A green-tailed towhee is down in the canyon, hidden amid the green leafy oaks, singing his heart out as all male towhees do. I am in Colorado’s Mesa Verde National Park, gazing at the spectacle of Cliff Palace.

Just then, a ranger appears announcing some spare tickets to Cliff Palace; someone, it seems, has reconsidered the precipitous descent into and out of the canyon and surrendered their ticket. A moment later, I am headed down the steep trail to the canyon floor, out of the hard summer sun, to where a cool draft belches from within the cavern.

Our guide to Cliff Palace is a young Native American woman park ranger. She stands among the tourist throng in her crisp uniform and Smokey Bear hat; there, in the shade of the overhanging sandstone walls, she lectures about the Ancestral Puebloans who lived here before they abruptly departed.

The elaborate stone-built pueblos such as Cliff Palace were constructed probably between 1190 and 1280, and then they were abandoned by 1300. At Cliff Palace, household items were left in place as the people departed, moccasins, cooking utensils, jewelry, tools, all discarded. The ranger relates how the people eked out a living here, growing maize and beans up on the mesas, hunting mule deer and other game, domesticating wild turkeys. They collected water in pots from snowmelt and the infrequent rains running offthe cliff walls, and all these provisions they stored in recesses in the cliff, carefully walled off to exclude rodents and insects.

Tree-ring analysis has shown that a sustained drought afflicted the region in the last quarter of the 1200s, right around the time when the cliff dwellings were abandoned. When the time came that there was no runoff to collect and store, the springs that made the canyons such attractive living sites would also have gone dry.

The inhabitants of Cliff Palace even trekked to the distant Mancos River to fetch water. Perhaps, that, too, went dry. A marginal existence would have become untenable. All that they had labored to construct, the towers, their subterranean round ceremonial rooms or kivas, the storerooms, all were abandoned. Without water, there could be no life.

I wander about the pueblo, taking pictures. An athletic-looking woman in a tank top has cornered our guide. She is inquiring about the guide’s ancestors, whether they came from Asia across the land bridge of the Bering Strait. No, replies Smokey Bear Hat Woman, this is not the case. In fact, explains Bear Hat Woman, her ancestors emerged from the underworld through a hole in the Earth. A symbolic facsimile of this portal, called a sipapu, can be seen in the floor of every kiva.

She goes on to suggest that Tank Top Woman can see this hole for herself if she would care to have a look down into the kiva. Tank top Woman is not inclined to see for herself. She has her arms folded, her head cocked; she smiles blandly. Bear Hat Woman remains steadfast in this matter.

This year in Colorado, the rains came back. Prairie sunflower and western spiderwort were in abundance on my property. I had never seen so much blue-grama grass, lush bunches with tall, violet seed heads. The earth drank deeply. Even so the hills were riddled with drought-killed lodgepole pines; the rivers finally ran lean, as irrigation gobbled up the flows. Even in a time of rain, there are lawns to water, sugar beets to irrigate, powerboats to float, cars to wash and wash again.

I hang back at Cliff Palace as the others leave. Finally, I follow Bear Hat Woman up the pine ladders that exit the canyon. Halfway up the ladders, Bear Hat Woman pauses upon the wooden rungs. She points out to me the pecked hand and toe-hold trail used by the ancestral Puebloans to climb into and out of the canyon. I try to imagine women in moccasins or bare feet, with water pots in hand and children strapped to their backs, padding across the exposed slabs.

"You can still see where the old ones touched the rock," she tells me. She lays her hand upon the nearest hold, the tips of her three middle fingers fit seamlessly into the impressions there. Then she departs, up the ladder. Below me, amid the canyon’s oaks, the towhee has resumed his song.

Rob Cordery-Cotter is a contributor to Writers on the Range, a service of High Country News (hcn.org). He is a veterinarian and writer in LaPorte, Colorado.