those places no longer are in a natural state.

Mr. KRAUSE: Yeah, I'd like to point out, along with what Bryan is saying, that I've been recording since 1968. I've been recording soundscapes since 1968. And fully 50 percent of my archive comes from habitats that are no longer acoustically viable in a natural state, 50 percent.

FLATOW: Half of it's gone.

Mr. KRAUSE: Half of it's gone in my lifetime. That's just 40-some-odd years.

Prof. PIJANOWSKI: And, you know, one of the other aspects is that it is very difficult nowadays to go and find a place where it is indeed quiet, where we are only isolated with the natural sounds.

And so the spatial reach of the noise that we're producing all around the world is just continuing. It's just increasing. And so I think that's something that we need to pay attention to.

FLATOW: All right, we're going to come back and talk lots more with Bryan Pijanowski and Bernie Krause. Our number, 1-800-989-8255. We'll get you to listen to the sound of elephants trumpeting in the Congo when we come back and talk more about soundscape ecology, disappearing sounds reflecting disappearing ecosystems.

Stay with us. You can tweet us @scifri, @-S-C-I-F-R-I also. We'll be right back after this break.

(Soundbite of music)

FLATOW: You're listening to SCIENCE FRIDAY from NPR. I'm Ira Flatow. We're talking this hour about listening to soundscapes with my guests Bryan Pijanowski, associate professor of forestry and natural resources at Purdue; Bernie Krause, bio-acoustician and CEO and president of Wild Sanctuary in Glen Ellen, California. Our number, 1-800-989-8255. Let's go to Adeline(ph) in San Francisco. Hi, welcome to SCIENCE FRIDAY.

ADELINE (Caller): Hi, thanks for taking my call. I'm a musicologist. So I'm very interested to hear the specific terminology that's being used in this new field. It's really fascinating.

And I had two questions for the guests. First which was: Is there anything you could say you - the acoustic soundscape reveals to you that you can't get from just looking and being physically in the space and using your eyes?

And then the second question is: Have you enlisted the help of any musicologists or other musical experts in your research? And I'll take my answer off the air. Thank you.

FLATOW: Thank you. Bryan, Bernie?

Prof. PIJANOWSKI: Let me just jump in here. That's an excellent question. You know, one of the things that we're finding is that when we stick a microphone out and record continuously, we are recording things that are happening in the morning and in the afternoon, at night.

And one of the things that we reported in the article is that there's a lot of activity in the middle of the night. And so as ecologists we might be missing really an important part of the ecosystem. So there is quite a bit.

We have microphones down in Costa Rica in very, very remote areas. And so we can pick up a lot of different kinds of patterns that, just going out and looking, or just being there in a traditional survey, would not pick up.

Mr. KRAUSE: You know, one of the first subtitles of my new book, called "The Great Animal Orchestra," which - well, one of the first subtitles was "How Animals Taught Us to Dance and Sing."

And what the caller was referring to was, you know, what's the relationship kind of between the natural world sounds and music. It's exactly that.

You know, it's a collective - these collective voices of living organisms were the very things that inspired us and kind of invited us into song and dance in the first place. And it's really interesting to see how that all comes together.

Prof. PIJANOWSKI: Well, yeah, let me also comment that, you know, Murray Schaffer(ph) back in the '60s, a musician by training, really began talking about soundscapes and really defined the term.

But he also introduced a lot of other kinds of terms, like sound marks and key notes, that are very characteristic of different sounds in an ecosystem.

I also think that musicians are great listeners. I think as a scientist we have a lot to learn about kind of tuning our ears to nature. And I think musicians can help us a lot. A lot of musicians that I've talked to that have used natural sounds in recordings are great at setting up microphone systems in forested ecosystems, for example, in ways that really do capture, like, almost the three dimensions of sound.

So to answer the second part of that question: Yeah, I mean, I think there's a lot that can be learned from some folks in the humanities.

FLATOW: 1-800-989-8255 is our number. Do you have a catalog of these sounds, and are they available to any of us to listen to them, Bernie?

Mr. KRAUSE: Sure. They're on our website,, and you can see them. But there are also many catalogs out there of different kinds of ways of looking at the sonic world, the acoustic world. Some of them can be found in institutions like Cornell and others just from private individuals. There's some wonderful work out there.

Prof. PIJANOWSKI: Yeah, and our website, if you just go to Purdue Soundscape Ecology Project website, we have 156,000 recordings that you can go and you can query, you can - it's all online.

Every recording that we've made in Indiana and some in Costa Rica in collaboration with Conservation International have now been put on the Web, and you can go through and scroll and listen to and actually look at some of the visuals of the recording. So you can begin to listen and see at the same time.

