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Hunting bighorn sheep ewes to save the herd

Bighorn sheep lambs and ewe in Yellowstone National Park. (Jacob W. Frank/NPS)

Few hunting experiences are as rugged, challenging and elusive as stalking a bighorn sheep. 

Interested Wyoming residents typically wait decades, if not even a lifetime, before drawing a ram license in their home state. Sheep herds are relatively small, scattered and found in remote, challenging terrain compared to pronghorn, deer or even elk. And the opportunity is once in a lifetime. Draw a Wyoming bighorn sheep ram tag, and whether or not you fill it, you’ll never get another. 

But ewes are a different story. Licenses for hunting female sheep are a newer offering of the Wyoming Game and Fish Department and the agency has ramped up quotas in the last couple of years.

Not everyone is happy about that. Critics point out that bighorn sheep are rare, and argue we should not be shooting the reproductive members of the herd. But wildlife researchers and biologists contend that once bighorn sheep herds reach capacity, members are going to die one way or the other, whether by bullet, bug or bad winter. 

Wildlife managers may one day be able to place some of those extra sheep in mountains near Jeffrey City thanks to a recently passed bill. Though even with a possible reintroduction, biologists still ask the public to bear with them while they use hunting as a way to kill a smaller number of animals to save a larger portion of the herd. 

Debating a hunt

Hesitation toward hunting female big game animals, the ones responsible for producing offspring and thus most important for sustaining herds, has always carried some controversy, said Kevin Hurley, vice president of conservation for the Wild Sheep Foundation. 

“When I was in Wildlife 101 almost 50 years ago, they talked a lot about whitetail deer hunting in Vermont or Pennsylvania and, ‘how dare you suggest killing a whitetail doe?’” he said. “Well, when whitetail numbers got out of control, it switched to ‘maybe we should have harvested some of these reproducing females.’”

Ram and ewe bighorn sheep in Yellowstone National Park. (Diane Renkin/NPS)

People like to think the more animals on the landscape, the better. And it’s easy to see the basis for that argument. Before European settlers, between 1.5 million and 2 million bighorn sheep lived across the West. Settlers overharvested the animals for food and market, and disease took care of the rest. Now about 70,000 roam western states

Despite a bighorn sheep’s ability to live in some of the country’s harshest landscapes, they’re remarkably fragile. If pathogens that cause pneumonia enter a herd, often contracted when a bighorn sheep gives a nose-to-nose hello to a domestic sheep carrying the disease, herds could plummet. 

Take the Whiskey Basin bighorn sheep herd. Biologists spent years capturing sheep from the iconic herd outside of Dubois in the Wind River Range and sending them across Wyoming and the West to start new populations. But a few decades ago, the herd crashed because of pneumonia and has never fully recovered.

The Whiskey Basin’s sad tale, along with fledgling new populations, meant that for many years, bighorn sheep hunting in Wyoming was even more limited than today. But as years passed, and other herds like the ones near Jackson and in the Ferris-Seminoe mountains in central Wyoming grew, so did opportunity. Soon, some of Wyoming’s bighorn sheep herds grew from tens of individual sheep to hundreds. 

But biologists worry that the herds’ successes, if wildlife managers aren’t careful, could also be their downfall. 

Tale of two herds

Look at a growth line of the Jackson bighorn sheep herd, and you will see the story of disease and bad winters. Biologists think the area has enough food to support about 400 animals. Creep closer to 500, as the herd did in 2000, and the numbers collapse. The reason became clear more recently through research with the University of Wyoming. 

“Body fat on the females dropped significantly as the number of sheep increased,” said Aly Courtemanch, Game and Fish wildlife biologist in the Jackson region. “They had less fat, were more infected by pathogens and pregnancy rates also dropped. Those are all pretty clear signs of too many sheep on the landscape.”

The herd so far has seemed able to bounce back, but Courtemanch worries one day they won’t be so resilient. So two years ago, Game and Fish wildlife managers introduced ewe hunting. Instead of only allowing hunters to kill male bighorn sheep, the ones with the partial or full curl horns that wind around the sides of their heads, hunters can now kill females, too. 

The Ferris-Seminoe herd tells a different story. Biologists restarted the herd in 2009, and it’s now the only one in Wyoming that remains disease-free. With about 400 sheep, it’s healthy, robust and growing, said Daryl Lutz, Game and Fish’s Lander region wildlife management coordinator. 

But when bighorn sheep — or plenty of other species for that matter — exceed their habitat’s carrying capacity, they start to wander. 

Bighorn sheep ewe with lamb on Mount Washburn in Yellowstone National Park. (Neal Herbert/NPS)

“Mostly that’s rams foraying, looking for love during the rut, but we also know ewes will go looking to expand their range,” Lutz said. 

And once a sheep makes a foray into new habitat, they risk encountering the pathogens that cause pneumonia and bringing them back to the herd.

In response, the department proposed hunting 20 ewes or lambs from the herd last year, and this year they’re proposing hunting another 30. 

UW professor Kevin Monteith isn’t going to advocate for more hunting. It’s not his role, he said. But he and graduate students in his program have studied bighorn sheep in the Jackson and Whiskey Basin herds for years, and what they found is pretty clear: Keep too many sheep in one area, at some point, a bunch are going to die. 

So for him, it’s a tradeoff. If we want more sheep on the landscape but don’t have more food for them to eat, we have to accept that at some point, they will start falling over. 

Starting again

Critics of ewe hunting will say instead of hunting females, the state should translocate them. 

Right now, nowhere in Wyoming needs more sheep, but that could soon change.

The Wyoming Legislature passed a wonky wildlife bill this year to protect public land grazing rights in the Sweetwater Rocks area from possible federal restrictions should bighorn sheep reestablish themselves or be brought there by humans. The bill states that if the federal government tries to restrict grazing rights because of fear of disease, Game and Fish will remove all the bighorn sheep from the hypothetical herd. 

Similar legislation was created years ago to address possible conflict and concerns with sheep in the Sierra Madres, Lutz said. While it may sound draconian, easing sheep producers’ fears is the first step in paving the way to a possible reintroduction. 

But there’s no guarantee of a new herd. The bill won’t go into effect until January 2026, or if Congress passes a mirror bill. At that time, Game and Fish will need to talk again with area landowners and anyone else interested. 

If all that happens, and the department proceeds with creating a new herd, Lutz said the starter sheep will likely come from that disease-free, and relatively nearby, Ferris-Seminoe population. 

“That’s why keeping the Ferris-Seminoe herd healthy is important,” Lutz said. “Not just for the sake of the herd, which is the most important reason, but right now it’s the only healthy herd in the state.”

This article was originally published by WyoFile and is republished here with permission. WyoFile is an independent nonprofit news organization focused on Wyoming people, places and policy.