Depending on who you ask, the wild horses of the Devil’s Garden Plateau, in the northeastern corner of California, are a magnificent part of the state’s natural heritage or an invasive blight on a fragile landscape.

“These are living symbols of the historical pioneering spirit of the west,” said Suzanne Roy, campaign director for the American Wild Horse Campaign. “They’re living icons, symbols of freedom.”

According to the U.S. Forest Service, however, they’re also a pest.

This week, the Forest Service began a roundup of 1,000 mustangs in the 470 square-mile Devil’s Garden region of the Modoc National Forest, which is a designated wild horse territory. Wild horse advocates fear that hundreds of these horses could end up in Mexican and Canadian slaughterhouses.

The roundup, or, in the language of the Forest Service, the “gather,” involves buzzing the landscape with helicopters to flush bands of terrified mustangs out of the trees, corralling them together, and pushing them into the wide end of a funnel-shaped enclosure. There, a wrangler sends a trained “Judas horse” galloping down the enclosure, leading the other horses in a stampede down to the narrow end of the funnel as the gates are locked behind them.

Once they’re trapped in the pen, the stallions are separated from the mares, and the mares from their foals. That moment, said Roy, is “the end of their family and their freedom.”

According to the Forest Service’s plan for reducing the mustang population, the younger captured horses will be put up for adoption. Horses older than 10 years will be put up for adoption and for sale. For a period of 30 days, these older animals, expected to number about 300, will be sold to buyers who are prohibited from selling them off for slaughter.

After that period however, the remaining senior mustangs will be sold for $1 each, up to 36 a week per buyer, “without limitations” — meaning that they can be sold to buyers who may transport the horses to Mexico or Canada and sell them to slaughterhouses. The last horse slaughterhouse in the United States closed in 2007.

Opposition to horse slaughter in the United States is overwhelming. For years, Congress has prohibited the Bureau of Land Management, which manages the vast majority of public lands serving as wild horse habitat in the United States, from selling mustangs to buyers who will in turn resell them for slaughter. The prohibition has been routinely included as a rider in Congress’s annual appropriations for the Interior Department, which includes the BLM.

The Forest Service, however, is part of the Agriculture Department, which is subject to no such restriction. Under previous administrations, the Forest Service has abided by the prohibition anyway, recognizing that Congress intended to ban the sale of mustangs for slaughter generally, not just by the BLM. Under the Trump administration, which has proposed eliminating the rider in next year’s budget, that pattern has begun to change.

Unlike most mustang territories, the Devil’s Garden is mostly managed by the Forest Service, with only a small portion managed by the BLM. As the lead agency there, the Forest Service has not been willing to bar sales of senior horses to buyers who intend to resell them for slaughter.

“We would love to adopt all these horses out,” said Amanda McAdams, the Forest Supervisor for the region. “These are really pretty marketable horses — strong and sturdy.” But, she continued, “as a last resort, we’re considering selling horses without limitations.”

By sending wild horses into the slaughter pipeline, the Forest Service hopes to avoid expenses the BLM incurs by caring for mustangs removed from the range, but not placed in private adoption. According to the BLM, these costs account for two-thirds of its Wild Horse and Burro Program budget.

“What we’re really dealing with is managing the taxpayer money in a fiscally responsible way,” said McAdams. “Selling without limitations keeps us from putting them in long-term storage where we’ll be paying for them for the rest of their lives.”

At the same time, selling horses for slaughter will allow the Forest Service to rapidly depopulate the landscape, allowing it to rebound from impacts that the agency attributes to the horses’ overuse.