Controlling livestock in Big Bend National Park means rethinking the culture of ranger work
By Margret Grebowicz
The Sierra Club Magazine
Visitors to national parks may expect to see lots of animals. The most exciting to encounter are usually the most charismatic — moose, elk, grizzly bears, alligators, condors. But visitors to Big Bend National Park in Texas have been experiencing something different — cows and horses. They come from the small ranches on the Mexican side of the Rio Grande, walking across the river to graze on the lush grass on the U.S. side, which is under strict environmental protection. Sometimes, the livestock remain on the U.S. side, eating the park’s vegetation, until their owners round them up to return home.
Big Bend is not the only national park in the country where livestock occasionally graze illegally. But according to Raymond Skiles, who retired after nearly 30 years as the park’s wildlife biologist and wilderness coordinator, Big Bend is the only park where ranchers deliberately graze their livestock. Skiles is one of 23 former retirees who coauthored a letter to the National Park Service regional director in November 2023, outlining the damage caused by these trespassing livestock.
The letter states, “Trespass livestock trample vegetation along hundreds of repeat travel routes. They cause vast areas of erosion by destroying protective soil texture and crusts. They annually consume tons of native vegetation. Their soil and vegetation disturbance fosters non-native plant invasion. The animals have destabilized historic structures and have trampled and tilled numerous archeological sites.”
The Coalition to Protect America’s National Parks, made up of largely Park Service retirees, wrote a similar letter in 2024, stating that Big Bend is “the most severe trespass livestock situation in the US national park system.”
Skiles helped put together Big Bend’s Trespass Livestock Management Plan and authored an environmental assessment in 2018. It was the first time the park drew up a comprehensive assessment of the livestock issue that met the requirements of the National Environmental Policy Act (NEPA). He also oversaw surveying work and coordinated reports by private contractors and university researchers who could quantify the damage.
At that time, his team counted roughly 300 cattle and horses illegally grazing in the park daily. According to Skiles, park officials declared the number unacceptable and aimed to reduce the population by at least two-thirds, to 100 animals or fewer. But just as the management plan was approved, during a period between full-time superintendents, the park abandoned the program. In 2022, researchers counted over 500 animals during a fixed-wing aerial survey. Another count in 2023 noted 365.
“Last year’s fixed-wing survey picked up 917 animals. … The standard correction factor is that a fixed-wing survey will find about 50 percent of the animals,” Skiles said. “Given that correction factor, there may now be as many as 2000, possibly more, livestock using the park at any one time.”
Round them up
Valerie Naylor was chief of interpretation and visitor services at Big Bend in the 1990s. In those days, she said, the livestock was a threat to park ecology, but she didn’t see it as diminishing visitor experience until she started returning to the park regularly as a tourist. “It’s not unusual to see several groups of cattle walking through the campground — herds, not one or two stragglers. There are cow pies all over the place, all the time, around the Daniels Ranch picnic tables. I have seen people photographing cows and horses,” Naylor said. “It’s just weird.”
Marcos Paredes, another retiree who signed the November 2023 letter, lives seven miles north of the park’s western boundary, and he regularly finds trespass livestock grazing on his land. He coordinated the roundups of trespassing animals for over 20 years. After he retired, the trespass livestock coordinator role was discontinued, and all the ranger horses, used for livestock gathering and patrol, were sold. In the absence of ongoing roundups, the situation can only get worse, Paredes said. The issue is not just economic, but cultural.
“As long as there’s no pressure for the owners to round them up, they won’t,” Paredes said. “But raising livestock is not a sustainable way of life there — it takes more land than the cattle can support. The land on the other side of the river is already overgrazed.”
In the past, park officials have stated that the old management techniques were largely ineffective, but Paredes said the opposite is true. He joined the Park Service because he liked working outdoors with animals. Managing trespass livestock was a rewarding job with good results — as long as there were regular roundups, the numbers stayed low. But with every year, the park employed fewer staff who were familiar with or comfortable around livestock.
“Very few folks are doing the kind of ranger work I was doing when I came on,” Paredes said. “The park needs to bring back wranglers, people who know how to work with livestock, people who understand low-impact techniques for rounding up cattle — not your typical park ranger.”
For as long as Skiles can remember, livestock control had been the job of law enforcement rangers. He said professionalization changed the park’s work culture. “Before I got started in the Park Service, a ranger was expected to do lots of things, ranging from fixing up trails to cleaning toilets,” Skiles said. “When ranger positions became much more uniform from one park to the next, it was inevitable that someone was going to say that livestock control doesn’t meet the national standards for what rangers do.”
For several years in the early 2000s, Whit Hibbard worked as a wrangler in Big Bend. A fourth-generation Montana rancher, Hibbard also worked in several other national parks in the U.S. and Canada, including Yellowstone, developing low-stress handling techniques for bison reintroduction programs and wild horse management. Skiles called him “the best round-up guy there ever was.”
In 2005-06, Hibbard designed and implemented a low-stress livestock capture project in the park — an animal-centered approach based on communication instead of fear and coercion. “By the end of that winter, we had rounded up every animal, as confirmed by a ranger pilot flying and rangers on the ground. And we never got our horses out of a walk.”
Hibbard left Big Bend when the culture of the Park Service started to change. “I very much wanted to stay on, but there was a shift in the service.” He refused to return on an as-needed basis because he believes the only solution is to create a district ranger-level trespass livestock coordinator position — a new, permanent position that, within the National Park Service, only Big Bend would have.
A long-term issue
With Trump proposing the largest budget cut in National Park Service history for 2026, this is an especially sensitive time to ask for the creation of a bespoke ranger position. According to Naylor, however, the budget isn’t the biggest obstacle.
“Parks are always underfunded, but it’s a matter of priorities. This is a long-term issue. If they don’t return to keeping it at bay now, it’s going to be even worse later.”
Rob Arnberger was Big Bend’s superintendent in the early ’90s and went on to be superintendent of Grand Canyon National Park and then Alaska regional director. He also signed the November 2023 letter and sees the issue as a glaring example of how much federal-level support the entire park system needs right now.
“National parks are falling behind in meeting their legal requirements and commitments,” Arnberger said. “Staffing and support budgets are well short of what is needed to care for these special places and have been for years. The trespass livestock issue in Big Bend continues to be neglected in the face of further cuts, firings, budget cuts, and political shenanigans.”
For Paredes, this means that maybe the National Park Service is no longer a reliable protector of land. His own property abuts 6,100 acres currently in the care of Big Bend Conservancy, which was donated to the national park. But last January, a bill that would have authorized the transfer failed to pass. The conservancy continues to hold it in trust. Many people are upset that the bill didn’t pass, but Paredes is only concerned about the land itself.
“Ten years ago, I would have told you that NPS lands are untouchable, that that was the best place for land to be. In the last decade, I’ve learned how false that is. Every day, I think we’re one news cycle away from losing park land.”
Margret Grebowicz is Maxwell C. Weiner Distinguished Professor of the Humanities at Missouri University of Science and Technology. Her latest books are Rescue Me: On Dogs and Their Humans and Mountains and Desire: Capitalism vs. The End of the World. Her essays have appeared in the Atlantic, The New Yorker, Slate, and the New Republic.
The article was originally published by the Sierra Club Magazine on June 16, 2025.