NDGF plans to transplant bighorn sheep

In an effort to avoid devastating disease and future car accidents, the North Dakota Game and Fish Department is gearing up to capture and transplant about 10 to 15 bighorn sheep from the Theodore Roosevelt National Park’s North Unit.

Using helicopters and net-gunners contracted out of Colorado, NDGF Bighorn Sheep Biologist Brett Wiedmann said the core group of sheep will not be touched.

The operation is presently slated for Feb. 13.

“We’re going to grab two of the older ewes, is the plan, that originally came here from Montana, and then we’re going to grab just a bunch of offspring,” Wiedmann said.

The animals are going to be released in one group about 15 to 20 miles northeast of the park, or half will be released in the northern Badlands and half in the southern portion.

“From the park perspective, it’s a good thing in terms of using those animals to augment other populations, because they’re just doing so well,” said Mike Oehler, wildlife biologist for TRNP.

In an effort to reintroduce the species to North Dakota in 1956, 18 bighorn sheep from British Columbia were transplanted in western North Dakota.

Fifty years later, 19 of what Wiedmann says are referred to as “genetic golden nuggets,” were brought in from Montana and released on U.S. Forest Service land east of the park’s North Unit.

“Original park sheep” are on the park’s west side and Montana sheep inhabit the park’s east side along U.S. Highway 85.

After about two and a half years, the sheep started to winter in the park, spending about nine months out of the park and three inside.

“Sheep move and there’s probably more forage for them in the park, in deep snow,” Wiedmann said. “We were hoping they would not cross into the park, simply because of the fact there is so much highway traffic on Highway 85. We found them a few times bedded right off the highway.”

Last year the sheep moved west, eventually hitting the 8-foot-high park fence, causing them to gather near the highway.

Three ewes were lost to vehicle accidents.

“Our goal was to manage it at about 50 because there is a lot of habitat east of the park,” Wiedmann said. “As soon as we started losing them to vehicles, now we’re going to try to maintain them at 20 to 30 animals.”

Wiedmann said during a flyover of bighorn-sheep area near the park on Wednesday, two-thirds of a 40-strong herd are inside the park, while the rest remain outside park boundaries.

Typically, when bighorn herds exceed 40 members, the NDGF will move a few of the animals to other herds or start new ones as bigger herds carry greater risk for deadly diseases, Wiedmann said.

Depending on reproduction rates and lambing successes, plans are to keep capturing offspring from the same herd, moving them to different areas of the Badlands, Wiedmann said.

Disease is nothing new for bighorns across the country, an issue Wiedmann cites it as the No. 1 challenge to wild-sheep management.

Bighorn populations in Montana, Washington and Nevada are presently being ravaged by disease.

North Dakota’s last major die-off was in 1998, when two bighorn sheep populations were completely wiped out, both located south of Interstate 94, according to North Dakota Outdoors magazine.

“We discovered that domestic goats were grazed for leafy spurge about two miles away,” Wiedmann said, according to the magazine. “The goats were likely the disease vector for the bighorn sheep.”

Wiedmann said another concern for roaming bighorn sheep is possible contact with domestic sheep.

“We have a policy that if we know a bighorn has interacted with domestic sheep or goats, we kill that animal because it can wipe out 100 healthy bighorns when it returns to the herd,” Wiedmann said, according to the magazine.

The NDGF is not new to the relocation process.

As of February 2006, in the last 50 years the NDGF had conducted similar operations 42 times in the state and eight times out-of-state, according to the magazine.

For more information on the capture and transplant process, visit www.gf.nd.gov.