Biologists try again with bighorn sheep

Statewildlife o∞cials relocate a herd to a Fremont County area with amixed history.

fremont county » Where one bighorn sheep herd nearly perished, Colorado biologists hope another thrives.

Colorado Parks andWildlife biologists recently relocated nearly two dozen bighorn sheep to Badger Creek in Fremont County — a remote area feeding into the Arkansas River that recently has had a mixed history with the species.

Disease devastated the previous herd in that area, and wildlife managers are trying once again to repopulate the creek.

“We always have good hope for these things,” said Jim Aragon, Colorado Parks and Wildlife’s area wildlife manager. “And generally they’re successful. Sowe’re hoping that this one will be.”

Colorado wildlife managers last tried to introduce bighorn sheep to Badger Creek in 1991, when animals from the Rampart Range herd were relocated to the area.

For 13 years, the effort proved a stunning success — the animals flourished while living upstream from Bighorn Sheep Canyon, Aragon said.

But 10 years ago, problems emerged.

Lambs began to die before maturing, while adults — mostly ewes — showed signs of a failure to thrive, Aragon said. The culprit appeared to be pasteurella bacteria, which can often lead to pneumonia in bighorn sheep, he said.

Wildlife managers removed the last 13 ewes in the area last year to place them in aWyoming disease research facility, according to the agency.

There, the problems persisted: Lambs born at the facility continued to carry the bacteria and died, Aragon said.

The exact cause of the herd’s disease remains unknown, although it likely started with a bighorn sheep that wandered into Badger Creek from elsewhere in Colorado, he said. The bacteria spreads only from ewe to lamb, or by close contact.

“It’s not something that’s in the area,” Aragon said. “It’s something that’s really transmitted between animals.”

The latest herd hails from Chancellor Ranch in Chacuaco Canyon in southeast Colorado, where wildlife managers captured the sheep using net guns fired from helicopters, allowing them to fly the animals to Fremont County.

Researchers also placed satellite transmitters on someanimals— devices that can e-mail the position of those sheep to researchers twice a day, the agency said.