CORTEZ, Colo. - Careful stewardship means visitors to the vast, sere landscape of Ute Mountain Tribal Park can easily imagine that the Ancestral Puebloans, who lived here until the late 13th century, just recently packed up and left. A tour through Mancos Canyon, the central valley of the 125,000-acre park, is a special experience - lively and interactive.
Members of the Ute Mountain Ute tribe, on whose reservation the park lies, continually work to stabilize the area;s historic structures - cliff dwellings, towers, kivas and more - and the paths leading to them. However, the tribe, whose ancestral range included Mancos Canyon, does not allow further interference with the landscape or its ancient patrimony.
There's no archaeological excavation, which is widely thought by Native people to destroy sites. Nor is there a modern tourism infrastructure, including sidewalks and buildings with running water, as is found at Mesa Verde National Park, which borders the Utes' park to the north.
In addition, visitorship is kept low.
''Because of the fragility of the sites, we have to control the number of tourists,'' said park director Veronica Cuthair, Ute Mountain Ute. Those visitors are escorted by tribal guides, and patrols prevent trespassing; both policies control looting.
As a result of the tribe's vigilance, Ute Mountain Tribal Park is in pristine condition, with varied shrubs and grasses watered by a river that rushes through its broad valley. Wildlife includes golden and bald eagles, wild turkeys, brown and black bears, antelopes and mountain lions. Wild horses trot by tour groups and peer curiously at the humans ogling them.
Piles of pottery sherds are simply everywhere. On the pots' surfaces, black-and-white painted designs have survived centuries of exposure to the high-altitude region's weather extremes and scorching sun. Redware is also present, as are gray pots with exteriors that were incised to create decorative corrugations; the ridges and valleys are also functional, as they increase the exposed surface area and thereby hasten cooking.
The tribe's knowledgeable tour guides explain the history, geology, botany and human use of the park from the Native point of view. On a recent trip, members of the tour group were uniformly impressed by the amount of information imparted, from ancient history to present-day issues, that is not available otherwise.
The guide that day, Marshall Deer, Ute Mountain Ute, offered his tribe's answer to the oft-repeated question about the ancient inhabitants of the Four Corners area: Why did they leave? ''People say the Ancestral Puebloans were completing a spiritual migration,'' Deer said. ''It wasn't a case of food or water shortage.''
Special highlights of the experience included an explanation of a rock art Creation Panel, also called the Butterfly Panel after one winged figure cut into the reddish rock face. Once a year, a shadow resembling a lizard, cast by a small nearby outcropping, crosses the panel. As the lizard crawls past Spider Woman, Kokopelli and more, it reveals this world's beginnings, interactions of gods and humans, an epic migration to the North Pole and back, prophesies for the future and predictions for crop germination in the growing season to come.
Other calendrical structures in the park include small towers that serve as solstice markers and a rough cliff face across which a snake-shaped shadow travels. As the shadow moves, it appears to open its mouth and swallow a man.
''These were created by the Ancestral Puebloans and pertained to practices and ceremonies at certain times of the year,'' Cuthair said.