An iconic Pacific Northwest species’ declining numbers has resulted in its quiet withdrawal from its last remaining historical habitat in the United States.
According to researchers, the Selkirk herd of woodland caribou, which lingered as one of the most threatened species in the U.S. for decades, has all but disbanded. After a harsh winter that disrupted a last-ditch recovery effort, just three female caribou remain.
The last-remaining herd of woodland caribou in the U.S. ranged from north-eastern portions of Colville National Forest in Washington State and lower British Columbia. The herd struggled for years, challenged by everything from habitat loss and freeway development to predators and even snowmobiles in its south.
The antlers from one of the last South Selkirk mountain caribou were recovered after the animal was injured by a vehicle strike on Canada’s Highway 3, and subsequently killed by an unknown predator (bear or wolf). They are displayed in the Kalispel Tribe of Indians Dept. of Natural Resources office, The herd was stabilized at around 50 individuals for more than a decade, but declined sharply from 47 in 2008 to just 11 by 2017. As of spring 2018, only three caribou from the herd remain, all female.
In recent years, state, and federal agencies and their Canadian counterparts began working with the Kalispell Tribe of Indians and Kootenai Tribe of Idaho, and private organizations launched an ambitious plan they hoped would help the herd restore its rapidly diminishing numbers; building an enclosure to house pregnant female caribou each winter to protect them and their offspring from human harassment and predators, during the winter months.
Volunteers spent months collecting and drying hundreds of pounds of lichen, the caribou’s preferred winter food.
As winter approached in late 2017, they were ready.
And then, record-breaking snowfall buried the fence. The caribou left the pen, and rejoined their herd. Before the season, there were just nine caribou were counted in the preceding census. The following spring, surveyors found only three – all females. A bit later, they confirmed that none of the tree were pregnant.
The caribou herd’s ability to replace itself naturally was gone; and with it, the Selkirk herd’s future is in doubt.
“We mourned, we all had a period of grieving. We were distraught,” Ray Entz, Director of Wildlife and Terrestrial Resources for the Kalispel Tribe of Indians, said. But all is not lost, he said. “We see this as an opportunity to redouble our efforts, to get it right.”
The mountain-dwelling woodland caribou is not extinct. But the numbers don’t look good. A few dozen more herds exist, all in Canada. They too are in rapid decline; their total number is estimated at fewer than 1,400, down from 1,900 just ten years earlier.
Why did the caribou’s begin to disappear? Over-hunting in the early 20th century is believed to have caused steep losses. But habitat fragmentation from other human-influenced activities may have further complicated the species’ ability to recover.
As development, logging or fire broke up larger swaths of forest, deer populations may have grown – attracting predators and increasing their numbers, who found the caribou to be easy prey.
Mike Borysewicz, a wildlife biologist for the Colville National Forest, has worked on caribou protection and monitoring for years. The South Selkirk herd, the last remaining woodland mountain caribou in the U.S. which ranged in British Columbia and the forest’s Salmo Priest Wilderness, is now considered “functionally extinct” in the U.S. with just three female caribou remaining in the herd as of mid-2018. The caribou remain endangered in Canada, where about 1400 caribou are thought to remain.
On the Colville National Forest, forest rangers distributed pamphlets, advising snowmobilers to look out for caribou tracks when riding off-road to avoid stressing caribou and prompting them to run, or even to abandon a ridge entirely after repeated encounters.
The forest, especially the Salmo Priest Wilderness, was actually a sanctuary for the herd, Mike Borysewicz, a wildlife biologist for the Colville National Forest, said.
“Most of the habitat on the U.S. side is … at elevations above 4,000 feet, on wilderness or National Park land,” Borysewicz said. “Essentially, what that’s meant is that the timber stands that were suitable for caribou haven’t been disturbed.”
In Canada, British Columbia wildlife managers launched an aggressive lethal removal program to protect the South Selkirk, and other caribou herds, from wolves.
But the South Selkirk herd was especially vulnerable to losses. It’s range is separated from other herds; by roads, by development and logging. It’s own range is also divided, by Highway 3 – one of Canada’s busiest cross-continental highways.
In early 2009, when the herd’s numbers hovered around 45 animals, three caribou died in traffic collisions on the busy east-west route. Several more were killed in a single collision with a semi-truck.
When the herd’s numbers dwindled to less than two dozen, wildlife managers began discussing the possibility of augmenting the herd with caribou from other parts of Canada.
An earlier effort to relocate caribou from healthier herds to augment the South Selkirk population, shortly after the species was listed for U.S. Endangered Species Act protection in the 1980s, was not successful.
