So far four grey wolves have been transported to Isle Royale by the National Park Service (NPS), bringing the total to six.
It’s all part of a plan to restore the ecology of Isle Royale, home to approximately 1,600 moose, and expand the genetic diversity of the wolves.
The National Park Service is proposing to introduce 20 to 30 wolves over the next three years.
Before the transfer, there were two aging wolves on the 45-mile-long, 143,000-acre island, a male, and female, likely a father and daughter who can’t mate and are suffering from genetic abnormalities.
“We have some opportunities to work with Canada and may bring some more wolves here in the winter, but we’re pretty much done bringing wolves here this fall,” said Isle Royale Superintendent Phyllis Green.
The male and three females were captured in the Grand Portage Band of Lake Superior Chippewa forest, checked by biologists, sedated, and transferred to the island.
A fifth wolf, a female, died after being sedated. Her body was taken to the University of Minnesota where a necropsy was performed to determine cause of death. Green said researchers found the wolf had been given too much sedative, which caused the wolf ’s heart to fail.
“They (veterinarians) couldn’t find any abnormalities with the wolf. Nothing that would cause it to die,” she said, adding this is similar to what happens to a low percentage of pets that are sedated before surgery.
Once on the island the wolves, which had been radio collared, spread out. Each found moose meat that had been left for them.
“We wanted to give them an initial burst of calories and energy,” said Green. “When they were captured, no one knew when the last time was that they had eaten.”
When asked where the moose meat had come from, Green replied, “We chose to harvest them from the island. Six moose, three bulls, a cow and two calves were killed.
“We contracted USDA sharp shooters from Michigan and Minnesota who are very professional in what they do. We also brought in two people from Grand Portage to call the moose in.”
Also, said Green, “We didn’t want to bring moose meat from the mainland to eliminate the chance of transporting disease here.”
A side benefit for researchers was to perform necropsies on the moose before they became wolf food.
“We haven’t done any parasite or necropsy on Isle Royale moose for over 30 years. We have found moose killed by wolves and studied them but often their organs were missing or the carcass was in bad shape. This will help us know what is going on with the health of the moose on the island.”
Six wolves, none in packs, can’t reasonably hunt and take down a moose, said Green, adding the park isn’t going to kill any more moose to feed to the wolves. “But there is an abundance of beaver on the island, so they can hunt and have plenty to eat.”
Plans were to bring some more wolves from Michigan this fall, “But the weather shut us down,” Green said.
If a deal can’t be reached with Canada this winter to bring some more wolves to the island, Green said the plan is to begin wolf capture and transport in the spring from a variety of places.
As for any chance of pups to be born in the spring, the new, healthy male and one female came close for a short time, but there wasn’t any spark of romance and the two haven’t been near each other since the first encounter, Green said.
Will the new wolves make it through the winter, she was asked.
“I’m concerned that the public understand that there is a 30 percent annual mortality rate for wolves. This is the normal checks and balances in the wild. Alphas tend to live 7-8 years while subordinates live 3-5 years.”
Before making its decision to add wolves, the NPS spent several years looking at a variety of alternatives for the management of moose, wolves, and vegetation on the island. The moose-wolf-vegetation food web is tightly coupled, and the park’s final plan addresses those relationships.
Climate change was also factored into the NPS decision.
In the past, wolves would come from the mainland across winter ice, but the lake only freezes over every 15 years or so today, leaving less chance for new genes to be reintroduced to the breeding pool.
Dr. Rolf Peterson, a wildlife ecologist who spent more than 40 years on the Michigan Tech predator/prey study of the moose and wolves on Isle Royale, and his colleague, Dr. John Vucetich, an ecologist from Michigan Technological University, first began pressing the NPS to bring more wolves to the island in 2014.
In 2014, Peterson told the Cook County News-Herald, “Based on history, two dozen wolves corresponds to two or three packs.”
At that time there were nine wolves left, but they suffered from physical abnormalities associated with inbreeding, and as the two Michigan Tech researchers predicted, the pack kept dwindling until there were only two left.
Leave a Reply