It was John Muir, the great evangelist of America's wilderness, who warned: "The gross heathenism of civilization has generally destroyed nature."

The National Park Service made no mention of heathenism, but its concern was clear when it imposed a ban on the use of noisy airborne drones by visitors intent on adding an extra dimension to the majesty of the nation's 401 national parks and monuments. The ban is a temporary measure while the service figures out a policy on how to deal with this gnatlike advance of aeronautics that already has been pestering hikers, climbers and campers.

Park officials described how the sunset serenity of a group at the edge of the Grand Canyon was suddenly interrupted in April by a loud and intrusive drone that careered about before crashing into the canyon wall. Then there was the drone that rose up uninvited to hover before the four presidents carved into Mount Rushmore, then swooped down to buzz perilously close to hundreds of people seeking something more contemplative.

The Park Service was wise to act early. The retail price of drones is falling, and they are fast becoming toys of choice, with built-in temptations for mischief. Ordinary hobbyists can now buy them for several hundred dollars or less, store them in the car trunk, then radio-control the copter-bladed crafts on 40-minute flights hundreds of feet through the skies.

Officials need time to craft a wise policy, one that may involve a permit system and would allow drone use by emergency crews, research scientists and others with useful missions. The Park Service's drone challenge is not easy, as officials consult a variety of voices and interests. Even so, the parkland voice they must heed first is John Muir's: "Go quietly, alone; no harm will befall you."

FROM AN EDITORIAL IN THE NEW YORK TIMES