Tag Archives: mt. hull herd

Sheep Pneumonia Kills 11 Okanogan Bighorns; Monitoring Continues

A pneumonia outbreak may have run its course in a herd of Okanogan County bighorn sheep after killing nearly a dozen this past winter, but wildlife managers will keep monitoring the animals.


“Today the herd looks healthy, the lambs are healthy and fun to watch,” said WDFW wildlife biologist Jeff Heinlen, who was observing the Mt. Hull sheep this morning. “Boy, they’re active, up on the rocks, jumping around.”

It’s been a month and a half since the last new mortality and Heinlen counted 44 sheep, including 10 two-week-old-or-so lambs, along with 15 rams amongst the herd that roams across the mountain just southeast of Oroville.

In mid-March, WDFW reported one ram had been confirmed to have died from Mycoplasma ovipneumoniae — M. ovi for short — and afterwards asked the public to keep an eye out for any others displaying symptoms of the highly contagious bacteria.

Typically it starts with infected animals licking their lips, then coughing before eventually foaming at the mouth right before they die.

The agency’s early April bimonthly Wildlife Program report states that all totaled nine rams, one ewe and one of last year’s lambs are known to have succumbed, but that no new cases have been seen since March 30.

Heinlen says that six carcasses were sent to a Washington State University lab which confirmed they had all died from sheep pneumonia. Typically it is picked up from domestic herds.

It wasn’t clear why mortality was so concentrated among rams,  but possibly because a bachelor group came into contact with someone’s sheep.

Both WDFW and the Colville Tribes, which comanage the herd, withdrew the two ram and four ewe permits that were otherwise going to be available for this fall’s seasons due to the outbreak.

“There are still some pretty nice rams,” noted Heinlen.

While his latest count of 44 sheep is well below the 71 he saw in February and 80 to 82 tallied by the tribes during a January aerial survey, the animals have been using more forested terrain that makes it harder to get a headcount.

Heinlen said it’s easier to spot dead rams on the landscape due to their body size and large horns, but also said he wasn’t seeing eagles or magpies, which would suggest more carcasses on the ground.

This is the first time that M. ovi has been found in the Mt. Hull herd, he reported. It has struck others in Washington, including Yakima River Canyon, Tieton River and Snake-Grande Ronde populations.

“Bottom line, we’re not seeing the catastrophic die-off of other herds. We don’t know if it’s run its course, but we will continue to monitor the herd,” Heinlen said.

They’ll be watching those playful newborn lambs closely in hopes none come down with symptoms.

WDFW Asks For Public Help Monitoring Okanogan Bighorns After 1 Dies From Sheep Pneumonia


The Washington Department of Fish and Wildlife (WDFW) asks members of the public to report sightings of bighorn sheep that are obviously ill in Okanogan County after a bighorn ram from the Mt. Hull herd was recently confirmed to have died from pneumonia caused by a highly infectious bacteria. While posing no health threat to humans, Mycoplasma ovipneumoniae, known as M. ovi, can decimate bighorn populations and kill lambs for many years, preventing herds from repopulating.


At this time, only a single ram from the herd near the Canadian border has tested positive for pneumonia. Testing on additional animals is currently underway. While WDFW biologists and veterinarians await results, they are partnering with biologists at the Colville Tribes to increase visual monitoring of the Mt. Hull herd. And they are asking for help from the public.

“This is a highly visible herd. These sheep are in orchards and among houses,” said WDFW Biologist Jeff Heinlen. “Because we can’t be watching all the time, we are asking people to alert us if they notice sheep that appear lethargic, coughing or showing nasal discharge. This helps us assess the health of the herd.”

There is also a potential for wandering sheep to pass M. ovi to animals in other herds, such as the Omak Lake herd on the Colville Reservation to the south, the Sinlahekin herd to the west, or herds to the north across the border in British Columbia.

“In 2012 the Colville Tribes conducted a genetic analysis between the Sinlahekin, Mt. Hull, and Omak Lake herds, showing us that the Omak Lake herd was likely founded by individuals from the Sinlahekin herd, but may have been in contact through immigration event(s) with the Mt. Hull herd in the past,” said Colville Tribal Biologist Eric Krausz. “We have documented collared bighorn sheep traveling from Omak Lake to Mt. Hull, so we know bighorn sheep from these distinct herds travel back and forth on occasion and likely come into contact with one another.”

Because of this, WDFW asks to also be alerted if bighorn sheep are observed in places they aren’t normally seen. The Mt. Hull herd’s typical range is from approximately Tonasket to the Canadian border north of Oroville. If sheep are seen outside that area, or notably sick bighorn sheep are observed, please call Jeff Heinlen at (509) 826-7372 and leave a message or email Jeffrey.Heinlen@dfw.wa.gov.

While it is biologically possible for uninfected domestic sheep or goats to become infected by contagious bighorns, cross-species transmission of M. ovi is much more common in the reverse direction. The bacteria typically causes only mild and temporary symptoms in domestic sheep and can reduce growth rates, but serious illness and death is rare. In contrast, most bighorns that become infected due to close contact with domestic sheep or goats succumb to pneumonia, and some that survive pass it to newborn lambs that similarly lack immune protection.

There are approximately 17 bighorn sheep herds across Washington, two within the bounds of the Colville Reservation.