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  • (Nature sounds)

  • When I first began recording wild soundscapes

  • 45 years ago,

  • I had no idea that ants,

  • insect larvae, sea anemones and viruses

  • created a sound signature.

  • But they do.

  • And so does every wild habitat on the planet,

  • like the Amazon rainforest you're hearing behind me.

  • In fact, temperate and tropical rainforests

  • each produce a vibrant animal orchestra,

  • that instantaneous and organized expression

  • of insects, reptiles, amphibians, birds and mammals.

  • And every soundscape that springs from a wild habitat

  • generates its own unique signature,

  • one that contains incredible amounts of information,

  • and it's some of that information I want to share with you today.

  • The soundscape is made up of three basic sources.

  • The first is the geophony,

  • or the nonbiological sounds that occur

  • in any given habitat,

  • like wind in the trees, water in a stream,

  • waves at the ocean shore, movement of the Earth.

  • The second of these is the biophony.

  • The biophony is all of the sound

  • that's generated by organisms in a given habitat

  • at one time and in one place.

  • And the third is all of the sound that we humans generate

  • that's called anthrophony.

  • Some of it is controlled, like music or theater,

  • but most of it is chaotic and incoherent,

  • which some of us refer to as noise.

  • There was a time when I considered wild soundscapes

  • to be a worthless artifact.

  • They were just there, but they had no significance.

  • Well, I was wrong. What I learned from these encounters

  • was that careful listening gives us incredibly valuable tools

  • by which to evaluate the health of a habitat

  • across the entire spectrum of life.

  • When I began recording in the late '60s,

  • the typical methods of recording were limited

  • to the fragmented capture of individual species

  • like birds mostly, in the beginning,

  • but later animals like mammals and amphibians.

  • To me, this was a little like trying to understand

  • the magnificence of Beethoven's Fifth Symphony

  • by abstracting the sound of a single violin player

  • out of the context of the orchestra

  • and hearing just that one part.

  • Fortunately, more and more institutions

  • are implementing the more holistic models

  • that I and a few of my colleagues have introduced

  • to the field of soundscape ecology.

  • When I began recording over four decades ago,

  • I could record for 10 hours

  • and capture one hour of usable material,

  • good enough for an album or a film soundtrack

  • or a museum installation.

  • Now, because of global warming,

  • resource extraction,

  • and human noise, among many other factors,

  • it can take up to 1,000 hours or more

  • to capture the same thing.

  • Fully 50 percent of my archive

  • comes from habitats so radically altered

  • that they're either altogether silent

  • or can no longer be heard in any of their original form.

  • The usual methods of evaluating a habitat

  • have been done by visually counting the numbers of species

  • and the numbers of individuals within each species in a given area.

  • However, by comparing data that ties together

  • both density and diversity from what we hear,

  • I'm able to arrive at much more precise fitness outcomes.

  • And I want to show you some examples

  • that typify the possibilities unlocked

  • by diving into this universe.

  • This is Lincoln Meadow.

  • Lincoln Meadow's a three-and-a-half-hour drive

  • east of San Francisco in the Sierra Nevada Mountains,

  • at about 2,000 meters altitude,

  • and I've been recording there for many years.

  • In 1988, a logging company convinced local residents

  • that there would be absolutely no environmental impact

  • from a new method they were trying

  • called "selective logging,"

  • taking out a tree here and there

  • rather than clear-cutting a whole area.

  • With permission granted to record

  • both before and after the operation,

  • I set up my gear and captured a large number of dawn choruses

  • to very strict protocol and calibrated recordings,

  • because I wanted a really good baseline.

  • This is an example of a spectrogram.

  • A spectrogram is a graphic illustration of sound

  • with time from left to right across the page --

  • 15 seconds in this case is represented

  • and frequency from the bottom of the page to the top,

  • lowest to highest.

  • And you can see that the signature of a stream

  • is represented here in the bottom third or half of the page,

  • while birds that were once in that meadow

  • are represented in the signature across the top.

  • There were a lot of them.

  • And here's Lincoln Meadow before selective logging.

  • (Nature sounds)

  • Well, a year later I returned,

  • and using the same protocols

  • and recording under the same conditions,

  • I recorded a number of examples

  • of the same dawn choruses,

  • and now this is what we've got.

  • This is after selective logging.

  • You can see that the stream is still represented

  • in the bottom third of the page,

  • but notice what's missing in the top two thirds.

  • (Nature sounds)

  • Coming up is the sound of a woodpecker.

  • Well, I've returned to Lincoln Meadow 15 times

  • in the last 25 years,

  • and I can tell you that the biophony,

  • the density and diversity of that biophony,

  • has not yet returned to anything like it was

  • before the operation.

  • But here's a picture of Lincoln Meadow taken after,

  • and you can see that from the perspective of the camera

  • or the human eye,

  • hardly a stick or a tree appears to be out of place,

  • which would confirm the logging company's contention

  • that there's nothing of environmental impact.

