TRAVERSE CITY, Mich. — A gray wolf relocated this fall from mainland Minnesota to Isle Royale National Park has died of unknown causes, officials said Tuesday, a minor setback in a multiyear plan to rebuild the predator species on the Lake Superior archipelago.
The 5-year-old male was among the first two wolves released at the park Sept. 26 . Staff biologists became concerned in late October when his radio tracking collar indicated he was no longer on the move, park spokeswoman Liz Valencia said.
A team traced the animal and found its carcass, which bore no bite marks or other signs that it had been killed by another wolf. It was taken to a federal wildlife health lab in Madison, Wisconsin, for a necropsy. Results are expected in December, Valencia said.
The fatality was the second since officials kicked off a plan to take 20 to 30 wolves to the park over the next several years to replenish its depleted population. A female died in a mainland holding facility in September.
"It's certainly not something you'd want to happen but it was not unexpected," Valencia said. "It's a high-risk operation."
Others are likely to die as the Isle Royale project continues, said Rolf Peterson, a Michigan Technological University biologist who studies the park's wolves and moose. Some won't make the transition to new habitat smoothly, while others will starve or be killed in territorial disputes with fellow wolves, he said.
Peterson said he hadn't seen the dead male's carcass but that hunger or stress were among possible factors.
It would be hard for a single wolf to bring down even a young moose, he said, although the island has plenty of beaver on which wolves can feed. Park officials shot six moose and spread some of the meat to give the new arrivals a temporary food supply, but it would have been picked over fairly quickly.
"Wolves live a very brutal life," Peterson said. "Their normal condition is extremely lean."
Isle Royale's wolf numbers averaged in the 20s for decades before plummeting more recently, largely because of inbreeding. Only two remained earlier this year.
Scientists say predators are needed to prevent the moose herd, which totals about 1,500, from becoming so large that the voracious animals overeat trees and shrubs.
The other wolf released Sept. 26 is doing well, as are two others that arrived in October, Valencia said. Counting the two aging survivors, the park now has five wolves.
The newcomers were trapped on the Grand Portage Band of Lake Superior Chippewa reservation in Minnesota. More are expected in January from the Canadian province of Ontario. Plans call for relocating additional wolves from Michigan's Upper Peninsula.