FEATURE | By Chuck Graham

Ghost Herd Returns: Once Feared Vanished, Sespe Bighorns Thriving

A shard of crumbling shale skittered down the cliff, drawing my gaze upward into the blue skies above the rugged Sespe Wilderness, part of the Los Padres National Forest.

A majestic desert bighorn ram picked its way toward me with nimble grace, making me forget I was clinging to a precarious three-foot-wide ledge. Its steady gaze held mine, bold and unflinching, as it approached to within 25 feet.

But hunger called the broad-shouldered ram. It quickly lost interest in me and shifted focus to munching birchleaf mountain mahogany, hollyleaf cherry, and spiny rush — a rugged buffet for these agile herbivores.

Soon, he joined 13 other bighorn sheep — clearly his herd. One other smaller ram lingered nearby, but the rest were ewes. Between feedings, the dominant ram sniffed each female to check for estrus. It was a moment of wilderness peace — until it shattered. A rocket launch from Vandenberg Air Force Base ripped through the Sespe with a thunderous shockwave, spooking the herd into a full sprint.

As disruptive as the sonic boom was to all things wild in the Sespe, the sheep’s response was breathtaking. They vaulted skyward in two astonishing bounds. Clearly, height and open terrain were their edge against danger.

Sespe Survival

For over 100 years, desert bighorn sheep had vanished from the Sespe. Hunting, livestock-borne disease, and shrinking habitat wiped out the iconic desert dwellers by the late 1800s.

But in 1985 and again in 1987, California Fish and Game conducted two bighorn transplants totaling 36 animals. The sheep came from Cattle Canyon in the San Gabriel Mountains — about 60 miles southeast as the condor flies. The Sespe has always marked the western fringe of their historic range. The translocated sheep were released near the southern slopes of San Rafael Peak at 6,634 feet and near Mutau Flat.

Although the release began with promise — 28 sheep fitted with VHF radio collars — the outcome proved grim. Fierce winds scattered the fragile herds far from escape terrain like the sparsely vegetated San Rafael Peak. By 1989, 16 bighorns were found dead, likely taken by mountain lions.

“Monitoring efforts for this population were extremely difficult in the 1990s and early 2000s, with a small population in highly inaccessible terrain,” said Dustin Pearce, an environmental scientist with California Fish and Wildlife, who is the unit biologist in Santa Barbara and Ventura Counties covering the Sespe bighorn sheep population. “By 2003, the population was considered extremely reduced/extirpated.”

Then came the Day Fire of September 2006. The blaze consumed 160,000 acres, sweeping through the chaparral-choked Sespe Wilderness. However, it proved crucial for the Sespe bighorn’s survival. These animals rely heavily on keen eyesight to spot apex predators — mainly mountain lions.

When the translocations occurred in the 1980s, the terrain around San Rafael Peak was so overgrown that predators had the upper hand over unwary bighorn. But the Day Fire reset the balance between prey and predator. With the chaparral cleared, the desert bighorn population began to rebound. It also gave hikers and backpackers wandering the Sespe a rare chance to spot these nimble animals navigating steep cliffs and narrow canyons in their newly opened habitat.

As sightings increased, survey efforts were renewed with an intensive collaring operation in 2017. Nineteen animals were fitted with radio collars, yielding fresh insight into their range and behavior. By 2019, the population was estimated at 119 animals, with a confidence range between 88 and 150.

There’s growing optimism that these desert bighorn will continue expanding their territory throughout the Sespe. Unconfirmed reports place them near Thorn Point, several miles west of San Rafael Peak, with confirmed sightings as far east as McDonald Peak at 6,870 feet.

Confirmed Sighting

They were resting on a steep, grassy slope on a nameless potrero between San Rafael Peak and the narrow spine of Johnson Ridge. Ten desert bighorn sheep, all facing eastward, were spotted by one of the ten guides I work with at Channel Islands National Park. A couple of us had binoculars, and that’s when Jerry blurted out, “There’s some bighorn right there,” pointing.

We all gazed at the same sweeping slope, awestruck by the sight. They were at least a mile away, and about four miles north of the Sespe River.

