This map shows the path the female wolf took to reach the mainland/NPS

A wolf moved to Isle Royale National Park last fall in a bid to boost the island's predators took advantage of an ice bridge tying the island to the mainland and set off toward Minnesota where she had been captured.

“I was excited to see locations after not seeing anything for five days, but that excitement quickly gave way to disappointment as my eyes followed the track that led away from Isle Royale. I knew this could happen but of course you always hope for the best," Mark Romanski, the park's chief of resources, said Wednesday.

It was understood throughout the wolf relocation effort that there was a strong possibility of wolves trying to return to their home territories on the mainland, as wolves have been documented to return to their territory after long distance movements, natural or human-induced, a park release said.

"The early research on wolf translocation indicated that if you moved a wolf less than 80 miles it typically would try to return home, especially if it was a breeding animal," said Dave Mech, a U.S. Geological Survey wolf biologist and former member of the Isle Royal wolf research team. "So a Minnesota wolf trying to return is not surprising. However, we also found that if they were held in the release area for three to four weeks they generally stayed in the area. Since all of the new wolves were moved in the fall it will take time to tease out the behaviors related to translocation. 

"The Isle Royale wolf translocation is new territory in understanding wolf behaviors and will be ground–breaking with new information as it unfolds," he added.

The wolf turned up missing shortly after the recent partial government shutdown ended and researchers were able to head to the park to assess their condition. Romanski had been monitoring GPS data from each of the translocated wolves in preparation for the introduction of Canadian wolves to the island. He noted the wolves had been moving about the southwestern end of the park. However, no locations were reported for nearly five days, between January 27 and February 2. This can happen when a wolf is hunkered down in dense forest cover and there is no clear view for the collar to transmit data up to the satellites, park staff explained. Blinded by the poor satellite transmissions, the park needed aerial observations to help locate the translocated wolves. 

Michigan Technological University researchers arrived last Saturday and within hours of landing Rolf Peterson, principal investigator for MTU, and his contracted pilot, Don Murray of UpNorth Aerials, were in the air radio-tracking the translocated wolves.  After confirming the presence of two of the three collared wolves, the team directed their attention to a very static-filled signal radiating from off Isle Royale’s north shore towards Canada. 

“We followed the signal toward the north shore of the island and finally out over the open water of Lake Superior,” said Peterson. “A lead a half-mile wide had opened a few hours before, as the ice bridge was dislodged by a strong northeast wind. We flew out across the open lead and out over the ice pack then determined that the wolf’s signal was still to the north, straight to the mainland. We gave up further search because the weather was deteriorating and evening was approaching.”

Released at Isle Royale in October, this wolf left the park via ice bridge in January/NPS, Jim Peaco file

Immediately prior to twilight, the plane returned to Windigo on Isle Royale with Peterson suspecting a wolf had departed the island. He reported his findings to Romanski, and later that day satellite GPS data from the collar confirmed their suspicion. Romanski documented the departure from the island of F003, a female wolf translocated to the park in October 2018. The wolf left the island on January 31, headed north and then west to a location just north of the Pigeon River, on the border between Canada and northeastern Minnesota.

"Nature and the instincts of wildlife will always prevail in the wilderness of Isle Royale," said park Superintendent Phyllis Green. "When we made the decision to restore the predator-prey relationship, we knew we would have to respectfully work with whatever curves nature threw at us, whether it's adverse weather or wolves working out where they choose to fit on the landscape. We're going to continue the project for the next three years, a window we feel affords us the opportunity for successful restoration." 

The National Park Service continues to work with the Ontario Ministry of Natural Resources and Forestry to move wolves from Canada this winter. The recent polar vortex that created the ice bridge to the mainland also disrupted translocation efforts and forced the team to adjust their plans. Michigan Tech researchers plan to stay on Isle Royale to complete their annual survey efforts until March 4.