This is Moraine Park, a large open valley in Rocky Mountain National Park. The accompanying MP3 file was recorded there as part of a National Park Service project to record natural soundscapes that are unspoiled by human sounds. The scientists making the recordings are working under the gun — such pure, natural, unspoiled soundscapes are increasingly difficult to find. It’s rare to spend more than an hour or two anyplace before manmade sounds intrude.
This particular recording, one of 70 so far, was made by Jacob Job, an acoustic biologist at Colorado State University. He carried some 30 pounds of equipment in his backpack, including a portable digital recorder, microphones, and batteries. This particular recording session lasted only about an hour before being interrupted by an airplane.
It takes very little to intrude on nature’s sounds. A distant highway, a passing hiker, or a plane far above. And yet these sounds disturb the wildlife and change their behavior.
Biologist Kurt Fristrup, creator of the park service’s soundscape project, explains:
“Imagine you’re an owl looking for your dinner,” Fristrup said. “A three decibel increase in sound level cuts in half the area in which you could hear those sounds, he said. “So you are half as efficient in finding food, with a relatively subtle increase in background sound level.”
Prey animals, like small birds, have a harder time hearing predators as the background decibels climb, and all animals need to hear to communicate.
We’re all familiar with light pollution. And air pollution has been found even in some of the most remote places on earth. But sound pollution is also a serious and growing problem. The park service developed this sound map:
WHAT SOUND LOOKS LIKE
A model was developed to understand relationships between measured sound levels and variables such as climate, topography, human activity, time of day and day of year. In general, the brighter the spot, the greater the sound intensity. (Source: National Park Service)
Fristrup is optimistic, however, that we can do better and that natural soundscapes can be preserved and restored. Awareness is the key. And the soundscape project is a beginning.
For more about the soundscape project, see National Public Radio’s “Beyond Sightseeing: You’ll Love The Sound Of America’s Best Parks” and the park service’s “Soundscape/Noise.” Also the park service’s “A Symphony of Trees, Grasses, Birds and Streams” and its link to “Enhance Your Soundscape.”