Park Alerts…

Bighorn Sheep Restoration

Historical Background

In the late 1800s, wildlife scientists estimate as many as 1,500 bighorn sheep roamed the mountains of the Trans-Pecos. Bighorn numbers dwindled to about 500 in 1903 due to unregulated hunting and diseases transmitted from domestic and exotic livestock. By the 1960s, they were gone from Texas.

Today, bighorn sheep once again roam in Texas. Texas Parks and Wildlife Department, the Texas Bighorn Society, wildlife conservation groups, private landowner and others worked for decades to reestablish bighorns in the state. Surveyors counted 1,280 bighorns in Texas in 2014, slightly up from 1,190 in 2013. We estimate the 2015 Texas population of bighorn sheep at 1,500.

Bighorns in the park

Family of Bighorn SheepIn 2010, TPWD released the first group of bighorn sheep in the Bofecillos Mountains of Big Bend Ranch State Park. As of early 2015, we have transplanted more than 200 sheep to the park from Elephant Mountain Wildlife Management Area and the Beach, Baylor and Sierra Diablo mountains.

The 2014 census indicates about 80 to 90 bighorn sheep in the park.

For his Master’s thesis at Sul Ross State University’s Borderlands Research Institute, Thomas Janke monitored the movements of bighorn sheep in the park. His results showed that individual animals wandered wildly from the release point during the two years of his study. Sheep moved into Mexico as well as onto areas outside of the park in Texas. Preliminarily, it appears that sheep brought from the Sierra Diablo area wandered farther on average than did those from Elephant Mountain. The majority of the relocated animals spend most of their time in the rugged canyonlands core habitat area in the southern half of Big Bend Ranch State Park.

Janke’s survey indicates that establishing sheep in the high quality habitat of the Bofecillos Mountains and canyons of the park will increase numbers and spread of bighorn sheep in Texas. It also restores the park’s native wildlife and enhances wildlife viewing.

TPWD is taking steps to help the bighorn sheep survive. This includes limiting mountain lion predation within specific zones of the park and controlling exotic species such as Barbary sheep (aoudad). Three remote “guzzlers” supplement natural desert water sources for the sheep.

Where to see bighorn sheep

Park visitors can sometimes see bighorn sheep on the flanks of Santana Mesa from La Cuesta on FM 170. Sheep also have been sighted in the interior of Big Bend Ranch State Park on the Fresno Canyon West Rim and on isolated crags near Sauceda Ranger Station.

Controlling exotics

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Burro urine and droppings contaminate this spring along the Rancherias Canyon Trail.

Aoudad

TPWD staff will continue efforts to control aoudad, an exotic from North Africa. Aoudads reproduce and spread quickly, with herds of more than 100 individuals. In the Trans-Pecos, they compete with native mule deer and bighorn sheep for space, forage and water. Large populations can damage desert plant communities. Aoudads can also pose a disease threat to wildlife and livestock.

Feral burros

TPWD policy on feral and exotic species also calls for the removal of feral burros from Big Bend Ranch State Park. The burros damage limited desert water sources and the native ecosystem. They pose threats to a range of native plants and animals, including bighorn sheep.

Burros and sheep don’t directly compete for resources now. Conflict is possible, however, as the bighorn sheep population expands.