Between 1909 to 1985, Buenos Aires Ranch changed ownership numerous times, becoming a prominent livestock operation in Arizona with award-winning quarter horses and purebred Brangus cattle. In 1985, the U.S. Secretary of the Interior declared Buenos Aires Ranch a national wildlife refuge, with a focus on protecting the endangered masked bobwhite. Since then, refuge personnel, biologists, volunteers, and collaborators have worked together to revive the native semidesert grasslands and reintroduce indigenous wildlife to their historic environment.

Historically, the Altar Valley thrived as grasslands with abundant pronghorn herds. However, with the emergence of settlements in the 1860s, the balance of the ecosystem was disrupted. Overgrazing stripped the land, and the disappearance of grass and the suppression of natural fires allowed mesquite to dominate. The Altar Valley Conservation Alliance is working on a mesquite clearing project on the semi-desert grassland in the southern portion of the Altar Valley.  You may see piles of mesquite during your ride. [NPS]

With over 180 species, prickly pear cactus thrive from southern Canada to Patagonia. Members of the cactus family, prickly pear are vital food sources for various animal species including deer, insects, birds, rodents, javelinas, and coyotes. These cacti have also been utilized since ancient times by humans, with at least 15 species extensively consumed by humans. The Aztecs selectively bred certain species over millennia, yielding spineless varieties with exceptionally sweet, high-sugar content fruits.

The Soaptree Yucca has a multitude of uses. Indigenous communities utilized the fiber from the leaves of this yucca species for a variety of items like sandals, belts, cloth, baskets, cords, and mats, while also consuming its flowers. Within the plant’s trunk and roots lies a soapy substance rich in saponins, historically employed as soap and shampoo. And, the flowers of the genus Yucca are the state flowers of New Mexico!

These large spiny plants are actually members of the shrub family. A long-lived desert plant, Ocotillos (oh-koh-TEE-yohs) have been known to reach over 100 years old. Pollinated primarily by carpenter bees and hummingbirds, this giant shrub blooms spectacularly during desert rains. The origins of the name in fact mean “torch” in Nahuatl, the language of the Aztecs, most likely due to the brilliant orange and reds of the blooms.

Saguaros, the largest cacti in the United States, can reach over 200 years in age. Their accordion-like ribs store hundreds of gallons of water during rainfall, stretching their skin to accommodate more water, increasing their weight substantially. A fully hydrated saguaro can exceed a ton in weight. If you encounter a saguaro with drooping arms instead of upright ones, it likely experienced freezing temperatures for over 36 hours, causing tissue damage and weakening the connection between the arm and main stem.

Local lore tells a story that William Sturgis built a hacienda during Rancho de la Osa’s prosperous cattle operations in the late 19th century. Sturgis wed a woman named Doña Leonora. She ran a trading post catering to the Tohono O’odham people. The legends speculate that these structures, situated just beyond tribal boundaries, are remnants of her trading post and a stage stop. [Rancho de la Osa]

This gate signifies the transition onto reservation lands of the Tohono O’odham Nation, comprising approximately 28,000 members in Southwestern Arizona. Please do not ride beyond the gate.

The O’odham historically occupied a vast region known as Papagueria, spanning from Sonora, Mexico, to Central Arizona, and from the Gulf of California to the San Pedro River. Since the early 18th century, their land was subject to foreign rule, first by Mexico and then divided by the Gadsden Purchase of 1853 between the United States and Mexico. Despite promises by the United States to honor land rights under the Gadsden Purchase, the influx of settlers, mining, and railroad development led to the gradual loss of O’odham land.

Today, approximately nine O’odham communities in Mexico lie proximate to the southern edge of the Tohono O’odham Nation. Prior to 2020 and the building of the border wall the O’odham people were able to freely travel their lands.

As you exit the ruins, examine the creek bed closely, you will notice several check dams. These structures have been constructed to manage erosion and to capture or decelerate the water’s movement during intense rainfall. This strategy encourages the growth of vegetation, which not only aids in further slowing and dispersing the flow of water during rainstorms but also contributes to the creation of more habitats for wildlife, provides feed for livestock, enhances erosion control, increases organic matter and soil fertility, and offers shade, cooling, and shelter for the high desert environment.

Desert mistletoe has a native habitat spanning from the deserts of southern Nevada and California to central Baja California and southern Sonora in Mexico. Characterized by dense clusters of brittle stems, desert mistletoe relies on its host, typically mesquite, ironwood, and paloverde trees, for up to 80% of its carbon and all of its water and nutrients. Yet, being a parasite does not mean a species is lacking in positive qualities. It provides a crucial resource for Sonoran fauna in the fall and winter, particularly for the phainopepla, a crested black bird adapted to eating mistletoe berries.

At this mile mark, as you cross a wash, to your right is a distinct example of mistletoe hosting on an Ironwood tree.

At an elevation of 7,730 feet, Baboquivari Peak holds profound significance for the Tohono O’odham people as their most sacred site. It serves as the focal point of their cosmology and is believed to be the dwelling place of their creator, I’itoi. According to tribal legend, I’itoi resides within a cave located beneath the mountain’s base.