The transfer of up to six wolves from a northern Ontario island where they were starving to the U.S. is getting underway following a weeks-long delay caused by the federal government shutdown south of the border.

The small pack, including the alpha male and female, will be moved from Michipicoten Island to Isle Royale National Park, on the U.S. side of Lake Superior, where American officials hope the wolves will help keep the moose population in check.

"We need to get these wolves off the island, otherwise they'll die," said Aaron Bumstead, director of lands and economic development with Michipicoten First Nation who is co-ordinating the move with the province's Ministry of Natural Resources and Forestry.

Last year, the province and the First Nation used several helicopters to move a total of 15 caribou -- a threatened species in Ontario -- off Michipicoten Island. Nine of the animals were transferred to the Slate Islands, and the other six to Caribou Island.

They were the last remaining caribou from a once-thriving herd on Michipicoten Island that started with just eight caribou in 1982 and grew to more than 700 by 2013, when four wolves reached the island after making the 15-kilometre trek across an ice bridge that formed on the lake.

There they found a bounty of caribou to feast on. But as the small pack grew to more than a dozen wolves in the following years, their food source -- the caribou -- all but disappeared. Now the wolves themselves are in danger, said Bumstead.

"We've been asking (the ministry) for a plan to remove the wolves from the island since last year," Bumstead said. "And there still is no plan to remove the ones that don't get moved to Isle Royale."

A spokeswoman for the Ministry of Natural Resources said she wouldn't comment on the wolves' transfer until the animals were captured and transferred to the U.S.

Bumstead said efforts to capture the wolves on Michipicoten Island were unsuccessful Wednesday. The two wolves they saw wouldn't come out from under cover, he said, so they'll try again Thursday.

American officials and researchers with Isle Royale are anxious to receive the Canadian wolves because it will help save the park's current pack, which dwindled this fall to just a non-breeding father-daughter pair.

The move was slated to occur in early January, but that was shelved because of the U.S. federal government shutdown, said Isle Royale National Park superintendent Phyllis Green.

"The Canadian wolves are robust, large and definitely know how to hunt ungulates since they took that caribou herd down to nothing," Green said.

There is an overabundance of moose on Isle Royale, and without enough wolves to keep their population in check their numbers will continue to grow, said Rolf Peterson, a research professor at Michigan Technological University who has been studying the wolves and moose on the island for the past 48 years.

His research -- the world's longest running predator-prey study -- was also threatened by the U.S. government shutdown. On Friday, just hours before U.S. President Donald Trump temporarily ended the government shutdown, the Isle Royale National Park had secured funding from a non-profit organization to go ahead with its part in the wolves' transfer from Canada. The funding also allowed it to open the park to researchers to continue the predator-prey study.

"The shutdown jeopardized the integrity of the data and of the entire study itself," said Peterson, who plans to return to the park as soon as the Canadian wolves are moved.

"These large-bodied Canadian wolves are incredibly important," he said. "They can help save both the wolf pack and the balsam fir."

The moose on the island, with a population of about 1,600, have decimated the balsam fir trees on the island.

Twenty-two years ago, a lone wolf, likely from Canada, made its way on an ice bridge onto Isle Royale, Peterson said, and was a wildly successful mate with offspring in every pack and eventually his genes made their way into every single younger generation wolf on the island.

"Then the kill rate of moose by wolves reached a level we hadn't ever seen before in 50 years. They were killing 20 per cent of the moose every year, which had implications for the forest," Peterson said.

"We saw forest regeneration we had never seen before."

But that wolf, dubbed the "Old Grey Guy," Green said, was so successful that inbreeding became very severe. Eventually the wolf population crashed and bottomed out at two, which is when the park decided it needed outside help. Four wolves were brought in from Minnesota in the fall, but one died of pneumonia a month later.

Green said they knew about the issues facing the wolves on Michipicoten Island and Michigan's governor at the time, Rick Snyder, reached out to Ontario Premier Doug Ford to ask for "an infusion of Canadian wolves."

Ford agreed.

"Let's hope everything goes well with the move," Bumstead said.