Recapturing historic range: Bighorn sheep transplants aim to bolster Montana herds

Recapturing historic range: Bighorn sheep transplants aim to bolster Montana herds

Source: Missoulian
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HELENA — It took a moment for the first ewe to make her decision.

With the door wide open and sunlight beaming into the stock trailer, she finally leapt and hit the ground running with effortless strides that quickly put distance behind her. Then the other 19 bighorn sheep took the cue, charging out across the grassy hillside and into the steeper country above.

The Beartooth Wildlife Management Area north of Helena is empty this time of year if humans are the only measure of population. But while closed to the public until May 15, the 32,000 acres are far from unoccupied.

Whitetail deer teemed through the knee-high bunchgrass of the foothills and herds of elk moved into a wooded draw as Montana Fish, Wildlife and Parks biologist Cory Loeker drove deeper into the WMA, followed by members of a local conservation group who came to see the day’s event. The destination was Willow Creek, and in tow were 20 bighorn sheep captured near Winifred the day before.

“The whole Missouri River is their historic range,” he said, “and these fires have really opened up some steep escape cover.”

In November, the Montana Fish and Wildlife Commission heard testimony on the challenges biologists face with diseases and bighorn sheep. Outbreaks of pneumonia have caused some of the state’s premier herds to collapse, with many struggling to recover.

The Missouri River Breaks hosts perhaps the most well-known bighorn sheep herds in the world for producing some of the largest rams harvested by hunters each year.

With populations growing to carrying capacity in Hunting District 482, FWP began voicing concerns in 2014 that overabundance could lead to a die-off. Particularly with young rams, the propensity for bighorn sheep to roam is of chief concern for game managers, and roaming is more likely if population densities are too high.

Pneumonia in bighorn sheep has largely been traced back to contractions from their domestic cousins. The issues with domestic and wild comingling have become contentious at times between bighorn advocates and domestic producers.

As Montana Woolgrowers President Dave McEwen said at symposium earlier this month, domestic sheep suffer pneumonia as well.

“We know what causes that, we know the triggers that cause it and we manage for it so it’s a manageable issue rather than a crisis issue,” he said.

Disagreements on disease spread and management responsibilities aside, FWP considers comingling such a risk that it removes wild sheep known to have come in contact with domestic herds.

Montana’s 5,700 bighorn sheep population is below the 6,500 in 2007. The difference is even more pronounced in large die-offs in the Highlands, Rock Creek and Bitterroot, but offset by growth in the Missouri River Breaks herd.
Recognizing the potential for an outbreak in the Breaks, in 2014 FWP asked the commission for permission to move sheep to South Dakota. The commission did not agree, however, instead pushing a policy to find an instate home for the sheep, and pointing to the bighorn management plan calling for creation of five new herds in Montana.

The problem, FWP biologists say, is they have no suitable places to establish a new herd. Public land with suitable habitat far enough away from domestic sheep is a limited commodity in Montana. Augmenting disease-carrying herds with healthy sheep has also proved ineffective.

With the commission’s direction, in 2014 FWP began transplanting bighorn sheep into the Beartooth despite the ’09 die-off. So far, indications of herd health such as lamb recruitment have been good, Loeker said.

Concerns about the burgeoning population in the Breaks again brought FWP to the commission last November. Testimony at the hearing included some sobering details about bighorn diseases and challenges with testing.

“The bottom line is there is still a lot we don’t know, but we know more than we used to,” Jennifer Ramsey, FWP biologist told the commission as reported by the Billings Gazette.

The commission approved transport of 30-45 sheep to the Beartooth and the aptly named Sheep Creek. Loeker says the transplants will nearly double the population in HD455 as managers aim to better establish a northern and southern herd in the district. He would ultimately like to see a population of about 200 bighorn sheep in the area.

An earlier transplant into Sheep Creek drew public attention when some of those sheep wandered almost 20 miles, coming in contact with a domestic herd. FWP removed those animals as a means of protecting the overall population.

Last week’s transplant on the Beartooth was the final of the year and included 20 ewes and lambs. FWP captured them near Winifred using helicopters and net guns. Each received and ear tag and health examine ahead of the transplant.

The all-female release is by design, Loecker said. Older rams tend to “freak out” when in the trailer, and with about 90 percent of the ewes pregnant, plenty of more rams are on the way.

While the sheep bring the genetics of some of the biggest rams in the world and that certainly does not hurt trophy potential, much of the productivity of the Breaks is due to exceptional habitat quality, he said, pointing out that the Breaks herd came from sheep captured along the Rocky Mountain Front.

During recent surveys, ewes weighed in the Breaks came in at 180 to 195 pounds compared to a similar survey in Augusta where 150 was the top weight.

As Loeker climbed back in his truck, he voiced a sense of cautious optimism.

“They’ve done really well in here since the die-off we saw in ’09, especially the lambs,” he said. “But they do climb and crash.”