Every few years a bison attempts to cross Blacktail Pond in Yellowstone National Park only to discover too late that the ice has thawed. The bison drowns and sometimes, like last spring, a grizzly bear finds its carcass.
The bear visited the carcass at night, so that’s when Jennifer Jerrett loaded her recording equipment, parked her car a safe distance from the carcass and pushed a microphone out the window. She hit record and waited, hoping that she was both far enough to not disturb the bear, and close enough for her mic might pick up the sounds of it eating.
It’s hard to describe what it was like, sitting in a car and listening to a bear feed, but Jerrett doesn’t have to find words for the sound, you can listen to the animal’s gnawing in the park’s new sound library. It is one of about 80 recordings documenting the park’s soundscapes. It’s part of a project created through a partnership with Montana State University’s library, its Acoustic Atlas and Yellowstone National Park.
“These are ecological oral histories,” Jerrett said. “Landscapes are changing. Soundscapes are changing. It’s important to document what’s out there because it might go away.”
The project grew out of the Acoustic Atlas’ efforts to document sound in the Greater Yellowstone Ecosystem, said Molly Arrandale, program manager with the Acoustic Atlas. They partnered with Yellowstone to expand the sound library with offerings from the park.
Sound recordings are important to a variety of academic disciplines at the university. There is a researcher at Montana State who studies social predator vocalization and another investigating how natural sound impacts emotional and physical health in humans, Arrandale said.
Another goal is simply having a sound archive to share with people who can’t make it to the park but still want to listen to mud pots or birds or animals.
Jerrett traveled most of the main thoroughfares in the park this year, collecting any natural sound she heard. She recorded elk bugling, bison bellowing and geysers erupting.
“At first I wasn’t such a thermal feature kind of person,” she said. “I was into animals, but once I started recording, I realized each one of these features has its own voice.”
Veteran Geyser sounds like someone breathing deep and hard as it emits an eerily human sound.
Black Sand Pool releases imploding bubbles.
“It’s a sound you almost feel in your body rather than hear the low frequency bangs,” Jerrett said.
Then it changes to smaller bubbles that start to fizz.
Beehive is irregular, so catching it takes luck. But once it starts you can’t mistake its sound. It sounds like a freight train. “It’s a crazy, crazy geyser — it’s so loud,” Jerrett said. “It was so hard not to squeal or make a joyful sound.”
Much of her wildlife recording depends on luck. While traveling in the backcountry in the southeastern arm of the park, she recorded an adult bald eagle returning to its nest to feed its young. Her microphone captured the baby bird getting more excited as the parent nears.
The sounds Jerrett captures can help scientists. Every species has a range of vocalizations and regional dialects. It documents not just the vocalization of species, but also when they show up in specific places, or where certain birds and wildlife are absent, Jerrett said.
The recordings also are meant to connect people to the park.
“There is something completely different when you just listen compared to watching a video,” she said. “I think because you are inventing the images in your own mind, you are more of a participant in the story, rather than sitting back and watching it and letting it visually wash over you. It’s a very intimate experience and I think it’s an important one.”
Jerrett, who has a background in public radio, moved to the area with her husband, who works for the National Park Service. In addition to building up the park sound library, she’s also producing a series of podcasts focused on science in Yellowstone. The first, called “To Catch a Loon,” weaves together sounds she’s recorded of the birds, along with the story of those trying to help restore its dwindling population.
“It will absolutely change the way you think about birders in their little khaki jackets with binoculars,” she said.
Jerrett thinks Yellowstone is one of only a few parks building sound libraries and might be the only to start its own podcast.
The project is funded by grants, Montana State University, the Yellowstone Association and the National Park Foundation for at least one more year, but the project could be ongoing. There are so many sounds in the park it could take years to capture them all, Jerrett said. “I could easily do this for the rest of my life.”