Please Wait a Moment
X

Duel in the Desert

The Latest Feature Articles Duel in the Desert
Duel in the Desert: Aoudad Management Beyond Bighorns
By Chester Moore

There are far more aoudad (Barbary sheep) west of the Pecos River in Texas than there are desert bighorn sheep on the planet. With some estimates citing as high as 80,000 to 100,000 aoudad, the North African import has not only taken a foothold in the region but is in the process of displacing native wildlife along the way.

Aoudad on a mountainside in Texas

Two aoudad run along a rocky ridge of Guadalupe Mountains in Texas.

The most critically affected species is the desert bighorn sheep. In 2019, Texas' desert bighorn population had reached a historic high of between 1,200 and 1,500 animals, and it had remained disease-free for decades.  That changed when the respiratory pathogen Mycoplasma ovipneumoniae (Movi) struck a herd at Black Gap Wildlife Management Area and, over time, spread to other bighorn herds across the region. Unlike most Movi outbreaks, which are associated with contact between bighorns and domestic sheep or goats, this transmission came from aoudad. 

Within a short period, Texas lost more than half of its desert bighorn population, and the reality of disease spillover from aoudad could no longer be ignored.

"Aoudad complicate things for our desert bighorns in Texas in a major way, and the situation inspires us to do even more to conserve our Texas desert bighorn populations," said Dr. Sam Cunningham, Wild Sheep Foundation (WSF) board member and Texas Bighorn Society (TBS) President. "This led to restoring a disease-free desert bighorn herd to Franklin Mountains State Park in December 2024 and to deep research on the impact of aoudad in West Texas."
 

Desert bighorn ram being released in Texas

Ram 14 jumping from the trailer into the Franklin Mountains State Park. Courtesy Chester Moore.
Not Just Bighorns

A comprehensive study led by the Texas Parks and Wildlife Department (TPWD) in collaboration with Texas A&M University, Sul Ross State University, and Texas Tech University, as well as private landowners, reveals that the impact is not limited to bighorns.

A massive population of ungulates in a drought-prone high desert can cause severe habitat damage, and a rising concern is the effect on mule deer.

The TPWD report highlights stark contrasts in survival and range use. Mule deer bucks have median ranges of around 3,316 acres, while aoudad rams roam vast swaths of 18,515 acres. This wide-ranging behavior allows aoudad to exploit food and water resources far more efficiently than mule deer.

"Aoudad can really switch their diet preferences," said Shawn Gray, TPWD Mule Deer and Pronghorn Program Leader. "They can go from grass to browse and survive off what's available, especially during drought. Mule deer are browsers, so they lose out."

In recent captures, mule deer were in poor condition due to drought conditions, while aoudad were "fat and healthy," according to Gray. "It looked like the aoudad had been living on a fed ranch," he said.

In one aerial survey of the Chinati Mountains, biologists counted 7,881 aoudad, roughly one for every 40 acres, compared to just 508 mule deer. Even after an aerial gunning operation removed 5,773 aoudad there, the population rebounded to 3,420 within five months, primarily through prolific lambing.

"Aoudad ewes are baby-making machines," said Froylan Hernandez, TPWD's Desert Bighorn Sheep Program Leader. "They can have twins, breed twice a year, and start young and bighorn ewes which have a lamb a year can’t keep up with that.”

The desert these vast herds of aoudad live in doesn't recover quickly either. When aoudad inundate an area, particularly in dry years, it can take years for the land to bounce back. This loss of forage impacts desert bighorn, mule deer, and other species, including pronghorn, scaled quail, and javelina.

"Habitat degradation is the root of all these issues," Hernandez said. "And the drought only makes it worse. Without habitat recovery, none of our native species will thrive."

In the Chinati Mountains alone, TPWD estimates that removing those 5,773 aoudad saved 19.4 million pounds of forage in a single year.

Survivability

A compelling part of the story lies in the stark contrast between the annual survival rates of collared aoudad and mule deer in the same habitats.

Aoudad survival was remarkably high, with annual rates reaching 94.6 percent in the Chinati Mountains and 89.7 percent in the Quitman Mountains.

In contrast, mule deer fared far worse. Annual survival rates dropped as low as 57.5 percent in the Quitman Mountains, and even at their best, 72.6 percent in the Chinatis, they still lagged behind those of the aoudad.

One of the key mortality factors for mule deer was predation, particularly from mountain lions. In the Chinati Mountains alone, at least three collared mule deer were confirmed killed by mountain lions, with additional cases suspected but too degraded to confirm. Meanwhile, no aoudad were found to have been lost to predation in either study area.

This discrepancy in both survival rates and mortality causes illustrates how aoudad are not only outcompeting native species for food and space but are also less susceptible to natural pressures that are severely impacting mule deer.

Mule deer buck in velvet

Positive Moves

The studies and aerial gunning profiled here were all conducted on private land with full cooperation of TPWD.

"We're finally getting a lot more buy-in on the management of aoudad numbers," said Shawn Gray. "Landowners are starting to realize if they don't manage the population, aoudad are going to dominate and cause problems for native wildlife."

TPWD is not trying to wipe out aoudad in the region but to manage them where the opportunity is available. Texas is 97 percent privately owned, and the agency, along with WSF and TBS, focuses on building bridges with private landowners.

On state-controlled lands, such as Elephant Mountain and the Sierra Diablo Wildlife Management Area, TPWD maintains a "zero tolerance" policy for aoudad. But beyond those public land boundaries, it's about collaboration with private landowners.

Froylan Hernandez said the agency understands aoudad hunting brings in substantial income for some. "We're trying to work with landowners and give them the best data we can and let them know the impact aoudad can have on native wildlife and habitats. We don't expect everyone to want to wipe out their aoudad herds, but there seems to be a growing interest in managing them as people are seeing just how big an impact aoudad have."

Corey Mason, Executive Vice President of Conservation and COO of WSF, said the recent highly successful restoration of desert bighorn sheep in the Franklin Mountains at El Paso had given hope to what was looking like a dire situation for the species in Texas. "WSF contributed $302,800 toward that project to aid TPWD and working alongside TBS and others who were eager to get a disease-free desert bighorn herd away from aoudad. Currently, the Franklin Mountains has no aoudad and with high lamb recruitment this spring, that project has brought great hope for the species in Texas," he said.

Aoudad control is not the only component of successful desert bighorn sheep herds in Texas, but it is an important one.

It's a complex issue, but one that's being addressed with intense research, focused management, and strong partnerships, which are securing a future for the true big game icon of the Trans Pecos—the desert bighorn.

Download WSF Aoudad Position Statement Download WSF Policy on Aoudad

Contributing Author: Chester Moore is an award-winning wildlife journalist, wildlife photographer, and lifelong hunter from Texas. He operates the Higher Calling Wildlife® blog and podcast and contributes to many outdoors publications.