DAVID GREENE, HOST:
And, you know, every place has its own sound.
(SOUNDBITE OF COYOTES)
GREENE: Those are coyotes in Colorado, recorded by the National Park Service as part of its project to capture natural soundscapes. We're doing a series on the centennial of the national parks.
And as part of that series, NPR's Christopher Joyce and audio producer Bill McQuay from the Cornell Lab of Ornithology went soundscaping. And they discovered how hard it is to escape the noise of humanity.
CHRISTOPHER JOYCE, BYLINE: Colorado's Great Sand Dunes National Park is like a 30-square-mile patch of the Sahara Desert that somehow ended up at the foot of snow-capped mountains. Bill and I arrived during a pounding hail storm and ducked into the park's visitor center.
We were there to meet biologist Kurt Fristrup. He's the mastermind of the park service's soundscape project. He arrived with hail stuck in his blond hair.
KURT FRISTRUP: The weather here can change very quickly. This particular thunderstorm - I thought a lot about trying to find cover.
JOYCE: Fristrup has collected a staggering amount of sound from more than 70 national parks. Bill and I wondered why. Fristrup explains that the Park Service has been concerned about human noise in national parks.
BILL MCQUAY: Helicopters, off-road vehicles, nearby road traffic, airplanes - the sound of us, basically.
JOYCE: Was it diminishing the park experience for people?
FRISTRUP: We're interested in you being able to hear the sound of a squirrel scurrying through the leaf litter a hundred feet away, you know, and other things like that. These are the small moments that can really connect you with the park.
MCQUAY: So Fristrup started putting microphones in the parks to detect human-made sound leaking in.
FRISTRUP: So the signature challenge for the Park Service is how you bring people to these places without destroying the essential qualities that made the park worth founding in the first place.
MCQUAY: As an audio producer, I also wanted to know how Fristrup's team captures soundscapes. I traveled about 250 miles north of Great Sand Dunes to Rocky Mountain National Park.
I hiked up into the high country with Jacob Job, a biologist with Colorado State University. Job carries a portable digital recorder, microphones, batteries - 30 pounds in his backpack. He looks for just the right place.
JACOB JOB: I don't feel like I see the place first. I feel like I hear the place first.
MCQUAY: Job and I set up our recorders on tripods in an area called Moraine Park. It's a grassy valley with sharp peaks all around.
JOB: I just had seen these small trees sitting out here. And I figured it might attract some birds. And sure enough, a bit of a wetland - all kinds of stuff.
MCQUAY: Soon we've gotten ravens, black birds - then, a group of wild turkeys walks right by us. Normally, Job collects several days of sound. Computers help sort through all of it. It's a lot of work but for Job, a work of love.
JOB: So I think if we start to lose sounds of wilderness, we start to lose a piece of us. And I think that really hits at us at a place - we don't really fully understand what is very important.
(SOUNDBITE OF PROPELLER PLANE)
MCQUAY: Less than an hour into our recording, the sound of a machine breaks the spell.
JOB: This is a prop plane. And this is one of the things we deal with on a constant basis. You kind of get - shift back into reality.
(SOUNDBITE OF PROPELLER PLANE)
JOYCE: Human-made sound is everywhere in parks. Fristrup's team found that on any given day, you can hear some form of it 25 percent of the time.
(SOUNDBITE OF TRAFFIC)
JOYCE: Even back at Great Sand Dunes Park, a place known for its silence, Bill and I had a heck of a time escaping human-made sound.
MCQUAY: Highway traffic and, of course, tourists, even on a cold, blustery day.
JOYCE: So we decided to climb up into the dunes with Fristrup. To do that, first, we had to cross a fast-moving, shallow stream.
(SOUNDBITE OF STREAM)
JOYCE: All right. I think I'm going to have to take my shoes off to do this.
Oh yeah, that's cold.
FRISTRUP: (Laughter) Straight from the mountain snows to you.
JOYCE: You approach this place. And what you see in front of you is this enormous sandbox.
FRISTRUP: It's so unusual. It looks unreal to me. It just looks strange, like it's been painted there. You can see there's depth, but the texture just is so odd.
JOYCE: That'll be blowing around 40 right now.
FRISTRUP: It is blowing.
JOYCE: Once we reach the dunes, we climb. They rise over 700 feet - the highest dunes in North America. We duck behind a dune.
Oh, nice and deep.
JOYCE: Oh, that's soft.
MCQUAY: Just below the crest of the dune, the howl of the wind dies to a whisper. The sand absorbs the sound like a sponge.
JOYCE: On a calm day, Fristrup says it's the kind of quiet that animals experience when we're not around. And that's something that Fristrup has been thinking about. Animals evolved for millions of years in natural soundscapes. How does our sound affect them?
He and other scientists have conducted experiments to test that idea. They found that if you add just a few decibels of unnatural sound, like a distant highway, it throws animals off-kilter.
FRISTRUP: I think it's in the 30s or 40 percent of the natural areas - sound levels are 3 dB higher than they would be. You imagine, you know, the owl looking for your dinner.
A 3 dB increase in background sound level cuts in half the area in which you could possibly hear those sounds. And so you're half as efficient in finding food with a relatively subtle increase in background sound level.
JOYCE: And prey animals, like small birds, have a harder time hearing predators. And all animals need to hear to communicate. Fristrup is optimistic, though, that park managers can do something about all this noise.
FRISTRUP: Natural soundscapes can be fully restored as soon as we are smarter about where we put our noise sources.
JOYCE: Electric vehicles are quieter. Planes can be routed away from parks. Off-road vehicles already are limited in some parks. And soundscapes are starting to win some respect.
A few years ago, an oil and gas operation wanted to drill near Great Sand Dunes. An environmental group argued that the Dunes's silence was unique and sued to stop the project. And a judge agreed.
FRISTRUP: It's not a common story here in the - out in the West. But this is one of the cases where noise actually played a role in land use decisions.
JOYCE: Fristrup says soundscapes can be protected.
FRISTRUP: The good news is that there are a lot of places where those noise events are infrequent enough that you get many, many minutes - sometimes a few hours - of noise-free time.
MCQUAY: So next time you're in a national park, stop...
JOYCE: ...And listen. Christopher Joyce, NPR News.
MCQUAY: And Bill McQuay, Cornell Lab of Ornithology.
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