Doug Leier: State's bighorn sheep 'roller coaster tale'
The history of bighorn sheep in the southern badlands of North Dakota is a roller coaster tale. And unfortunately, it’s been mostly down of late.
That’s how editor Ron Wilson described the situation in a feature article in the February 2020 issue of the State Game and Fish Department’s magazine, North Dakota Outdoors.
Those bighorns, about 20 of them that roam the rugged terrain south of Interstate 94, have been the topic of many discussions since last fall. At public advisory board meetings starting in late November, Game and Fish administrators discussed the possibility of removing the southern badlands bighorns and bringing in all new animals.
At one point, the bighorn population south of the interstate likely topped 100, but since the late 1990s, four separate populations were decimated by disease. Two of those populations or bands died out completely.
Brett Wiedmann, Game and Fish Department big game biologist, said that disease is one of the most troubling hurdles for bighorns. “In 1997, there was a pneumonia die-off and the population declined to about 20 animals at that time,” Wiedmann said.
It was determined the wild animals were infected by Mycoplasma ovipneumonae. This bacterium that leads to the death of bighorns is common in healthy domestic sheep and goats, and they can pass it on to wild bighorns through direct contact.
“We just kept getting these pulses of pneumonia and very low lamb recruitment,” Wiedmann said.
What big game biologists learned over time is that Mycoplasma can’t survive without the host. Understanding that, introducing healthy animals into a population of pneumonia survivors is futile when trying to rebuild the herd.
To have a healthy, and eventually growing bighorn sheep population south of the interstate, Wiedmann said all of the existing bighorns must first be removed from the landscape.
Game and Fish had intended to get that process started as early as this fall by offering hunting licenses that would have allowed taking of rams and ewes. “We want hunters to be the first option in harvesting the ewe population,” Wiedmann said. “What’s important is that we get them all and that’s the tricky thing.”
However, Game and Fish has now put those plans on hold as a survey this winter found domestic sheep, which could pose a risk of infecting any new bighorns brought in, within a fairly close distance of a planned release site. “We have had to put the brakes on the removal effort,” said Jeb Williams, Game and Fish wildlife division chief. “We will be giving it some additional time to try and come up with options so we feel comfortable, and responsible, in bringing in healthy bighorn sheep from Montana.”
Wiedmann said the bighorn sheep population north of the interstate, which includes approximately 30 animals in the North Unit of Theodore Roosevelt National Park, stands at about 330.
“It’s a very realistic possibility that we could eventually have 500 bighorn sheep in the northern badlands where there is a lot more suitable habitat than down south,” Wiedmann said. “And, you know, we’d be pretty happy if we ultimately had 75 bighorns south of the interstate.”