Rare sheep are U.S.-Mexico border crossers, but they’re hitting a sharp new obstacle

JACUMBA WILDERNESS, Calif. — On a dirt road in Imperial County leading toward the Mexico border, the tracks of rare wild sheep press into dusty tire tracks, amid jumbled boulders and spindly ocotillo. The white trucks and SUVs of the U.S. Border Patrol appear like ghosts in the desert.

Here, in the Jacumba Wilderness, people are halted at the border by federal agents, but Peninsular bighorn sheep have long migrated back and forth. The ewes give birth on the U.S. side in the winter and spring, then cross into Mexico to seek water in the punishing summer.

But some say they’ll be blocked this year. Recently, something new appeared on the landscape, alarming wildlife advocates like Christina Aiello. It glitters from a distance: Where the 30-foot steel border fence ends, great spirals of razor wire extend up craggy mountain slopes on either side.

The border wall is reflected in wildlife biologist Christina Aiello’s sunglasses.

U.S. Customs and Border Protection had announced plans to finish sealing off all 140 miles of the California-Mexico border, including in this remote wilderness.

“It will light a fire under us,” said Aiello, of the Wildlands Network, a conservation nonprofit.

Advocates like Aiello are now racing to secure measures to avoid catastrophe before the frontier is closed.

They want to install water sources for sheep stranded on the U.S. side. Without it, “you will see piles of dead sheep,” said Aiello, who is a wildlife biologist.

• Share via Close extra sharing options

Their effort seems to be paying off — to an extent. Border officials are tentatively signaling support for watering holes for bighorn, as well as the installation of small passages in the wall for wildlife, and floodgates to be left open during storms, according to Aiello, who is working closely with the California Department of Fish and Wildlife.

Jen Benedet, the state wildlife department’s acting deputy director for public affairs, said the agency is advising Customs and Border Protection on wildlife issues but is not trying to get it to agree to or fund any accommodations. Instead, wildlife agencies are “moving forward independently with immediate actions” to protect the sheep using money unrelated to the border wall.

There are already signs that the bladed wire is an obstacle for the animals. Aiello, looking at data from a GPS collar on a computer screen, saw a bighorn on the Mexico side walking in a straight line, as if along something, appearing to try to cross. But it was in a section of the border where there is no fence. It then turned around and headed back south. That was in mid-December.

Christina Aiello, left, and retired state biologist Janene Colby gaze up at razor wire that was recently installed in Peninsular bighorn sheep habitat.

So on a recent warm, sunny day, she hiked miles into the remote desert to confirm her suspicion — that razor wire now filled what not long ago was open terrain. She saw it gleaming as she trudged along a paved road that hugs the fence, dropping her hiking poles the moment it registered.

“This is a little frightening,” she said.

A spokesperson for Customs and Border Protection said it will place physical barriers “along all areas deemed necessary to ensure operational control of the border” but is “committed to environmental stewardship” while meeting operational requirements.

U.S. Border Patrol official Gregory Bovino, who, at least until recently was the face of President Trump’s deportation push, has a fondness for the sheep and has advocated adding a watering hole for them in the past, according to emails obtained by The Times.

Before he rose to national prominence, Bovino, as chief of Border Patrol’s El Centro sector, oversaw the small stretch of the border the sheep inhabit. Now, according to reports, he’s returning.

A trio of female bighorn sheep scamper among spindly, green ocotillo in Skull Valley.

“The guzzler is something Chief Bovino wants, because he has an affinity for the Big Horn Sheep and wants to see them prosper,” a watch commander for the El Centro sector said in an email in 2023.

Bovino once penned a thesis on what he described as the threat of illegal immigration to the hardy ungulates, according to the Chicago Sun-Times.

Conservation groups say the measures are welcome, but not sufficient — that bighorn, and other animals, will still suffer. They’re also calling on the state to advocate more forcefully for wildlife, and wonder whether political concerns are holding officials back.

The proposed openings in the wall, about the size of a piece of paper, would provide passage for animals like bobcats, badgers and even female mountain lions and their young.

But bighorn — with their broad, curved horns — can’t squeeze through. Neither can male mountain lions or mule deer, both of which inhabit this dramatic desert.

Janene Colby, who monitored Peninsular bighorn in the Jacumba Wilderness for more than a decade, said the razor wire is “much more dangerous for them than a fence.”

Wildlife advocates asked for larger openings or to leave some of the border unfenced, but that was denied, according to Aiello.

Scientists and conservationists say the larger species will be cut off from food, water and mates with precious genetic diversity. Those that live along the border could die, and, in the long run, populations may be more susceptible to disease and climate change.

The bighorn herd that straddles the frontier will be severed. Those trapped south of the border won’t be able to get to their nursery grounds, while those to the north will be cut off from their hydration spot.

Scientists expect sheep stuck in the U.S. will head toward Interstate 8 in search of food and water, increasing the risk of collisions.

Similar scenarios are playing out across the Southwest, where the 1,954-mile border cuts through the habitat of more than 80 threatened and endangered species — from ocelots in Texas to Mexican gray wolves in New Mexico and Arizona, according to the Sierra Club.

Trump has vowed to complete the border wall during his second term, and provided a lot of money for it. Congress approved more than $46 billion for wall construction as part of the One Big Beautiful Bill Act.

The 30-foot border fence stretches across the U.S.-Mexico border in the Jacumba Wilderness.

The secretary of Homeland Security has also waived applicable environmental laws for border projects, a power granted in the Real ID Act of 2005. That means laws like the Endangered Species Act, National Environmental Policy Act and Clean Water Act don’t apply.

The razor wire is part of the approach. Starting in the fall, federal forces began installing hundreds of miles of it along the border.

