Montana Fish, Wildlife & Parks officials killed three bighorn sheep today on Mount Jumbo near Missoula due to disease risk after the bighorns were found mingling with domestic sheep.
Domestic sheep can carry bacteria and viruses that are harmless to them but can cause an often fatal pneumonia outbreak in bighorns. Pneumonia spreads quickly, sometimes killing over half or more of a bighorn sheep herd.
The City of Missoula permits domestic sheep to graze on Mount Jumbo every spring and summer as part of an effort to reduce leafy spurge, an invasive plant species that covers parts of the mountain and competes with native wildlife forage. FWP and the City of Missoula have a bighorn and domestic sheep agreement and protocol to reduce the risk of bighorn sheep interacting with domestic sheep.
Vickie Edwards, FWP Missoula-based wildlife biologist, says that this is the first time since 2000 that there has been any documented interaction between the wild and domestic sheep population.
“We work closely with the city to ensure that the sheep do not interact, but these rams were in a spot we would not expect them to be and co-mingled before the herder could prevent the interaction,” Edwards said. “The herder did a great job following the protocol to ensure that the City of Missoula and FWP staff was able to respond quickly.
Officials closed the nearby hiking trails before dispatching the sheep early this afternoon.
“This is an extremely unfortunate incident, but we hope that by dispatching these three sheep we have prevented potential disease exposure to the rest of the herd,” Edwards said.
The bighorns will be sent to the state wildlife lab in Bozeman for testing that will provide FWP with additional information on the health of the sheep and their herd. The bighorns were part of the Bonner herd which was last affected by pneumonia in 2010 and lost nearly 60% of its population to the disease and culling efforts. The source of that pneumonia outbreak is unknown.
The domestic sheep currently grazing Jumbo will be moved off the mountain to the North Hills until officials are able to determine whether other bighorns may be in the area.
(Report by Montana FWP)