  • However, our ears tell us a very different story.

  • Young students are always asking me

  • what these animals are saying,

  • and really I've got no idea.

  • But I can tell you that they do express themselves.

  • Whether or not we understand it is a different story.

  • I was walking along the shore in Alaska,

  • and I came across this tide pool

  • filled with a colony of sea anemones,

  • these wonderful eating machines,

  • relatives of coral and jellyfish.

  • And curious to see if any of them made any noise,

  • I dropped a hydrophone,

  • an underwater microphone covered in rubber,

  • down the mouth part,

  • and immediately the critter began

  • to absorb the microphone into its belly,

  • and the tentacles were searching out of the surface

  • for something of nutritional value.

  • The static-like sounds that are very low,

  • that you're going to hear right now.

  • (Static sounds)

  • Yeah, but watch. When it didn't find anything to eat --

  • (Honking sound)

  • (Laughter)

  • I think that's an expression that can be understood

  • in any language.

  • (Laughter)

  • At the end of its breeding cycle,

  • the Great Basin Spadefoot toad

  • digs itself down about a meter under

  • the hard-panned desert soil of the American West,

  • where it can stay for many seasons

  • until conditions are just right for it to emerge again.

  • And when there's enough moisture in the soil

  • in the spring, frogs will dig themselves to the surface

  • and gather around these large, vernal pools

  • in great numbers.

  • And they vocalize in a chorus

  • that's absolutely in sync with one another.

  • And they do that for two reasons.

  • The first is competitive, because they're looking for mates,

  • and the second is cooperative,

  • because if they're all vocalizing in sync together,

  • it makes it really difficult for predators like coyotes,

  • foxes and owls to single out any individual for a meal.

  • This is a spectrogram of what the frog chorusing looks like

  • when it's in a very healthy pattern.

  • (Frogs croaking)

  • Mono Lake is just to the east of Yosemite National Park

  • in California,

  • and it's a favorite habitat of these toads,

  • and it's also favored by U.S. Navy jet pilots,

  • who train in their fighters flying them at speeds

  • exceeding 1,100 kilometers an hour

  • and altitudes only a couple hundred meters

  • above ground level of the Mono Basin,

  • very fast, very low, and so loud

  • that the anthrophony, the human noise,

  • even though it's six and a half kilometers

  • from the frog pond you just heard a second ago,

  • it masked the sound of the chorusing toads.

  • You can see in this spectrogram that all of the energy

  • that was once in the first spectrogram is gone

  • from the top end of the spectrogram,

  • and that there's breaks in the chorusing at two and a half,

  • four and a half, and six and a half seconds,

  • and then the sound of the jet, the signature,

  • is in yellow at the very bottom of the page.

  • (Frogs croaking)

  • Now at the end of that flyby,

  • it took the frogs fully 45 minutes

  • to regain their chorusing synchronicity,

  • during which time, and under a full moon,

  • we watched as two coyotes and a great horned owl

  • came in to pick off a few of their numbers.

  • The good news is that, with a little bit of habitat restoration

  • and fewer flights, the frog populations,

  • once diminishing during the 1980s and early '90s,

  • have pretty much returned to normal.

  • I want to end with a story told by a beaver.

  • It's a very sad story,

  • but it really illustrates how animals

  • can sometimes show emotion,

  • a very controversial subject among some older biologists.

  • A colleague of mine was recording in the American Midwest

  • around this pond that had been formed

  • maybe 16,000 years ago at the end of the last ice age.

  • It was also formed in part by a beaver dam

  • at one end that held that whole ecosystem together

  • in a very delicate balance.

  • And one afternoon, while he was recording,

  • there suddenly appeared from out of nowhere

  • a couple of game wardens,

  • who for no apparent reason,

  • walked over to the beaver dam,

  • dropped a stick of dynamite down it, blowing it up,

  • killing the female and her young babies.

  • Horrified, my colleagues remained behind

  • to gather his thoughts

  • and to record whatever he could the rest of the afternoon,

  • and that evening, he captured a remarkable event:

  • the lone surviving male beaver swimming in slow circles

  • crying out inconsolably for its lost mate and offspring.

  • This is probably the saddest sound

  • I've ever heard coming from any organism,

  • human or other.

  • (Beaver crying)

  • Yeah. Well.

  • There are many facets to soundscapes,

  • among them the ways in which animals taught us to dance and sing,

  • which I'll save for another time.

  • But you have heard how biophonies

  • help clarify our understanding of the natural world.

  • You've heard the impact of resource extraction,

  • human noise and habitat destruction.

  • And where environmental sciences have typically

  • tried to understand the world from what we see,

  • a much fuller understanding can be got from what we hear.

  • Biophonies and geophonies are the signature voices

  • of the natural world,

  • and as we hear them,