It’s “part of a necessary, strategic effort to bolster this security by discouraging and preventing illicit movement across this border,” according to a spokesperson for the Joint Task Force-Southern Border, which provides military support to border operations.

In October, Eamon Harrity, wildlife program manager for Sky Island Alliance, ventured into critical jaguar habitat in Arizona’s Coronado National Memorial. He was checking cameras installed by his conservation group in the steep, rugged terrain to monitor how the border fence is affecting animals.

There was a low rumble that vibrated for a second or two, then faded away. It was dynamite — a sign that barrier construction that began in 2020 but was never finished had restarted, he said.

“I could feel and hear this kind of dramatic change coming,” he said. “It makes you feel like crying.”

On Nov. 2, Edie Harmon, who lives down the road from the Jacumba Wilderness, learned Marines were stringing wire up a mountain in what’s called Skull Valley. It was mid-afternoon and the 81-year-old arrived as the Marines were leaving.

A local resident, Edie Harmon, right, first documented the concertina wire strung over the rugged landscape in November and said activity ramped up in early January.

North-facing slopes of the mountain were cloaked in shade, and “it was possible to see concertina wire from a great distance if one knows where to look,” Harmon wrote in a report — part of ongoing documentation of activity at the border that she started in 2020.

Harmon frequently treks through the desert, wearing ankle braces and an orange safety vest, chatting with Border Patrol agents who appear to have taken to her. Recently, one gave her a patch that says, “Protected by U.S. Border Patrol.”

She deeply admires the work of Janene Colby, the former Peninsular bighorn biologist for the state Department of Fish and Wildlife, and she knew the area recently draped with razor wire was where the sheep give birth. She conveyed her concerns to the Marines hauling it up the steep slope and alerted a number of stakeholders, including Colby.

Colby helped get razor wire there removed once, before she retired about a year and a half ago.

“Sheep and other ungulates, like deer, can get caught in razor wire, especially lambs,” Colby said. “So it’s much more dangerous for them than a fence.”

Military officials say the wire being used has properties that reduce such risks.

The spokesperson for the Joint Task Force said that its “large, spring-like coils” form “a thick ‘3D wall,’” and its bulkiness makes it easier for people and animals to see.

“This high visibility acts as a better deterrent for people and helps prevent animals from accidentally running into the wire or misjudging a jump,” the spokesperson said in a statement. “Additionally, because concertina coils are rigid and stay under tension, they don’t ‘sag’ or create the loose, invisible snares that single-strand wires often do over time, which helps reduce the risk of accidental wildlife entanglement.”

On a warm, January day, Janene Colby hikes near concertina wire in the bighorn’s lambing grounds.

Two weeks ago, Colby gazed at the new wire for the first time. Not unlike a bighorn, she handily scrambled up the craggy slope it stretched over. “It’s kind of insane,” she said.

“We just keep throwing all types of barriers out in front of them, and we make it harder and harder for them to survive in their environment with what little they have left,” she said.

In the summer of 2020, when a segment of the wall was being built in the Jacumba Wilderness, Colby recalled getting a call about a sick lamb. It was severely dehydrated and sluggish.

Colby believes that, due to the construction activity, it was separated from its group as they crossed into Mexico. She gave it water and hoped it would link up with other sheep migrating to their water source. At 4 or 5 months old, it wouldn’t know where to go.

A few months later, a dead lamb was discovered near a service road. It appeared to be the same one — and to have died of thirst, she said.

As the border fence rises, some say California state officials should be leading the charge on protecting local wildlife — and so far have not.

Several groups — led by Dan Silver of the Endangered Habitats League — called it “a grave situation” in a December letter to the heads of the state Natural Resources Agency, Department of Fish and Wildlife and Department of Forestry and Fire Protection. They beseeched the leaders to “take all possible steps to maintain wildlife movement across the international border.”

Colby, the retired state Department of Fish and Wildlife biologist, said her former agency is committed to protecting bighorn, which is why she’s sorry they have not been cleared to advocate on behalf of the sheep with border officials.

A female bighorn, or ewe, walks in the rugged terrain of the Jacumba Wilderness.

She thinks the Natural Resources Agency or Fish and Game Commission may be blocking the agency, afraid that if it speaks out against the Trump administration’s plans to close the gaps in the border fence, they may lose federal funding for wildlife projects.

In a statement, an official with the Department of Fish and Wildlife said the agency is dedicated to the recovery of the sheep, including those that migrate cross-border.

It has had discussions with the U.S. Fish and Wildlife Service about the impact of barrier construction on protected species and habitat and has “received photos from concerned citizens showing grading, clearing, habitat destruction and installation of concertina wire and new barrier wall in remote areas,” including wildlife corridors used by Peninsular bighorn, according to the official, who said the agency continues to monitor the activities.

In a statement, Daniel Villaseñor, a spokesperson for the Natural Resources Agency, said the state “has been deeply engaged” in supporting wildlife in the border region while balancing the needs of nearby communities.

Both agencies declined requests for an interview.

Resistance to barrier construction along the border has cropped up in other corners. In early January, the city of San Diego sued the federal government over razor wire placed on its land, saying it constitutes trespassing and disturbs sensitive habitat.

Today, bighorn eke out an existence among the russet-tinged barrel cacti, which they sometimes turn to for water in the harsh desert.

Last month, as the sky faded to cotton candy pink, Colby spotted nearly a dozen sheep scaling the side of a mountain. With the naked eye, they looked like sand-colored specks. But looking through her spotting scope, they appeared in high definition. One ram appeared to pose in the golden-hour light, a shadow of his curled horn cast on his cheek.