Preserving the Quietest Places
Dawn beckoned. The sun inched over the horizon of northern Colorado as Jacob Job and I twisted through a canyon en route to Rocky Mountain National Park. Over the rumble of his blue Ford F-150, he ticked off a list of rules for us to follow in the forest:
Move like a sloth: slowly and only when necessary.
If you need to turn, do so from your waist.
Don’t bend your wrists, ankles, fingers — they crack.
Calm your breath.
If you sit down, lean against a tree, unfurl your legs, and don’t fidget.
“You don’t realize how much you hear of yourself,” said Job, 33, a dark-haired beanpole in a brownish T-shirt and olive cargo shorts. “Your breathing, your clothes moving, your joints popping, the sound of you swallowing.” Only by staying quiet — melt-into-the-forest quiet, hear-twigs-snap-and-insects-buzz quiet — could we find the distinctive trill that had so far eluded him: Troglodytes pacificus, the Pacific wren.
Job works for the National Park Service and Colorado State University as part of a small team that experiences nature not through granite peaks and stunning vistas, but through soundscapes. His back seat was hidden beneath a heap of fuzzy microphones, one so large that a passer-by mistook it for a dog. He’d spent months hauling them deep into the park’s thicket of ponderosa pines and Douglas firs to capture the geologic, animal, and man-made mixtape that can signal whether and how an ecosystem is changing.
Listen when we’re out there, he told me. Really listen.
Nature’s melodies trigger something in us. No one is sure exactly how or why. One theory is that, outdoors, silence — total silence — signals danger. Whatever muzzled those animals can’t be good. By extension, natural sounds reassure us: It’s safe here. Park surveys repeatedly show most visitors are seeking enough solitude to hear birds chirp and leaves crackle. And research suggests those sounds could potentially aid in mood recovery — but only when there are no synthetic interruptions.
Researchers have studied the overlay of noise and nature for some time, but in a very narrow way — mainly, how specific species communicate. But in recent years, scientists have widened their focus to entire ecosystems, essentially treating soundscapes as extensions of landscapes, and noise as a potential contaminant. “Pollution isn’t limited to matter. It isn’t limited to particulates and chemicals and compounds,” said Kurt Fristrup, who oversees science and technology in the park service’s Natural Sounds and Night Skies Division. We were chatting at his office in Fort Collins, Colorado — a labyrinth of cubicles near a workroom where tables and shelves groaned with sound meters, batteries, and even a “sound thermometer” that, from the side of a road, warns cars when they’re making a racket.
The sounds program was created in 2000, the result of the long-running battle over planes and helicopters that swoop tourists to the Grand Canyon and other sights. A new law had tasked park and aviation officials with mapping out air-tour management plans. In 2005, when Fristrup arrived from Cornell University, recording was about as efficient as lugging a stereo system into the backcountry. Technology eventually whittled down the heft and cost for his team and, more broadly, helped give rise to a new field of scientific inquiry.
So named in scientific literature only in 2011, soundscape ecology asks a range of questions that, until recently, have been underexplored. How do soundscapes vary across vegetation, temperatures, elevations? Does human noise alter animal behavior — and vice versa? “You can shut your eyes, but you don’t shut your ears,” Peter Newman, who runs the Recreation, Park, and Tourism Management department at Penn State University, told me. “Even when you’re asleep, you’re listening, and you’re listening because as an animal you’re saying, ‘Am I about to be eaten? Is the love of my life around the corner?’”
Research suggests noise can rattle an ecosystem. Birds, for example, rely on their voices to woo mates, size up rivals, scrounge for dinner. Horn blasts and engine revs can scramble auditory cues. Birds try singing louder, singing at a higher frequency, singing at night. Some abandon their nests altogether. This can trigger an ecological cascade, one that extends even to vegetation; noise can scare away some birds that would normally scatter seeds.
The Natural Sounds and Night Skies Division and the researchers it’s affiliated with help shape how park units are run. Their work, for example, is the reason California’s Muir Woods christened a popular redwood grove a quiet zone; Newman, Fristrup, and others found doing so was, in terms of noise levels, the equivalent of cutting the number of visitors by 28 percent. When an energy company wanted to drill outside Colorado’s Great Sand Dunes, a park likely as hushed as it was before European colonization, a federal judge cited preserving its “significant ‘sense of place’ and quiet” as a reason to halt the project.
Fristrup’s team has quantified how precious that kind of stillness is. At least 83 percent of land in the continental U.S. is within two-thirds of a mile of a road, and domestic passenger flights have more than tripled since the early ’80s. The park service recently released a color-coded map, based on recordings from hundreds of sites, that shows estimated sound levels in the lower 48. The East Coast is confettied with yellow — that’s high-decibel noise. Though much of the West is as blue as a mountain lake — meaning it’s far quieter — on average, you’ll still hear the drone of aircraft 15 minutes of every hour. In the Mojave Desert, flights to and from Las Vegas are to blame. In the Sonoran Desert, it’s border patrol operations.
