From Ranch to Refuge
Some History: "Buenos Aires" means "good air" in Spanish. This was a name given by one of the original Altar Valley inhabitants - Pedro Aguirre. Altar Valley was a tree-less, open plain filled with knee-high, lush grass as far as the eye could see. Pedro was from a prominent family in Sonora, Mexico and somewhat of an entrepreneur. He established a stagecoach line through the Altar Valley in the 1850's and in 1864 established the Buenos Aires Ranching Company for cattle and sheep. He dammed the local washes establishing Aguire Lake, which remains a seasonal wetland to this day.
As ranching boomed in Altar Valley, sightings of native species such as Mexican wolves, black bears, jaguars, aplomado falcons, pronghorns, masked bobwhite quail, and Chiricahua leopard frogs began to dwindle. The 7 year drought from 1885- 1892 proved most devastating to Altar Valley as 2/3rds of the cattle herds lay dead on the range. The remaining 1/3rd consumed the remaining vegetation, stripping the land bare. With the land bare, the wildfires disappeared. When the rains returned and with no grasses to hold the moisture, deep washes and gullies formed for the first time to forever change the landscape. These events allowed mesquite trees to invade the valley to further disrupt the grassland ecosystem.
As Altar Valley slowly recovered from the devastating 7 year drought, ranching continued. Between 1909 and 1985, five different ranching families owned Buenos Aires Ranch. In 1985 when Buenos Aires Ranch was offered up for sale, the U.S. Fish and Wildlife Service acquired the property along with some adjacent ranches to establish the Buenos Aires National Wildlife Refuge with the expressed purpose of restoring the grasslands and bringing back native pronghorns and masked bobwhite quails from the brink of extinction.
The Hike: Having traveled about 20 miles south along Hwy 286 from Hwy 86 and Three Points (Robles Junction), you will come to the Buenos Aires National Wildlife Refuge boundary. We'd spotted our first pronghorn as it emerged from the side of the road about 5 miles north of the Refuge boundary. The Baboquivari Mountains form a spine currently dominating our view to the west. A few miles earlier, the sun glazed brilliantly off the observatories on Kitt Peak. Almost immediately as you enter the Refuge, you are greeted with expansive views of open grasslands punctuated with mesquite trees.
You will notice a series of unmaintained dirt roads radiating from Hwy 286. Access permits are not required, just open and close the gates and explore at will. Dogs on a leash are allowed. We chose a couple of these side roads to explore while keeping Skippy on his leash. In the back of my mind I'm thinking that these roads would be perfect to explore using a mountain bike...
The summer monsoons have turned Altar Valley a brilliant green. Even the slopes of Baboquivari are green. Isolated barrel cactiare in bloom throughout the grassy plain. As we walk along the westerly dirt road, a raptor perched atop a mesquite tree comes into view. Simultaneously we notice a coyote in the grass headed towards us! Stunned by the cornucopia of wildlife we accidently reveal our presence causing both animals to scurry off. Luckily I had the long lens on the camera and snapped off a couple of in-flight images. Later, as we walk along the easterly dirt road, massive yellow patches of Arizona Caltrops Arizona Caltrops are found in the lower grounds. I believe this is the first time I've ever seen these wildflowers...
We continue our trek south along Hwy 286 towards the Buenos Aires Ranch and Visitor Center spotting the entrance road with obvious signage. We stop at the water-filled ponds along the entrance road hoping to catch a glimpse of a heron, egret, or other long-legged water bird. No luck today...
As warned by Bonnie Swarbrick from the Fish and Wildlife Service in an email exchange earlier in the week, the Visitor Center is closed this weekend and devoid of any other humans. The Visitor Center is staffed by volunteers on the weekends and hours are dictated by their availability. Information pamphlets, maps, and restrooms are still available whether or not the Visitor Center is open.
Buenos Aires Ranch has a signed hiking trail that traverses the grounds. Check out the old ranch house, barn, corrals, and stock pens. Remember that this was a working ranch until 1985. We continue along the Sonoran Desert Grassland Trail to Aguirre Lake. No long-legged water bird sightings here either...
Pronghorn Drive was next on the activity list. This is a 10 mile loop drive through the fawning grounds and reportedly the best wildlife spotting opportunity. The drive is excessively washboard testing the suspension of my F-150. We make frequent stops to scan the horizon with binoculars looking for the elusive pronghorns. Still no luck, but impressive scenery certainly compensates. As we dip into a wash I notice a moving rock - it's a desert tortoise! Continuing along Pronghorn Drive we stop at a ridgeline section offering 360 degree views of Altar Valley.
Trying to be patient, I start to read some of the pamphlets we collected at the Visitor Center. One pamphlet indicates that "Everyday is the best day to visit Buenos Aires NWR" and proceeds to countdown the months of the year and associated natural events at the Refuge. "August - Caltrops (summer poppies) carpet areas burned earlier this year. The grasslands turn to a lush green carpet from the summer rains." OK, I'll agree with those observations. "September - Horse Lubbers , those huge black grasshoppers with small green-veined wings, are everywhere." OK, I'll certainly agree with those observations as well!
I grab another pamphlet to read. This one indicates that pronghorns were reintroduced to the Refuge in 1987 and that the current population number is 60. OK, 60 animals in a 118,000 acre Refuge, that's 1 pronghorn every 1967 acres. Let's see, there's 640 acres in a square mile so that's 1 pronghorn every 3 square miles. I think my patience just ran out...
There are 3 developed trails off of Arivaca Road. The Arivaca Creek trail head is located at 31o 35.669'N, 111o 21.815'W. This is a 1 mile loop trail that leads to the stream edge. Despite the summer monsoons the stream had no flowing water or pools today. Copious sunflowers could be found along the stream banks. If you continue downstream (head west) about 1/4 mile, you will notice another trail climbing the surrounding hillside. This is the Mustang Trail, a 5 mile in-and-out trail that scales the south ridgeline.
A brief downpour pushes us back to our vehicle and we soon come to the small town of Arivaca. This is listed as a ghost town in some literature, but I can report that amongst the abandoned buildings (and cows) are a couple of bars and restaurants. The Arivaca Cienega trail head is located on the east side of Aricava at 31o 34.558'N, 111o 19.402'W. This is a 2 mile loop that includes a boardwalk over Willow Pond. Comprised of 7 springs, this lush cienega has abundant wildlife including some incredibly large spiders with equally large webs.
Summary: This is a great introductory hike to the Buenos Aires National Wildlife Refuge with a variety of grassland and riparian flora and fauna. It is a migratory birding hotspot and a "poster child" for modern day conservation efforts bringing back several native species from the brink of extinction. It is a unique ecosystem that will leave you wondering - Is this Arizona? Enjoy!
Check out the Official Route and Triplogs.