“We’ve learned a lot since then,” Borysewicz said.
Those earlier transplants were introduced to the Selkirk mountains via a “cold release” released into the herd’s traditional range. Without members of the herd on hand to lead them to forage, the newcomers wandered away from the protection of the herd – taking their potential contributions in numbers and reproductive potential with them.
Today, wildlife managers would conduct a “warm release” that introduces newcomers to the herd in a more controlled manner, giving them the opportunity to be fully integrated into the group before being released from, he said.
But first, the coalition of organizations working to save the herd had focused their attention the other side of the equation – stabilizing the number of pregnant females and calves.
In 2008, the Nature Conservancy of Canada acquired the Darkwoods Conservation Area, a wilderness reserve deep in the heart of the herd’s winter range.
The organization began working with natural resources managers for the Kalispel Tribe in Washington State and the Kootenai Tribe of Idaho to build a maternal pen for the herd.
“That’s kind of why we (the tribal agencies), are in the middle of this. It’s easier working across the international boundary,” Entz said. “It’s going to take all of us.
He and Bart George, the Kalispel Tribe’s lead wildlife biologist, helped supervise construction of a “maternal pen,” 19 acres of walled-off wilderness on the Nature Conservancy of Canada’s land.
The tactic has been used elsewhere to support declining caribou populations by protecting reproductively-active females and their young. Pregnant caribou and their newborns were especially likely to fall prey to predators, because the cows leave their herd until they’ve calved.
A USDA Forest Service regional cost-share grant helped pay for the pen’s construction.
Hundreds of volunteers worked with the Selkirk Conservation Alliance to collect and dry nearly 300 pounds of “Old Man’s Beard,” a soft, airy lichen resembling Spanish moss that makes up the caribou’s preferred winter diet.
In 2017, the first caribou were netted by helicopter and released into the pen for what was to be the first of a three-year trial.
Then, it snowed.
“We had double the average snowfall in that part of the Colville. You just can’t plan for that,” Borysewicz said.
First, the shelter provided to house guards who would watch over the penned cows, collapsed under the weight of the snow. The guards were forced to abandon their post for the season.
The snow kept falling.
It piled in drifts so tall the caribou, with their snowshoe-like hoofs, eventually would have needed only to step over the 15-foot tall fence to slip back into the forest.
No one knows what happened, after that.
Maybe animal predators, stressed by the deep snowfall, exacted taken an unusually high toll on the herd that year.
Accidents or poaching could have taken some members from the herd.
Or perhaps, the deep snows that typically offered the caribou their best protection from danger were what betrayed them, burying them in an avalanche, somewhere where their bones may never be found.
For the communities and agencies, organizations and individuals who had banded together to save the South Selkirk Herd was as devastating, if not entirely unexpected.
“They were an accessible and readily available food source when times were tough, and caribou sustained plenty of people in valley because they were readily available. Part of the problem we have now is they are so readily hunted, by predators and people,” Entz said.
Now, the herd’s future is uncertain.
It seems likely some caribou will eventually be relocated – either new animals will be brought to the Selkirk mountains and introduced to the remaining three members in hopes of reviving the herd, or the remaining Selkirk caribou will be joined with another struggling herd in hopes of bolstering its numbers.
A mountain woodland caribou bull. US Fish and Wildlife photo.
Biologists have fitted them with radio collars this spring to track their movements, and are hopeful the remaining caribou’s movements could lead them to an answer about what happened to the rest.
While the future for the South Selkirk herd is grim, those involved in the recovery attempt said their efforts were not wasted.
“The lichen will keep for a while, that effort is not a lost cause. Once it’s dried and stored, it has a long shelf life,” Mike Lithgow, Director of Information and Outreach for Kalispel Tribe’s Dept. of Natural Resources, said.
With recovery, there’s hope that one day, caribou will once again venture south to the Colville National Forest and the Salmo Priest Wilderness as long as the habitat remains in place to receive them.
“This is not the end, it’s the beginning of a new fight,” he said.
Entz said he’s more than more than hopeful there’s still a future for the mountain caribou, whether in the South Selkirk mountains or beyond them.
“We aren’t going quietly into the night. We’re going down fighting,” he said “They took care of the tribe when it needed them. Now it’s our turn to take care of them.”
Source information: Catherine “Cat” Caruso is the strategic communication lead for the USDA Forest Service – Pacific Northwest Region’s Office of Communications and Community Engagement, and edits the “Your Northwest Forests” blog. You can reach her at firstname.lastname@example.org.