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ESF Scientist Helps Locate Wolf That Died on Isle Royale
Dr. Jerry Belant, the Camp Fire Conservation Fund Professor at ESF, recently helped staff members from the National Park Service (NPS) locate the body of a wolf at Isle Royale National Park in Michigan, just a few weeks after it had been translocated to the park from Canada as part of an effort to bolster the area's declining wolf population.
In March, NPS personnel discovered the wolf's GPS collar was transmitting a mortality mode signal. The wolf, known to the scientists as W006M, was a black-coated male that had been released to the park in late February. NPS personnel, unable to access the island, had to wait until the park reopened for the 2019 season to investigate. The wolf was located in the middle of Siskiwit swamp, a large wetland complex at the southwest end of the island. Following coordinates from the GPS collar, Belant and NPS personnel traveled five miles into the swamp to recover the carcass and determine the cause of death. The GPS collar had quit transmitting two weeks earlier. Investigators found no apparent signs of injury or struggle; however, the carcass had deteriorated because of melting snow and wet conditions, making an accurate cause of death determination impossible.
Annual survival of wild wolves in the nearby Upper Peninsula of Michigan is approximately 75 percent.
"After translocation of 11 wolves this winter, it was a disappointment to learn of this mortality and even more frustrating that the carcass could not be accessed in a timely way for a detailed necropsy," said Mark Romanski, division chief of natural resources for the park. "A few weeks prior this male was traveling with one of the females translocated from Minnesota in October 2018. It would have been nice to see them stay together."
The new wolves are beginning to form loose associations with one another as seen by overlapping GPS coordinates at the same time and place. A female wolf, known as W001F, that translocated from Minnesota in September 2018 and two male wolves, identified as W007M and W013M, that moved from Michipicoten Island, Ontario, Canada, this winter have been traveling together since early April. "While GPS data indicate these three wolves have been together on numerous occasions, it's too early to tell whether we have a makings of a wolf pack," said Romanski, "but it is reassuring that we have wolves spending time together and feeding."
The NPS along with partners from ESF have initiated a study to look at summer predation and are using GPS locations to determine "clusters," a group of consecutive GPS locations within 50 meters (55 yards) of one another, for investigation as to whether wolves have made a kill, are scavenging or perhaps just resting. This data will help managers and scientists determine the impact of the wolf population on the island's moose population and document predation of other species such as beaver and, less often, snowshoe hare.
Akin to finding a needle in a haystack, field technicians searching two clusters each an area of nearly 0.8 hectares (two acres) discovered two probable snowshoe hare predation sites this past week; often all that remains at these sites are the feet, which wolves typically do not consume.
"We will continue to monitor the movements of wolves year round and use social network models to help determine the timing of pack formation and other aspects of wolf organization and predation on the island," Belant said.
This story was adapted from a press release from Isle Royale National Park.