The ram perched above the group, no doubt watching over his herd, which included two lambs — a promising sign that their numbers continue to grow. As we descended the rolling spine of Johnson Ridge, we kept tabs on the sheep as they basked in mid-winter sun and 60-degree air. During our final rest stop on an exposed ridge, we watched the band stretch and amble into a narrow ravine plunging hundreds of feet toward a shaded creek. They vanished into the dense chaparral, their tawny coats blending seamlessly with the tangled wild.

following grinnell’s trail

Not long after photographing desert bighorn sheep in the Sespe Wilderness in December 2024, I gave a presentation on the Carrizo Plain National Monument to the Santa Ynez Valley Natural History Association. Before the talk, I had dinner with board member Page Philler-Adams, my girlfriend and all-world naturalist Holly Lohuis, and Dr. Paul Collins, retired curator of vertebrate zoology at the Santa Barbara Museum of Natural History.

Dr. Collins asked what I’d been working on, and I told him I’d just returned from the Sespe, photographing those stealthy, nimble creatures. Then he asked if I’d heard of Dr. Joseph Grinnell. I said I had, and mentioned I’d heard there were once desert bighorn sheep in the Caliente Mountains — overlooking the Carrizo Plain to the northeast and the starkly beautiful Cuyama Valley to the southwest.

“Look him up at the Museum of Vertebrate Zoology at UC Berkeley,” said Dr. Collins. “Grinnell did an extensive study of wildlife surveys in California in the early 1900s.”

sweeping surveys

After several emails and phone calls, I finally reached Chris Conroy, curator of the Museum of Vertebrate Zoology (MVZ) at UC Berkeley. He sent me a digital copy of Grinnell’s journal from his 1912 expedition documenting California wildlife.

Spotting wildlife isn’t easy. It’s a waiting game. Hours in the field hoping something materializes. Searching for burrows, dens, nests, scat, and spoor. It requires patience. Grinnell was doing all of that — and more — logging discoveries across countless habitats. He traveled far and wide across the most biodiverse state in the Lower 48, monitoring and counting species by car, train, horseback and on foot. He never found bighorn in the Sespe, but that didn’t stop him from looking throughout California’s vast desert terrain.

In one journal entry, Grinnell recounted speaking with ranchers on the southwest side of the Caliente Mountains in the Cuyama Valley. Their ranches, nestled at the base of the arid range, were near where they’d occasionally seen desert bighorn. They believed the animals had since been hunted out. Still, Grinnell went to investigate. On April 26, 1912, he didn’t see any bighorn — but on a north-facing slope, he discovered a lone, weathered horn. It became one of many specimens he brought back to the Museum of Vertebrate Zoology.

The Caliente Mountains remain one of California’s most remote regions, devoid of human settlement. The range is arid, blanketed in juniper groves and scrubby chaparral. Several times a year, it gets snow. The summit — at 5,106 feet — is the highest point in San Luis Obispo County. A collapsed cabin at the peak once served as a lookout during World War II.

getting my jurassic on

Conroy invited me to photograph the single horn left long ago by that ram, and I took him up on it. When I arrived at the MVZ, I felt like I’d stepped into the original Jurassic Park. We climbed a spiral staircase into the museum’s inner sanctum, passing above the towering skeleton of a Tyrannosaurus rex.

After photographing the horn, I headed straight for the Carrizo Plain, specifically the northeast foothills of the Calientes. I followed Bitterwater Valley Road, a windy two-lane that connected with Highway 58, then down Soda Lake Road, the monument’s main artery. I car-camped on a nameless dirt track. Staring up at shooting stars, I imagined desert bighorn sheep once again traversing the rolling Caliente Mountains.

The California Department of Fish and Wildlife maintains a current map of bighorn sheep populations across the state. Most of the occupied habitats are in the desert, but the Sespe and San Gabriel Mountains still harbor growing herds — where rugged isolation has aided their survival.

Several red-outlined areas mark unoccupied habitats, including the Caliente Mountains. Long-range conservation plans are underway to one day return bighorn to these ancestral ranges.

Good things in life can sometimes take a long time.