Six caribou in North Idaho and Washington – the last in the contiguous U.S. – will be relocated to Canada

Caribou, the Grey Ghosts of Idaho and Washington’s forests, will no longer roam the Lower 48.

After decades of work reintroducing the large ungulates into Idaho and Washington, Canadian wildlife officials decided to relocate the six remaining survivors who still occasionally enter the United States farther north into Canada.

There, Canadian biologists hope to breed the animals in captivity at a pen north of Revelstoke, British Columbia, deep in the Canadian brush, the Canadian Broadcasting Corporation reported Friday.

Bart George, a wildlife biologist for the Kalispel Tribe, hopes the breeding project is successful and that the caribou population grows to a point where it could “spill over into the U.S.”

In 2009, George said the South Selkirk caribou herd had 46 animals and was “climbing at a pretty good rate every year.”

But wolves started to filter onto the landscape about that time, George said.

“That’s been our primary source of mortality that we’ve known about,” George said.

Logging roads and increased snowmobiling access also played a role . But in terms of direct mortality, cougars and wolves were the primary culprits.

“Predation is obviously the No. 1 factor,” George said. “That was kind of the straw that broke the camel’s back at this point. All those other issues are concerns, but we don’t really understand how snowmobiling would affect the animals in the long term, other than we know it disrupts animals in the winter.”

He added, “Of the six collared animals that we collared in 2013, two were killed by wolves, one killed by cougars and one by an unknown mortality.”

In April, an aerial survey of the South Selkirk Mountain caribou herd found only three surviving members, all female. Over the summer one of those animals was killed by a cougar, George said.

Biologists and managers have known the animals were in trouble since 2012, George said. However, little was done.

“We really didn’t mobilize until it was too late,” he said.

Other herds in the range have “blinked out” in recent years. Full-scale recovery efforts began only recently, with Canada starting to control its wolf population in 2014 and maternal pen projects and population augmentation efforts starting only a year ago.

Canadian wildlife agencies have removed about 20 wolves since 2014.

Deep snow delayed the Kalispel Tribe’s maternal pen project and the enclosure was never used.

“We could potentially use that site in the future as a release site,” George said.

Although mountain caribou were listed as an endangered species in the U.S. in 1983, the U.S. Fish and Wildlife Service and the states of Washington and Idaho are not actively involved in the maternal pen project or controlling the caribou predators even though the caribou range extended south into Idaho and Washington.

“This is what extinction looks like, and it must be a wake-up call for wildlife and habitat managers in both Canada and the United States,” said Joe Scott, Conservation Northwest’s international programs director, in a news release. “While it comes as no surprise given the long decline of the only caribou herds that still roamed into northeast Washington and northern Idaho, today’s news marks the tragic end of an era.”

The South Selkirk caribou herd was the only one living in both the United States and Canada. It ranged through the high country along the crest of the Selkirk Mountains near the international border. The remaining 14 or so herds are all in Canada. It’s estimated that fewer than 1,400 mountain caribou are left in North America.

Known as Grey Ghosts because of how rarely they are seen, the South Selkirk caribou differ from caribou that wander the tundra farther north. These caribou use their wide feet to stand on top of deep snow and eat lichen that grows high in old-growth forests.

The mountain caribou have struggled as old growth forests have been thinned by logging and other industrial activities, George said. With thinner forests, the caribou have become more susceptible to predation.

Thinned forests have led to other problems, including vehicle strikes on Highway 3 in British Columbia.

The U.S. Fish and Wildlife Service wrote its first recovery plan for mountain caribou in the early 1980s and it was reworked in 1994. Working with Canadian agencies and First Nations, caribou from other regions were trapped and released in the area with some positive results.

But those positive results didn’t last, and, despite the Kalispel Tribe’s efforts, starting in 2012 the population has only declined.

“We talked about it, and we did a bunch of hand-wringing for the next six years until we ended up this position,” George said.

UPDATE Nov. 9: This story has been updated to clarify that the South Selkirk herd spends time in both the U.S. and Canada.