WASHINGTON (AP) — The call of the wild is getting harder to hear.
A new study says peaceful, natural sounds are sometimes being drowned out by noise caused by people in many of America's protected parks, forests and wilderness areas.
Researchers measured sounds at 500 spots — from city parks to federal wilderness. They calculated that in nearly two-thirds of the Lower 48's parks, noise can at times be twice the natural background level because of airplanes, cars, logging, mining and oil and gas drilling.
Colorado State University biologist George Wittemyer says people hear only half the sounds that they would in natural silence. He says noise pollution can hurt wildlife looking for mates and food even though it may still seem quiet as a library.
The study is in Thursday's journal Science.