Sullivan bighorn sheep boost to other herds

A small but tenacious herd of Rocky Mountain bighorn sheep in northeastern Washington is being tapped once again to boost a struggling herd elsewhere in the state.

Washington Department of Fish and Wildlife biologists are attempting to capture two or three rams from the Hall Mountain herd that ranges near Sullivan Lake.

If the effort is successful, the rams would be transported and released in southeastern Washington as a “genetic rescue” attempt for the Tucannon River herd, said Rich Harris, department big-game special species manager.

A shortage of rams in the Tucannon herd could be causing inbreeding that might account for poor survival of lambs, he said.

But sportsmen in the region are concerned that the Pend Oreille County herd could be threatened by removing more rams.

The Hall Mountain herd was established in 1972 from bighorns captured in Canada’s Waterton National Park and then with sheep from the Thompson Falls area of Montana.

“We know that bighorns are native to Hall Mountain from the journals of a man who explored the Pend Oreille Valley in 1889,” said Tommy Petrie, Pend Oreille County Sportsmen’s Club president.

The Hall Mountain bighorns were given supplemental feed near Sullivan Lake’s Noisy Creek Campground to boost the herd as well as to make it easier for researchers to capture animals for disease studies and relocation efforts.

The feeding was phased out from 2001 to 2003 after cougars began homing in on the feeding station, where the congregated bighorns were relatively easy prey.

“About 85 bighorns have been captured and taken away from Hall Mountain herd over the years,” said Petrie, who’s a volunteer for projects supporting the herd. “With about 20 in the herd now, we wonder how many rams can be removed before inbreeding becomes a problem here, too.”

Regular hunting has never been allowed on the Hall Mountain bighorns, although a statewide raffle tag gives a hunter the option to take a ram from any viable herd in the state. That tag has been used only once at Hall Mountain, Petrie said.

Disease issues that have stumped agency biologists and university researchers for decades continue to plague some Washington bighorn herds as well as wild sheep in Montana and Idaho.

Herds near Hells Canyon and the Yakima River Canyon have been hit hard since the 1990s by pneumonia outbreaks linked to possible contact with domestic animals.

The Tieton herd was wiped out by a disastrous outbreak, leaving wildlife managers no choice but euthanize more than 90 animals and finally to exterminate the last few members of the herd in 2013 to prevent a particularly virulent strain of pneumonia from spreading elsewhere.

The Hall Mountain herd, while disease-free, has struggled since winter feeding was discontinued. The area is short of bighorn-appropriate habitat, Harris said.

Washington has 16 bighorn herds totaling 1,250-1,530 animals, he said. The wild sheep are most prosperous where they have access to high, steep rocky terrain to escape from predators.

None of the Washington herds is west of the Cascades.

The forests that dominate the Sullivan Lake area aren’t prime bighorn habitat, Harris said. The heavy tree cover also has prevented accurate population counts.

The highest number tallied in recent years came last winter when helicopter surveys and trail cameras set out by wildlife enthusiasts found 21 bighorns including 11 rams, seven adult ewes and three lambs.

“That’s an unusual and disproportionately ram-weighted population structure,” Harris said. The herd likely interacts with bighorns in British Columbia, but neither country has focused research on the groups.

Petrie says there’s a lot of emotion and concern for the Hall Mountain sheep, which are a local tourist attraction. “We don’t feel there’s enough research on this herd to roll the dice on it,” he said.

Harris said the state would be lucky to capture any of the Hall Mountain rams, but if they do he feels moving them to the Blue Mountains area would be the best choice overall for the state.

“The Tucannon herd also numbers about 21 animals, but in contrast, it has only three adult rams, and these are known to be the same animals that have been in the herd for a few years,” Harris said.

That means the Tucannon lambs are likely to be closely related to one another, he said.

“We’ve been beating the bushes for options from nearby states,” he said, noting that disease issues elsewhere have stalled any transfers, so far.