BIG BOUNDARY LAKE
Jamie McLelland rolled the black tarp to the top of the metal gate, unlatched the chain and entered the animal pen.
With quiet steps on the forest floor, honed over hours upon hours of practice, McLelland stalked north along the perimeter of the paddock, a rifle slung over one shoulder.
He didn’t want to use the rifle. He’d had to use a shotgun once, last Saturday, on a black bear that somehow broke into the pen.
In the four years that the Yukon Environment department had been running a capture-release recovery program for the Chisana caribou herd in the territory’s southwest, a predator had never successfully invaded the 12-hectare holding area.
Grizzly bears would occasionally gather just beyond the electric wiring that surrounded the black tarp enclosure, like lunch-hour patrons waiting in line for a buffet they could smell, if not see.
If the grizzlies didn’t zap themselves on the electric fence, wildlife technicians who constantly monitor the trapped caribou, day and night for three months each spring, would scare them away by firing cracker shells.
The black bear McLelland shot was the first bear he had seen in the area in 2006.
How the bear made it into the pen is still a mystery. There were no detectable breaches in either fence, or burrows underneath.
But the bear made it in somehow, and wasted no time acquiring a taste for caribou calf that had never known the dangers of life in the wild.
The bear killed one calf, perhaps a month old. A medium-sized adult male, he ate the calf’s innards and left the rest.
The other caribou — 48 cows, 44 calves — scattered when the predator approached the feeding troughs.
Watchers in a tree blind notified McLelland of the bear’s presence. He had only one option — a regrettable one, in his opinion.
But after four seasons of painstaking effort to arrest the mysterious decline of the Chisana — and a $1-million investment from multiple governments, including Ottawa and Alaska — a single black bear couldn’t be allowed to wreck the project.
On Wednesday, like most days, the rifle hanging across McLelland’s back was a precaution rather than a necessity.
He suddenly paused in his quiet stride along the fence line ridge and put a hand to his ear. He took a few more paces and pointed downward, through the trees, into a dell below.
The caribou were gathered along a creek, sunning themselves and drinking — 92 animals, a calf for almost every cow.
Heads snapped up, sniffing, as the pack of human onlookers took positions with their cameras.
Though accustomed to such intrusions, the cows grew restless. The collective fight-or-flight instinct prevailed, and they moved south into a more wooded section of the enclosed forest that had been their home for three months, their calves at their heels.
The revolutionary idea of capturing pregnant cows in the spring and penning them during birthing was first hatched by Michelle Oakley, a regional biologist from Haines Junction and one of the chief architects of the Chisana project.
Back outside the pen, Oakley explained the strategy.
“The problem with this herd is neo-natal calf losses,” Oakley said as technicians began removing a portion of the fence line, to release all the animals back into the wild.
There are too many older animals and not enough young ones for the population to sustain itself, she said.
“Why are these calves dying? That’s what we need to figure out.”
The Yukon government has data from 1989 suggesting about 1,800 caribou in the herd, which winters in Alaska’s Wrangell/St. Elias National Park and Reserve and summers in the Yukon, just south of Beaver Creek.
Post-1989, for reasons unexplained, the calves started dying off.
David Dickson, an outfitter in the region, first noticed the Chisana population was simultaneously aging and shrinking.
Dickson raised the alarm and voluntarily quit hunting the herd in 1992. An international ban on hunting Chisana was instituted in 1994.
Though they hadn’t hunted the herd for a generation, the White River First Nation asked the Yukon government to step in.
“White River considers this land to be empty if there are no caribou in it,” said Oakley.
The Yukon counted the herd and reckoned there were between 300 and 350 animals.
At Oakley’s suggestion, Environment implemented a pilot project.
In March 2003, using helicopters and net guns, technicians captured 20 pregnant Chisana cows.
They bound the animals in “deer bags,” which are like straitjackets for ungulates.
They flew the caribou to a makeshift holding pen near the Alaska border, took blood and tooth samples and fed them for three months.
In June, they released 17 newborns along with the cows, all wearing radio collars.
Wolves killed one calf. The rest survived.
The following season the technicians started using sedatives on the animals. They captured the pregnant cows in the same fashion — dangling out the door of a low-flying helicopter and firing a net to entangle the fleeing beasts — then injected a sedative up the nose, to calm the caribou down.
