ISLE ROYALE, MI - The wolf relocation project playing out on Michigan’s remote Isle Royale just got a heavy new dose of testosterone.

Four new Canadian wolves - three males that all tip the scales at around 90 pounds and one smaller female - have all been released on the island in Lake Superior in the last week, according to the National Park Service.

According to the data collected, one of the male wolves weighed in at 92 pounds. Another was an alpha male from his Canadian pack.

The four new wolves join the island’s two older wolves - a male and female - and two newer female wolves from Minnesota who were relocated to Isle Royale last fall. The relocation program designed to bolster the number of predators on an island teeming with more than 1,500 leaf-eating moose is expected to bring in up to 30 new wolves in the next few years.

The Canadian wolves were expected to be trapped and relocated earlier this winter, but severe weather hampered those efforts.

“During a narrow weather window between storms last week, Ontario Ministry of Natural Resources and Forestry (OMNRF) successfully transferred four wolves to Isle Royale National Park," park staff said. "... Two mainland wolves, one female and one male from the same pack and both with a black coat color variation, were captured on crown land near Wawa, Ontario, and transferred to Isle Royale. Weather cleared long enough on Thursday to provide an opportunity to access Michipicoten Island Provincial Park, where two males were captured.”

Aircraft were used to identify and capture all of the wolves. Two national park veterinarians and one from Ontario also were on hand to supervise the transfers and check the health of the wolves.

“All four wolves were evaluated based on expectations for winter body conditions and deemed healthy enough for transfer and release.”

Here’s a brief rundown on the new Canadian wolves:

First wolf: This 65-pound female arrived at Isle Royale last Tuesday.

Second wolf: On Wednesday, the team captured a large 92-pound male from the same pack. He was held for evaluation and transported to Isle Royale and released on Thursday.

Third and fourth wolves: “Clear skies Thursday finally allowed OMNRF to reach Michipicoten Island Provincial Park. While there, they captured two male wolves, one at the very end of the day as operations were winding down. The first was delivered directly to Isle Royale and released in the late evening hours under clear starry skies on Thursday. The team also captured the alpha male of the Michipicoten Island pack. He was transported and released on Isle Royale Friday.”

National Park staff said they appreciate the project team’s resilience to make the captures and transfers, despite all the recent hurdles. These have included not only a U.S. government shutdown, but a polar vortex and some airplane logistics issues. The planes used in this effort are ones typically used for firefighting by the Ontario group.

“I am even more blown away by the resilience of these wolves who within hours after undergoing capture and handling and arriving on Isle Royale, immediately got on the trail of their pack mates," said Mark Romanski, division chief of Natural Resources for Isle Royale National Park and project manager for the reintroduction efforts. "These large males, all around 90 lbs., will almost certainly know what to do when they encounter a moose.”

These large-muscled, brawny Canadian wolves are thought to be just what the island needs to reboot its predator DNA, researchers have said.

“To see these wolves disappear into the forests of Isle Royale and to have an opportunity to start a new generation of wolves on the island fulfilled a major objective in the first year of reestablishing the population,” Park Superintendent Phyllis Green said.

There have been some issues with earlier wolf transports, with three wolves lost. One male was relocated onto Isle Royale, but was found dead there weeks later. One female died after being caught, before she could be released on the island. Another female wolf took advantage of an ice bridge that formed between Isle Royale and Canada in late January, and walked back to the mainland.