Hike of the Month

Ajo Mountain Drive is closed, washed out by heavy summer rains, when photographer Jack Dykinga and I arrive at Organ Pipe Cactus National Monument headquarters one early December day. But we're in a four-wheel-drive pickup and on assignment, so with a dispensation granted by the park superintendent, we go in.

Now, at midmorning the next day, I'm hiking up Estes Canyon Trail, listening.

No one, absolutely no one, is here. Nearby, a wood-pecker hammers a saguaro trunk; a raven, wings soughing, cruises past, checking me out; a cactus wren calls from across the canyon. And another sound - a scarcely audible hum - that I can neither pinpoint nor identify.

The hum becomes louder, but only slightly, as I draw closer to the palisades of the Ajo Mountains. I sit atop a flat rock beside the trail, listening hard. Jack is far behind, down trail. I left him mounting his camera on a tripod, engrossed in the red glow of sunlight breaking across the spines of an organ pipe cactus.

I hear that low-volume hum again. The atmosphere is almost stone still. Only the slight trembling of feathery acacia leaves betrays the least breath of wind. But it is air I hear - I'm finally certain of that - air moving in and around, through, and over crevices, folds, knobs, and hollows of the yawning escarpment above me.

It's like no sound I've heard before, and only my isolation and the utter silence of the wilderness permits me to hear it now. How do I describe it? Except for its deep resonance, it's like the sound emanating from a seashell, like a long, breathless one-note incantation chanting “aahhmmm.” it now. How do I describe it? Except for its deep resonance, it's like the sound emanating from a seashell, like a long, breathless one-note incantation chanting “aahhmmm.”

EERIE WIND SONGS GREET HIKERS ON THE TRAIL

Fifteen minutes later, Jack rejoins me. “Did you hear the hum?” My question draws a blank stare. He heard nothing.

TO BULL PASTURE

We continue our 2.3-mile hike up Estes Canyon to Bull Pasture. The route winds back and forth across the canyon bot-tom before switchbacking up a steep ridge to link with a short spur up to the pasture. In places where last summer's torrential rains turned the trail into a temporary watercourse, the path is deeply gullied or littered with loose rock.

We pick our way to the top of the ridge, then begin a steep climb below a long cliff face to Bull Pasture. The air is crisp, the sun bright. A white-tailed deer, spooked by our approach, bounds up the trail ahead of us.

Above 3,000 feet, juniper trees sprout from cracks and crannies in the rocks. They're relicts of an era 10,000 years ago when the climate here was cooler and wetter. Like the junipers, the few desert bighorn sheep surviving in the Ajo Mountains cling to the highest ridges where temperatures are lower and rainwater for drinking is trapped in natural catchments.

Bull Pasture is an oval basin cupped between high ridges. Its luxuriant grasses inspired early ranchers to drive cattle up to graze in this high-country meadow. We stop for lunch at the summit above the pasture, welcoming the warmth of the full winter sun.

As we're packing to hike down the Bull Pasture Trail, I spot a red-tailed hawk. It sails in, directly overhead, traveling fast, casting a quick glance in our direction as it whistles past. The return trip along the Bull Pasture Trail is shorter by a half-mile than the way we came up.

At midmorning the following day, I'm alone, back on my rock in Estes Canyon, listening for the hum. I wait. It's breezier today. During a lull, I cock an ear toward the cliffs, straining to hear. Nothing. I'll try again next time.

WHEN YOU GO

From Tucson, take State Route 86 west to State 85 and turn south; from Phoenix, Interstate 10 to State 85 and turn south. Visitors to Organ Pipe Cactus National Monument must check in at monument headquarters, approximately 79 miles south of Gila Bend and five miles north of Lukeville, and pay a daily fee. Information on road conditions, trail-access, maintenance, and special conditions may be obtained there.

The best times to hike anywhere in Organ Pipe are spring, fall, and winter. Only very experienced desert hikers should attempt summer hiking.

Always carry plenty of water. An absolute minimum for desert hiking is one quart per person - a gallon in hot, dry weather. Extras: camera, binoculars, trail food, a sweater, and a windbreaker.