The drugs helped. This year McLelland took an antler in the arm while wrestling a netted cow, “but it’s still way better for the animal,” he said.
The technicians released 35 calves in 2004 and 45 in 2005, said Oakley.
They repeated their 2005 success this year.
The project lost four calves this spring though — one to the bear, two were stillborn, and a sickly calf was “euthanized” after two weeks of struggling to survive.
Another calf managed to wriggle through the fence.
With surprising ease, the technicians identified its mother and released her. The pair took off into the wild.
The consensus is that, overall, the project has been a success.
The project has achieved an 80 per cent survival rate for calves, compared to 15 per cent in the wild.
Technicians estimate that, today, between 30 and 40 per cent of the herd’s calves were born in captivity.
“Seventy to 75 per cent of calves from the pen make it to adulthood,” said McLelland.
“The survival rate is very good with these calves.”
As the calves grow, their collars break and fall off, but there are still about 140 active collars among the herd, he said.
Oakley now believes the government’s earlier count of 300 animals was off. Environment estimates 725 caribou in the herd — considerably less than the 2,000 or so animals thriving in the 1980s, but not as drastic a loss as it seemed when the recovery program was initiated.
Nevertheless, something caused the decline.
It could have been the changing foliage. Twelve hundred years ago, Mount Churchill erupted, roughly 80 kilometres westward, raining ash across the Yukon all the way to the Northwest Territories border, said parks planner John Meikle.
The changes to the geography and vegetation of the Chisana range could have manifested over the centuries, resulting in a latent impact on the herd, he said.
Or it could have been the wolf kill.
For many years the Yukon and Alaska governments sanctioned a hunt, but banned it in the 1970s, said Oakley.
The Chisana herd might have swelled in the absence of predators, and the recovering wolf population might be bringing the caribou back into check.
The signs suggest predation as a primary cause of the Chisana decline, since the problem seems to be linked to calf mortality.
But Oakley doubts that predation tells the entire story.
There could be a disease issue, or a combination of climate factors that are causing the herd to fluctuate, she said.
“My hunch is that this is more than just a predation issue.
“There’s something wrong with these calves.”
David Johnny, the White River chief, suspects human causes.
Global issues, like climate change, or local ones, like jet planes passing overhead and dumping their fuel particulate on the land, could be contributing to the Chisana’s struggle, he said.
“Since we’re polluting the Earth, we need to give back something.
“That’s why White River stepped in.
“Even though we don’t use (the caribou) now, we will in the future.”
The causes of the Chisana’s decline may not be known, but that’s all the more reason to keep the research going, said Johnny.
“We need to really dig into it, instead of just scraping the top,” he said as a Super Cub airplane scouted the area, looking for predators.
“If there is a disease in there that is on the verge of being found, and we walk away from it, we jeopardize the whole thing.”
Johnny wants the capture-recovery program to continue for at least two more years, so there is some overlap of adult caribou born in captivity that rear calves of their own.
The program is groundbreaking, and is already serving as a research model for jurisdictions across North America that have concerns for species at risk, he said.
Indeed, the University of Calgary uses data from the Chisana project in some of its veterinary classes, said Oakley.
But the project has reached its conclusion, as far as the Yukon budget is concerned, she said.
“This is the end of funding for the captive-rearing project.
“Should we be spending more money on this, or should we take a step back and look for the root causes?
“There is still this fundamental question of why this neo-natal survival rate is just crashing.
“We’re going to get the team together and talk about it (in the fall).
As Oakley, McLelland and Johnny looked on, the caribou trotted towards the gap in their manmade environment, goaded by technicians into a zone that had been surrounded by black tarp, but was now open.
A single alpha female — number 21, by the label on her neck — led the herd right to where the fence line used to be.
Then she paused, uncertain.
She lifted her nose to the wind and stared at the forest vista that had been closed off by a black wall for several months.
The cow took a few tentative steps beyond the fence line, her calf in tow.
And then the caribou ran, followed by almost 100 others, over the hills and far away.
It was a perfect release, said Oakley.
“They’ve got to go do their caribou thing, and that’s good,” she said.
“Today is the end of a lot of things.”