Listen to some of the natural sounds — and noise pollution — collected from America's national parks:
Songbirds in Yukon-Charley Rivers Natural Preserve (Alaska)
Owls and Insects in the Great Smokey Mountains National Park (North Carolina and Tennessee)
Wind at Grand Teton National Park (Wyoming)
Helicopter over Arches National Park (Utah)
Prop Plane over Arches National Park
Audio courtesy National Park Service
For four years, the National Park Service has been gathering natural sound in dozens of parks across the country. The idea is to protect visitors -- and wildlife -- from unwelcome noise.
So far, sound has been recorded in about 20 of the country's 388 national parks. The goal is not to preserve natural sound in recordings, but to have a baseline from which to preserve it in the wild.
The park service is essentially monitoring for noise pollution. It sees the natural soundscape as a resource -- for visitors, who repeatedly say in park surveys that they value it, and for wildlife.
"There are a lot of species of wildlife that are dependent upon the ability to hear sound, either to find food or avoid being someone else's food," says Karen Trevino, who heads the park service's Natural Sounds Program. She notes that some species use noise to find a mate, or to find shelter and safe nesting grounds.
Airplanes are a disruption in many parks, as are boats and snowmobiles. But Trevino says most sounds come from park service operations -- whether it's the rumble of laundry trucks or the jackhammer sounds from construction of roads and buildings. She says the park service is just starting to realize it needs to manage its own sound -- and that awareness is the first goal of the Natural Sounds Program.