Back in October I took a break from elk hunting to photograph bighorn
sheep at the National Bison Range in Moise. I was surprised how close one ram
let me to get, and then I noticed something was wrong. Several times he dropped
his head to the ground and struggled to lift it back up. The weight of his
heavy horns he long proudly carried had apparently become too burdensome. He
was dying. I returned the next day and found his body.
After posting a photo of the ram on Facebook, and speculating about his death, my friend Stacy Courville, a wildlife biologist with the Confederated Salish and Kootenai Tribe, said the sheep most likely died from pneumonia, which had recently infected the Bison Range. So I talked to Jeff King, the U.S. Fish and Wildlife Service manager who oversees the range. Courville was correct: A bacteria called Mycoplasma ovipheumonia had infected the bighorn populations, causing pneumonia. More than 35 wild sheep had died in just a few months. King and others suspect that the bacteria was transferred to the wild herd from a domestic sheep herd about a mile west of the range.
Once the bacteria infects a herd of wild sheep, it can be devastating, and not much can be done.
After posting a photo of the ram on Facebook, and speculating about his death, my friend Stacy Courville, a wildlife biologist with the Confederated Salish and Kootenai Tribe, said the sheep most likely died from pneumonia, which had recently infected the Bison Range. So I talked to Jeff King, the U.S. Fish and Wildlife Service manager who oversees the range. Courville was correct: A bacteria called Mycoplasma ovipheumonia had infected the bighorn populations, causing pneumonia. More than 35 wild sheep had died in just a few months. King and others suspect that the bacteria was transferred to the wild herd from a domestic sheep herd about a mile west of the range.
Once the bacteria infects a herd of wild sheep, it can be devastating, and not much can be done.
“Mycoplasma ovipheumonia has no
cell wall, so antibiotics do not work on it,” says Mark Penninger, an
Oregon-based wildlife biologist who heads up the bighorn sheep program for the
U.S. Forest Service. “It is carried with no ill effects by many domestic sheep
and goats, but is deadly to wild sheep. Our wild sheep have not evolved with
this pathogen. It can sometimes kill wild sheep by itself, but is often a
precursor that compromises the respiratory system's ability to move things,
such as bacteria and viruses, out with mucous. Then the sheep die when their
body responds by producing more mucous, which results in pneumonia. It is quite
the dilemma when trying to protect and restore bighorn populations.”
When a bighorn sheep population is initially infected, often as many as a third, and sometimes up to 90%, of the herd may die of pneumonia. Most survivors are apparently immune, but their lambs are not and usually die before weaning. In some populations, annual pneumonia outbreaks in lambs continue for decades after the initial infection, which prevents the population from bouncing back. In other populations, lamb survival returns to normal relatively quickly. Why some populations recover and others do not is one of the most important questions scientists are trying to answer. Some researchers hope that wild sheep herds could eventually develop an immunity.
But in the meantime, bighorns are being infected and dying throughout their range.
More than 90 bighorns recently died of pneumonia near Plains, and another 39 died near Gardiner. “We’re losing hundreds of wild sheep to this disease every year and it is decimating herds across the west,” said Kyle Meintzer, director of the Wild Sheep Foundation (WSF) based in Bozeman. “For example, in 2013, 400 wild sheep in California were lost, and that’s 80 per cent of what was the largest herd in the state. Wildlife managers were forced to sacrifice the herd in the Tendoy Mountains in Montana due to recurring pneumonia and low lamb survival. Wildlife managers, with the help of hunters, will remove 100 per cent of the herd and later will repopulate the herd with healthy bighorns.”
Unfortunately, killing wild sheep because of suspicion of exposure is the prudent thing to do in many cases, according to Mark Penninger. “A wandering wild sheep can cover a lot of miles and return to its herd with death in its breath. Killing one sheep could prevent the loss of an entire herd. Capturing and testing is rarely practical due to urgency and terrain.”
