Nature Notes; AOUDAD: For Wildlife Managers, a hardy newcomers success raises tough questions

This is Nature Notes. Our look at the natural world in West Texas. From the prairies of the Llano Estacado to the borderlands of the Chihuahuan Desert.

Some visit the Big Bend for a day or a week – and have their fill. But an intrepid few find they’re suited to this harsh terrain, and make it their home.

Native to northern Africa, aoudad – or Barbary sheep – were introduced to Texas the 1950s. In the desert-mountains of the Trans-Pecos, they’ve found a land in which they can flourish. Watching aoudad storm up a rocky slope in the Guadalupe, Davis or Chisos mountains, it’s hard not to admire these hardy newcomers.

But as their populations swell, aoudad appear to be edging out native species – mule deer, pronghorn, bighorn sheep. And that raises tough questions for landowners and wildlife managers.

From Marfa Public Radio, with the Sibley Nature Center in Midland, this is Nature Notes. I’m Dallas Baxter.

Introduced on ranches and state land, aoudad were an exciting new game animal for Texas hunters. The rams can weigh 250 pounds, with 20-inch horns. They can get all the water they need from their food. They’re at ease in the roughest terrain.

And they’ve flourished in the Trans-Pecos.

Shawn Gray is mule deer and pronghorn program leader at Texas Parks and Wildlife.

“They do very well here – we always say it’s like the Garden of Eden compared to where they came from, the northern part of Africa.”

It’s open season on aoudad in Texas, and aoudad hunts are valued revenue for landowners. But it’s the familiar story of an “invasive” or non-native species: the aoudad’s success may threaten other creatures.

In the 80s, parks and wildlife began an ambitious project to reintroduce desert bighorn in the Trans-Pecos. The sheep had vanished in the 50s. The project has seen success. Biologists now estimate a Texas herd of 1,500, in mountain ranges across the region.

Aoudad are hardier and more aggressive than bighorn. In reproduction, they outpace the sheep. While bighorn have a single breeding season each year, aoudad breed throughout the year.

On the slopes that are bighorn habitat, massive aoudad herds can decimate food sources.

Froylan Hernandez is parks and wildlife’s bighorn program leader.

“For us it’s an issue, because they can be out there in tremendous numbers. We just did surveys and we found surveys of 200 animals, all in one group. That kind of concentration in an area – you can just imagine what kind of impact that has on the vegetation.”

Native wildlife are specialists in range and diet. But aoudad are generalists. While bighorn sheep rarely leave steep, exposed slopes, aoudad will range into other habitats for food, Hernandez says.

“You’ll see aoudad out in the flats, out in the rolling stuff and just in the rough stuff. They can affect pronghorn because they’re out in the flats. They can affect mule deer cause they’re out in the rolling stuff. And they can affect bighorn because they’re in the rough stuff.”

Parks and wildlife works aggressively to control aoudad populations on state lands. Staffers make regular helicopter hunts, shooting as many aoudad as possible.

In 2007, news that parks and wildlife was killing wild burros in Big Bend Ranch State Park triggered a public outcry. And there’s opposition now to the department’s aoudad hunts.

Jose Etchart, a master’s student at Sul Ross State University, is studying aoudad in the Sierra Vieja mountains. It’s one of the first scientific studies of aoudad in Texas.

Etchart’s findings suggest aoudad and bighorn diets do overlap. And aoudad may be dominating water troughs installed for bighorn, Etchart says.

Etchart himself guides aoudad hunts. He admires the animal. But he says aoudad are quickly becoming a “pest” in West Texas.

“I’ll tell you what, there is competition going on, but we do need to give them some credit – because they’re amazing creatures, how they adapt and have been using these areas. My mentality is, you have this mountain, how many animals can you keep on that mountain? How many mouths can you actually have on that mountain? What are your goals – trying to conserve the bighorn or trying to keep the bighorn and the aoudad at the same time?”

Conservation of bighorn and other species may demand aoudad control. But decades after its arrival, it’s hard to regard the aoudad as a “non-native.” It’s now part of the West Texas landscape.

Nature Notes is underwritten by the Dixon Water Foundation and is produced by Marfa Public Radio in cooperation with the Sibley Nature Center in Midland, Texas. This episode was written by Andrew Stuart. I’m Dallas Baxter. Thanks for listening.

PROMO – Native to North Africa, aoudad were introduced to Texas the 1950s. They’re at home in the most rugged terrain, and they’ve flourished in the Trans-Pecos. But their success appears to threaten native species. And that raises tough questions for landowners and wildlife managers. Join us at 7:45 a.m. and 4:45 p.m. on Tuesdays and Thursdays. The secrets of the natural world revealed on Nature Notes. Tuesdays and Thursdays on this public radio station.