Selkirk caribou Province of BCHere at Sightline, we’ve been tracking the ups and downs of the Selkirk Mountains caribou herd, a tiny population of the most endangered large mammal in North America. They would be outnumbered by the kids in two large kindergarten classes, or the baseball players suiting up for a major league game. The numbers are so low that each year biologists in planes or helicopters scan the mountains of Idaho, Washington, and southern British Columbia to try and count every single animal that’s still alive.

The mountain caribou face many threats—logging has transformed their habitat into prime deer country, which has in turn lured predators like mountain lions. Winter snowmobilers and backcountry skiers stress the animals at a time when they have little energy to spare. But BC recently introduced stronger habitat protections, and Idaho has limited motorized backcountry use. So you might expect to see caribou numbers tick upwards.

Not this year, at least.

In 2010, biologists counted 43 Selkirk caribou, 3 fewer than in the previous two years. But it’s too early to say whether that represents a one-year anomaly or a real decline. Because the snowpack was relatively low in the Selkirks this winter, a few animals might have been hanging out in lower elevation forests where it’s difficult to see and count them from the air, said Wayne Wakkinen, a senior wildlife research biologist with the Idaho Department of Fish and Game.

“It’s kind of a tough call on whether this is a real population decline that is the start of a trend or a one year blip,” Wakkinen said. “With a population as small as it is, we try to get a pretty darn good number…But did we miss a group of 3 or 4? To me, it’s something to be concerned about but not alarmed about.”

And here’s another unknown: no one can predict how the endangered Selkirk woodland caribou will fare if another animal extirpated in large parts of its historic range—the gray wolf—moves back into their territory.

  • In the last two or three years, wolves (likely moving south from BC or possibly east from Montana) have been documented on both the British Columbia and Idaho sides of the Selkirk Mountains near caribou recovery areas, Wakkinen said. That could be good—or bad—for caribou, depending on how things play out.

    If wolves get established, stick primarily to eating white-tailed deer, and run off the mountain lions that have been preying on the Selkirk herd, that would be good for the woodland caribou. Or wolves could might drive the mountain lions to higher elevations, even deeper into caribou strongholds. Or the wolves could start preying on the caribou themselves, as they have further north in British Columbia. And since wolves generally are trying to feed entire packs of animals—as opposed to more solitary mountain lions—they could wreak havoc on a small caribou herd in short order.

    As the chart below shows, the one thing we can say for sure is that this precarious population of caribou can hardly afford more trouble:

    Caribou historic abundance chart

    The bottom line? Maybe we’ll know more about where things are headed after next year’s population count. “This thing is so dynamic,” Wakkinen said. “It’s really impossible to say until you see what happens. There’s a lot of different ways it could go, and we don’t really know yet.”

    Notes on sources: Caribou numbers come from the 2010 Woodland Caribou Census: South Selkirk Mountains, produced by Idaho Fish and Game, BC Ministry of Environment, and Fish and Wildlife Compensation Program – Columbia Basin.

    Caribou photo: Ministry of Forests and Range, Province of British Columbia.