When a bighorn sheep population is initially infected, often as many as a third, and sometimes up to 90%, of the herd may die of pneumonia. Most survivors are apparently immune, but their lambs are not and usually die before weaning. In some populations, annual pneumonia outbreaks in lambs continue for decades after the initial infection, which prevents the population from bouncing back. In other populations, lamb survival returns to normal relatively quickly. Why some populations recover and others do not is one of the most important questions scientists are trying to answer. Some researchers hope that wild sheep herds could eventually develop an immunity.
But in the meantime, bighorns are being infected and dying throughout their range.
More than 90 bighorns recently died of pneumonia near Plains, and another 39 died near Gardiner. “We’re losing hundreds of wild sheep to this disease every year and it is decimating herds across the west,” said Kyle Meintzer, director of the Wild Sheep Foundation (WSF) based in Bozeman. “For example, in 2013, 400 wild sheep in California were lost, and that’s 80 per cent of what was the largest herd in the state. Wildlife managers were forced to sacrifice the herd in the Tendoy Mountains in Montana due to recurring pneumonia and low lamb survival. Wildlife managers, with the help of hunters, will remove 100 per cent of the herd and later will repopulate the herd with healthy bighorns.”
Unfortunately, killing wild sheep because of suspicion of exposure is the prudent thing to do in many cases, according to Mark Penninger. “A wandering wild sheep can cover a lot of miles and return to its herd with death in its breath. Killing one sheep could prevent the loss of an entire herd. Capturing and testing is rarely practical due to urgency and terrain.”
What can be done? The most
viable – yet controversial – proposals involve separating wild sheep from
domestic sheep by large distances so they cannot come in contact. “The science
is clear that domestic and wild sheep can’t live together,” says Kevin Hurley,
Conservation Director for WSF.
In the Salmon River country of Idaho, where 76-percent of the bighorn populations was lost to pneumonia, legal battles ensued between sheep herders, conservationists and the U.S. Forest Service when the Payette National Forest decided to keep domestic sheep off grazing leases within bighorn sheep range. In 2008, a U.S. District Judge ruled in favor of the decision. But leaders of hunter-conservation organizations, and wildlife biologists and mangers with state and federal agencies, would prefer to work with the sheep ranching industry to find viable solutions rather than fight things out in court.
The WSF recently met with members of Congress and federal wildlife agencies on solutions to create safe zones against deadly pneumonia bacteria and viruses that are infecting wild sheep herds in the U.S. “Having a disease-free zone around the new herd is necessary to prevent new infection and assure the success of restoration,” says Kyle Meintzer.
In the Salmon River country of Idaho, where 76-percent of the bighorn populations was lost to pneumonia, legal battles ensued between sheep herders, conservationists and the U.S. Forest Service when the Payette National Forest decided to keep domestic sheep off grazing leases within bighorn sheep range. In 2008, a U.S. District Judge ruled in favor of the decision. But leaders of hunter-conservation organizations, and wildlife biologists and mangers with state and federal agencies, would prefer to work with the sheep ranching industry to find viable solutions rather than fight things out in court.
The WSF recently met with members of Congress and federal wildlife agencies on solutions to create safe zones against deadly pneumonia bacteria and viruses that are infecting wild sheep herds in the U.S. “Having a disease-free zone around the new herd is necessary to prevent new infection and assure the success of restoration,” says Kyle Meintzer.
Steve Torbit, executive
director of the National Wildlife Federation’s Rocky Mountain Regional Center in
Boulder, Colorado, calls for “livestock producers and wildlife folks to roll up
their sleeves and work together to find areas suitable for domestic sheep.”
Torbit and other bighorn advocates hope they can persuade western sheep
ranchers and federal officials to develop a strategy that will allow bighorn
sheep populations to expand through conservation and further reintroductions
across the West. “I don’t want to start a new range war, because it’s not good
for anybody, and it’s certainly not good for wildlife,” he says. He favors a
collaborative process that brings ranchers, sportsmen, tribes and
conservationists together to protect the range and wildlife but still allows
ranchers to thrive – creating safe zones for wild sheep far from domestic
sheep, and setting aside other zones for domestic sheep far from bighorn
habitat.
As Kevin Hurley puts it: “If
you believe in compromise and conservation, both sides have to give up
something.”
