After leaving Isle Royale on an ice bridge, wolf made epic journey
In late January 2019, during a bitterly cold winter spell, scientists flew to Isle Royale in Lake Superior to try to locate three wolves that had recently been relocated to the island, the first part of a landmark effort to restore the delicate balance between wolves and moose — their chief prey — in the remote national park.
Four wolves from the Grand Portage reservation on the far northeastern tip of Minnesota were trapped and moved to Isle Royale the previous fall. One died shortly thereafter. The other three survived, but scientists had lost track of them. The wolves’ GPS collars hadn’t transmitted any locations for five days.
After arriving on the island, the researchers quickly located two of the wolves, but couldn’t find the third. They picked up a static-filled signal out over the ice that had begun to break up on Lake Superior. But the weather worsened, and they had to turn around.
Later that day, they finally received satellite GPS data from the wolf’s collar, and it confirmed what they suspected— F003, a female wolf, had departed the island on January 31 on an ice bridge that had formed, connecting the island to the mainland. The wolf headed to a location just north of the Pigeon River, on the Canadian border, very near to the area where it had been captured about three months earlier.
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“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,” Dave Mech, a well-known wolf biologist with the U.S. Geological Survey, said at the time. “So a Minnesota wolf trying to return is not surprising.”
But Mech and others also knew that if a relocated wolf stayed in its new home for at least a month, then it generally stayed.
The researchers continued to monitor the movements of the two remaining wolves that had been relocated to Isle Royale, primarily to study their predation habits. But they also continued to track the whereabouts of wolf F003, because her GPS collar continued to send signals of her location every four hours.
And it turns out, she made quite the journey. A team of federal, tribal and university researchers recently published a study detailing the wolf’s travels after she left the island.
After spending about four weeks on the mainland near where she was born, the wolf spent a couple months looping around northeastern Minnesota, and then another couple months traveling far into Ontario.
“She covered over 385 straight-line kilometers [about 240 miles] from where she started her emigration when she hit the mainland to her furthestmost west location,” said Beth Orning, the study’s lead author, who at the time was with the SUNY College of Environmental Science and Forestry in New York.
“Movements like that are are pretty rare for wolves. Most of them settle within 55 kilometers of [where they were born],” she said. Previous research suggests only about 3 percent of wolves will travel so broadly, Orning said.
But wolf F003 wasn’t done. She traveled widely throughout Ontario before returning to the Grand Portage reservation in Minnesota for a month. Then she traveled back to Ontario, where she largely stayed through 2020, until she made a trip northwest of the city of Thunder Bay. That’s when her collar stopped transmitting.
While researchers will never know specifically what led this individual wolf to cross more than 15 miles of Lake Superior ice and embark on such a long journey, they “posit food stress, social competition, and lack of breeding opportunity, or a combination of these and other factors may have facilitated the long-distance emigration of this wolf from Isle Royale.”
On a species-wide level, Orning says it’s advantageous to have some animals willing to travel farther than others.
“Having some animals that move those greater distances are going to disperse genes much further into different parts of the population,” she says. “So having these occasional individuals that make these long-distance dispersals is a evolutionary biological strategy.”
While researchers will likely never know the fate of Wolf F003, they are still tracking the other wolves that were relocated to Isle Royale. 19 wolves from Minnesota, Michigan and Ontario were captured and brought to the park.
As of April 2020, researchers estimated there were 14 wolves on the island. Eight have died, but scientists believe at least two pups have been born.