The winter study of the wolves and moose on Isle Royale is heading into its 59th year. The wolf-moose study is the longest running study of any predator and its prey in the world.
Scientists from Michigan Tech spend several weeks on the island in the middle of winter every year. They'll be heading back out soon.
At one point in the 1980s, there were 50 wolves on the island. Last year, the researchers found there are just two wolves left, and they’re in rough shape. These wolves are father and daughter – and also half-siblings because they share the same mother.
Rolf Peterson is a research professor at Michigan Tech who's been studying the wolves and moose on Isle Royale for 47 years. He says when he returned to the island this summer, those two wolves seemed to be surviving.
“As late as September, we had a visitor report of two wolves howling that seemed pretty reliable and I had them on camera in June, on a remote camera," he says. "No reproduction this year and that’s to be expected given their close relationship.”
Meanwhile, life is very good for the moose.
Last winter, the team estimated the moose population at 1,300.
“They’re not dying, that’s for sure. They’re reproducing very well, lots of calves and lots of twins," says Peterson.
He says he expects there could be 1,500 to 1,600 moose on the island now. So how long will it take before there are too many moose and they run out of food?
“It’ll creep up on everybody, including the moose. The moose as they age will become more vulnerable to starvation and malnutrition,” he says.
Last month, the National Park Service put out a proposal to bring new wolves to the island, and there are a few different ways they might do that.
“The plan they prefer is to introduce 20-30 wolves over a three to five year period, which is actually a pretty aggressive intervention," says Peterson. "And it recognizes and tries to remedy the two primary issues: inbreeding in wolves and lack of predation. So by putting a large number of wolves on the island they hope to maximize genetic diversity right at the outset and also get the number of wolves high enough so their predation will have some impact on moose.”
He says that plan should work just fine, although he says it's a "little bit experimental."
"But it’s worth a try and it does put a lot of wolves on the ground, and they will eat or die," he says. "But nobody really has done it that way before.”
Peterson says it could be a few years before any new wolves are introduced to Isle Royale. He says those new wolves would just become part of the study.
"We do know what happens when the predators are gone. So the predator-prey system that’s been the subject of the study for so long wouldn’t be just instantly re-established. But the adjustment, that would be a learning experience for everybody, I guess,” he says.
You can weigh in on the National Park Service's wolf proposal here.