Before our trip, I met Job across town from the park service office, on the leafy campus of Colorado State. He runs a listening lab that the park service and university share: Room 015 of the JVK Wagar building, an almost windowless space with a half-dozen computer stations. Under photos of Lassen, Isle Royale, and other natural scenes — and a large green-and-white banner asking, Did You Hear That? — students gaped at screens; their noise-canceling headphones had drowned out my arrival.
Job leaned over a desk with two monitors and a handful of hard drives scattered about; each held the sounds of roughly one park. “Where do you want to travel to?” he joked. We headed to Alaska. Job clicked open a folder of photos: a sound-monitoring station in Denali National Park. At Wolf Creek, a stream burbled through trees in an area so remote that the recording equipment had to be helicoptered in. If everything goes smoothly (a bear futzing with a station is not unheard of), a recorder hums along for 30 days. Then Colorado State students listen to snippets of audio and label noise they hear with a number: 2.3 is a bus, 3.3 a jet ski, 5.2 a train whistle, 7.2 a leaf blower.
Job cued up a spectrogram, a visual representation of the time, frequency, and amplitude of sound; it resembled some modern-art splatter of yellow and blue paint. When he first played the underlying recording — a low hum on a summer day at Wolf Creek — I felt like I’d wandered into a country whose language I didn’t speak. Sounds blobbed together, nearly indecipherable.
“There are lakes around us. What do lakes mean in the bush country in Alaska? What do they hold the potential for?” Job asked me.
“Fishing?” I said.
“If there’s fishing, how do people get there?”
I’d heard, apparently, a prop plane (on the code sheet, 1.2). If you do this long enough, it changes how you listen, inside and outside. Job can’t go hiking without noticing rumbling overhead and thinking, 1.1, 1.1 — the code for a jet.
Job became interested in birdsong as a kid in southern Michigan, memorizing the calls of birds that swooped through his yard. Eventually, he started taping them the same way he taped his favorite songs off the radio — by waiting patiently with a boombox, ready to press record. He’s since learned the sounds of several hundred birds, but he cherishes one the most: the common loon, whose haunting yodel whisks him back to the Midwest. It inspired his license plate (
CMNLOON) and his Instagram handle (@gavia_immer, the loon’s Latin name). His girlfriend is also a bird lover, and he recently crept up to her office window, raised his phone, and serenaded her — à la Say Anything — with a loon recording.
A while back, Job read a National Audubon Society report about the likely effects of climate change on North American birds. It was terrifying. “I was like, if that’s going to happen, we really need to document the biodiversity we have in place now to track that change,” he recalled. “To have it as acoustic fossils if we do lose them.” He began cataloging the birds and the broader soundscapes at Rocky, as folks here call the park — a sort of aural snapshot. Tracking down the Pacific wren was part of that quest. He’d tried, and failed, to find it earlier in the summer, but birders had been tittering online that the wren had resurfaced.
Two days later, we parked at Rocky’s Wild Basin Trailhead, the start of a 1.8-mile huff to Calypso Cascades. Rocky is the nation’s only park where commercial air tours are banned, and a few years ago, aviation officials grouped flights over one section of the park to lower noise levels elsewhere. But there will always be a certain amount of clamor: About 4 million people trekked through Rocky last year. Some residents of gateway town Estes Park refuse to hike after 7 a.m.; by 8:30, their favorite paths are mobbed.
Job and I had started a little after 6:30. He’d slipped on an orange backpack and black headphones and carted a large microphone that bore a striking resemblance to its nickname, Dead Badger. We had the pine-shaded trail to ourselves, though he bristled at the creek thrumming alongside us. That made it harder to pinpoint the wren, a speck of a bird that’s usually found in the tangled underbrush of Washington state and Oregon; its detour to Colorado has baffled park officials.
When we reached the trail’s end, Job slipped into quiet mode, and he reminded me of those street performers who mimic robots. His right arm was bent, elbow suctioned to his side, Dead Badger pointed straight ahead. When he scanned the foliage, he turned at his waist, just as he’d told me to do, raising his heel only when he needed to rotate further.
Before this, I’d been the kind of hiker who frustrated Job: hiking more with my eyes than my ears, paying little mind to the outdoor soundscape. But I tried his way of listening, and almost instantly everything sharpened. I noticed light glinting off spider webs, leaves rustling, a branch needling my right arm.
We wandered off the trail. The forest thinned, and the sun beat down, and the towering aspens and pines resembled the back of an amphitheater. That’s when we heard it: high-pitched, melodic — the chipper aria of a wren. For one thrilling moment, nothing else existed.