Big Horn Sheep

The Decline of the Whiskey Mountain Bighorns

By Cat Urbigkit, Range Writing columnist for Cowboy State Daily

The Whiskey Mountain bighorn sheep herd has made Dubois, Wyoming an international stop for people interested in this species of mountain royalty, with many residents keep spotting scopes trained on the hillsides above town for constant sheep viewing. This rustic western community also hosts the National Bighorn Sheep Center.

Whiskey Mountain once held the largest concentration of wintering bighorn sheep in the country, but the herd began to decline in the 1970s. In 1975, researchers found the sheep herd was consuming more than 90 percent of the annual vegetative growth on its wintering grounds, and herd members were afflicted with poor health, indications that there was inadequate forage and the herd had overpopulated its range.

Those researchers (led by the late and sorely missed wildlife veterinarian Dr. Tom Thorne of the Wyoming Game & Fish Department) predicted that any added environmental stress could result in a catastrophic disease outbreak, which came true in the early 1990s. The population has continued to struggle since that time, with the herd currently numbering about 400 animals.

Although the herd is now only utilizing less than half the annual forage growth on its winter range, there continue to be indications that the herd is subject to some unknown nutritional stress on its summer range.

According to the draft management plan for this herd, “Underpinning the nutritional issued identified in this herd is now the persistence of bacteria and other pathogens believed to have serious health repercussions for the population.”

The herd has multiple species of bacteria related to pneumonia in bighorn sheep, as well as sinus tumors, and other diseases and parasites.

“At this point managers do not know if poor sheep health in the Whiskey Mountain Bighorn Sheep herd is strictly due to pathogens and parasites or if the persistence of pathogens and parasites is the result of nutritional stress,” according to the draft plan.

Domestic sheep and goats have traditionally been blamed for bighorn sheep die-offs, regardless of whether there was any documented contact between wild and domestic sheep.

In this case, “when and how bacterial pathogens were introduced to the bighorn sheep population is unknown, but it is likely environmental stress associated with severe winter conditions resulted in the disease outbreak and die-off event.”

The last known record of domestic sheep use in the Whiskey Mountain area was in the early 1960s, and all domestic sheep and goat grazing has been banned on the area of the Shoshone National Forest used by this herd – even the use of pack goats. Despite there being no domestic sheep in the herd area for decades, the draft plan calls for the Wyoming Game & Fish Department (WG&F) to work with the National Bighorn Sheep Center to “develop a strategy to provide educational materials to domestic sheep or goat owners” and to coordinate with federal agencies on the need to maintain separation between wild sheep and domestic sheep and goats.

In my view, that’s pretty much a waste of time and money: As if there is a domestic sheep producer in the West that hasn’t heard this refrain before. It would be far more suitable to invite wool growers to the table rather than having bighorn sheep advocates trying to tell domestic sheep producers how to manage their flocks. Sheep producers know that there are a variety of ways of keeping bighorns and domestic flocks separated, but some bighorn advocates view ridding the range of domestic sheep as the only way to ensure separation, setting the two up for conflict rather than working together.

In addition, new research on a pathogen known to cause pneumonia in bighorn sheep has been recently been documented to occur in moose, mule deer, white-tailed deer, antelope, and caribou. But WG&F maintains that these other species are not a component of the bighorn problem.

The presence of a new wolf pack on Whiskey Mountain has added a new pressure to the mix for the bighorn herd. The increased wolf activity has changed the behavior and distribution of the bighorn herd on its winter range, with the herd shifting up the mountain, into higher-elevation, less accessible, and more rugged terrain as the wolves have moved onto the lower-range winter habitat for the sheep, and the area elk population has also moved down onto traditional sheep winter range. The draft plan notes that while direct predation on sheep hasn’t been observed to be an issue, “the displacement being caused by wolves adds another potential stressor to an already nutritionally and conditionally stressed population.”

WG&F has started a three-year research project aimed at understanding lamb mortality and assessing summer habitat conditions, with the WG&F Commission kicking in $350,000 for the first year. Since much of the herd’s summer range is within the Fitzpatrick Wilderness, the U.S. Forest Service has agreed to approve the study components, including backcountry camps, experimental habitat treatments, and the use of a helicopter to capture bighorns in the wilderness area.

WG&F will hold two workshops this week to discuss the draft plan, which can be found at this link. The first workshop will be held June 5, at 6 p.m. at the Dubois Headwaters Arts and Conference Center, and the second will be June 6, at 6 p.m. in the WG&F’s Pinedale office.

Cat Urbigkit is an author and rancher who lives on the range in Sublette County, Wyoming. Her column, Range Writing, appears weekly in Cowboy State Daily.

Leave a Reply

Your email address will not be published.

*

Latest from Column

Go to Top