The fatal entanglement is raising alarms among wildlife experts who say the concertina wire poses a threat to regional biodiversity.
On Wednesday, June 3, 2026, Wildlife biologist Christina Aiello found an endangered Peninsular bighorn sheep that had died after becoming entangled in concertina wire at the border in the Jacumba Wilderness.
U.S. Customs and Border Protection is closing gaps in the California-Mexico border with concertina wire. The Peninsular bighorn sheep’s heavy, curved horns and front legs were trapped in the bladed, large coils. Christina Aiello, a wildlife biologist at the Wildlands Network, found the ram last week in the Jacumba Wilderness, decomposing. This was the first death-by-border-wire Aiello had seen.
Residents in Jacumba and Boulevard said they have also observed more wildlife wandering near their homes, some of them with lacerations, since the federal government began sealing gaps in the California-Mexico border. Aiello said she wasn’t surprised by the ram’s death. For months, she and several other scientists and conservationists had been warning U.S. Customs and Border Protection officials about the consequences of wire fencing in natural areas.
Late last year, CBP began installing concertina wire in the Jacumba Wilderness where the animal was found. The addition of the coil fencing is part of the federal government’s largerto close the last remaining openings in the border wall, including in San Diego and Imperial counties, with “30-foot-high six-inch-squared diameter steel bollards” and a secondary barrier wherever possible, as well as surveillance cameras and LED lighting.
Aiello has asked CBP to remove the wire and to build animal passages on the steel U.S.-Mexico border wall that are large enough for bighorn sheep to cross. Those requests have been denied.
“If they have completed the razor wire fence, if they're doing construction on the border, you then have risks of that entanglement problem,” said Aiello. “If they leave that razor wire up, you have risks of death or interactions with construction vehicles. ” CBP declined to comment. A spokesperson deferred questions to the Joint Task Force – Southern Border, which did not respond.
In an emailed statement, the California Department of Fish and Wildlife confirmed the ram had died after getting caught in the large coils.
“CDFW has been clear with the federal government that border wall construction poses serious risks to protected wildlife, including bighorn sheep,” the statement added. “This is another tragic reminder of those concerns. ”On Wednesday, June 3, 2026, wildlife biologist Christina Aiello found an endangered Peninsular bighorn sheep that had died after becoming entangled in concertina wire at the border in the Jacumba Wilderness. U.S. Customs and Border Protection is closing gaps in the California-Mexico border with concertina wire.
Aiello was surprised to find the ram caught by the wire on a flat section of the Jacumba Wilderness, rather than high up in the remote area’s boulders.
“My thought here is that it actually might have just been grazing next to the fence, not even trying to jump over it,” she said. “Something as simple as just walking by with your head down and you're not paying attention, and a horn gets caught can create a very hazardous situation as the animal panics and starts to react.
” “If something so kind of mundane as walking next to the fence could lead to entrapment, I do think that the longer that fence is up, you know, the greater the risk,” Aiello added. In Boulevard, resident Karen Parker said she has noticed more mountain lions in her community. She recently found one with noticeable lacerations on its back legs.
“Big cats have lost their habitat ," she said. “ have always been out here, but not like this and not this many. I put water out for them and that’s all we can do.
” On Monday, Jacumba resident Tanya Wilkins Aiau reported the death of what she believes was a wild horse that had been struck by a vehicle on Old Highway 80 near Jacumba to San Diego County Public Works officials. She said she believes the new border wall construction is pushing the horses toward busy highways.
“Because of all of the disruption, they don’t have their regular spots anymore,” she said, adding that local residents have reported two other wild horse deaths in recent months. Aiello said she is working with state agencies and nonprofit organizations on both sides of the border to monitor wildlife movement using cameras and GPS trackers. They are also working on securing funding to install permanent water sources for animals who may lose their resources because of the border wall’s expansion.
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