FLATOW: Let me get to our final sound here. We have a sound of elephants trumpeting in the Congo.

(Soundbite of elephants)

FLATOW: You could have fooled me. They would have been lions if - it's like roaring, that trumpeting.

Mr. KRAUSE: What's amazing about them, Ira, is that we have 32 different kinds of elephant vocalizations from that very site.

FLATOW: Thirty-two?

Mr. KRAUSE: Yeah.

FLATOW: And each one has a separate use, I'm sure. If I were an elephant, I'd know.

Mr. KRAUSE: That's right.

Prof. PIJANOWSKI: You know, that also brings up another point, in that, you know, what we just listened to I think is fairly unique, you know, if you listen to the rest of the recording. What I worry about is that there are probably many other places around the world where we kind of have very unique soundscapes, and once they're gone, that's it. They're irreplaceable.

I do worry that we haven't paid enough attention, especially to what Bernie's been doing for these many years, and you know, half of his recordings no longer - you can no longer go to those places and listen to that. So I think we need to think about conservation of these soundscapes, and we haven't.

There is no plan to do that, and so I'm hoping maybe in the next 10 or 20 years - you know, maybe in SCIENCE FRIDAY from 10 years from now we can talk about what we've been doing about preserving these, but...

Mr. KRAUSE: You know something, Bryan? That's a great point. One of the things about that is that if we preserve the soundscape, we preserve the habitat.

Prof. PIJANOWSKI: That's right.

FLATOW: Let's go to Natalie(ph) in South Lake Tahoe. Hi, Natalie.

NATALIE (Caller): Hi.

FLATOW: Hi there.

NATALIE: How are you?

FLATOW: Go ahead.

Mr. KRAUSE: Doing great.

NATALIE: Yeah, I was in Darjeeling, India a couple of years ago, and I just -you had talked earlier in the show about the soundscapes of human activity and healthy ecosystems, and that just sort of hit me because we were staying on the second floor of a small hotel that was up above sort of a central square, and there were no cars, no mechanical vehicles around that particular area.

And it was a very unique sound that I had really never heard before, and it was very comforting because you were sort of part of this community. You could hear conversations going on. You could hear people selling in their shops. You could hear laughter. But none of it was very - you know, nothing stood out. It was just sort of a background, soft hum of activity.

Prof. PIJANOWSKI: Yes, go ahead.

NATALIE: Go ahead.

Prof. PIJANOWSKI: No, I was I'm getting excited about what you're just saying. I mean, there are other dimensions to what we're suggesting, and that is, you know, there are cultural soundscapes that are also important to humans, that we value them.

You can jump online and listen to some of ours. You know, the sounds of a church bell, for example, in a very rural area is something that's very pleasing, the sound of a market, the sound of a marina.

You know, there are human environments that are actually good. So, you know, one of the things we say in the article is that not all human-produced sounds are bad, and maybe we shouldn't even label them all as noise. They become part of the way in which we associate the human being with the landscape, with nature or the environment.

And so there is an acoustic link, and some of it's good that's related to human-produced sounds.

FLATOW: Can you tell from your sounds, evidence of global warming or climate change, from what you've been recording?

Prof. PIJANOWSKI: Well, you know, Bernie's done some of that work already. (Unintelligible) listened to it earlier.

Mr. KRAUSE: We've recorded in places like Alaska, where we actually see some evidence of global warming. I did a trip there in 2006 with two colleagues, Martin Stewart and Kevin Colver from Utah. And we found that when we were at these sites, the sites had already begun to be compromised by early warming.

And apparently the soundscape had changed quite a bit because there were many more birds of a particular species that shouldn't have been at some of the sites we were at, yet they were there.

And we can't make a direct link with global warming because we haven't done the baseline material studies to figure this out.

Prof. PIJANOWSKI: We're starting to do that, because we now have four years of continuous data around Purdue. But you know, some of the things we say in the article, there are a lot of organisms that are regulated by climate, by temperature - you know, insects and frogs, for example, amphibians.

So if we warm them - warm up the planet a little bit, then the timing of their chorusing and sound production will be earlier. And then there are other organisms that are more photo-period driven. So there could be a reshuffling of the soundscape as a result of climate change.

FLATOW: Gentlemen, I want to thank you for taking time to be with us today. Good luck, and thanks for sharing your sounds with us.

Prof. PIJANOWSKI: Thanks, Ira.

Mr. KRAUSE: Thank you.

FLATOW: Bryan Pijanowski, associated professor of forestry and natural resources at Purdue. Bernie Krause, a bio-acoustician and CEO and president of Wild Sanctuary in Glen Ellen, California, author of the upcoming book, "The Great Animal Orchestra.

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