GPS collars inform Isle Royale wolf restoration and monitoring efforts

Copper Country

Figure 1. W012M from Michipicoten Island released on Isle Royale on 23 March 2019. Courtesy of IRNP.

HOUGHTON, Mich. (WJMN) – Initial results from collaborative efforts to restore the wolf population and predator-prey dynamics are in.

Personnel from the National Park Service (NPS), State University of New York College of Environmental Science and Forestry (SUNY ESF), Grand Portage Band of Lake Superior Chippewa, U.S. Department of Agriculture, Wildlife Services, and Michigan Technological University captured five wolves on Isle Royal over a two-week period in late April and early May to attach GPS radio collars for evaluating spatial distribution and habitat use, predation and social structure of this population.

The captures included a translocated male wolf originally caught on Michipicoten island, Ontario (W012M) and three males and a female all presumed to have been born on Isle Royale in 2020. The capture of the four unmarked wolves demonstrates reproduction and survival which are important metrics for the restoration effort.

“As batteries wear out on the GPS collars on wolves originally translocated to Isle Royale, we lose their signal. The capture of wolves this spring was critical for us to continue our long-term monitoring of this population, in part by placing new collars,” said Jerrold Belant, SUNY ESF professor and researcher on the project.  “Characterizing the activities of individual wolves in relation to pack formation, reproduction, and survival will greatly improve our ability to measure the success of this effort.” 

Wolf W012M was estimated to be two to four years old when he was captured on Michipicoten Island in March 2019. The wolf was in good condition in early May of 2021 and is now estimated between 4 to 6 years of age. He was caught in the same area where three of the unmarked wolves, two males and a female were captured and is presumed to be the breeding male of the pack pending confirmation from genetic analyses. The other young male was captured in a different area of the park.

Figure 2. The pack that W012M belongs to included nine wolves on 12 December 2020. Courtesy of IRNP.

GPS data from the wolves will be used to identify “clusters” or locations where the wolves have spent extended periods of time. The data will distinguish predation, rendezvous, rest and den site locations. Location information will allow researchers to quantify reproduction and recruitment of the population.

Researchers can visit identified den sites after the wolves have moved on and collect scat that will provide genetic evidence on the potential number of pups born as well as the ability to determine parentage and packmates. Scat collection at rendezvous sites and repeated systematic searches for scat on the park’s trails allows researchers to follow individual wolves through time and further estimate survival and reproduction.

“Like scientists all over the world, our restoration team adjusted to the impacts of the COVID-19 global pandemic,” said Mark Romanski, NPS biologist and project coordinator. “Winter capture operations were canceled twice, and the annual winter population count in 2021 was cancelled, so the NPS adapted. Once again, our partners stepped forward to help ensure that the effort to live capture and collar wolves this past spring was a success and carried out safely. The ability to document reproduction and recruitment is essential for evaluating the restoration program’s success, and GPS collars are one of the most important tools in our toolbox.”   

Figure 3. Movements of four collared wolves on Isle Royale during June 2021 and probable den site (black circle). Arrows indicate direction of wolf travel to and from den site. Courtesy of IRNP.

The NPS and its collaborators will continue to monitor this population of wolves and document ecosystem changes as they settle into the island environment. For further information on the population and ongoing research and monitoring concerning this ecological restoration project please visit the NPS website at Wolves – Isle Royale National Park (U.S. National Park Service) (nps.gov)

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