By NPT Staff
An unknown number of pups has been born to wolves transported to Isle Royale National Park in a bid to regain a healthy prey-predator ratio.
Park staff on Monday announced that tracking data suggest pups were born on the island park in Lake Superior in both 2019 and 2020.
GPS collar data from female wolf 014F, translocated from Michipicoten Island, Ontario, in March 2019, suggested denning in spring 2019, a park release said. This wolf established several rendezvous sites that spring and summer. Images from a remote camera taken on September 29, 2019, reveal that wolf 014F likely gave birth to at least two pups. In addition, researchers at Michigan Technological University (MTU) observed a likely pup in February 2020, the release added.
Genetic analyses of scats collected at one of the rendezvous sites will be conducted, and if pups are confirmed, it suggests wolf 014F likely was pregnant before translocation to Isle Royale, said the release.
Mark Romanski, the park’s wildlife biologist and wolf introduction program coordinator, said during a phone call Monday that only two pups in a litter normally would be considered low, if that’s all there were, but wolf 014F was not in the best physical condition for a pregnancy.
“014F was living on Michipicoten Island, where their primary prey, caribou, had virtually been extirpated and the government there removed the 15 remaining caribou, a protected species in Ontario,” said Romanski. “This wolf would have been in poor physical condition due to nutritional stress.
“In addition to the stress of translocation, I think it is remarkable that she was able to give birth and rear new pups in her new environment during the summer of 2019,” he added. “This is also in consideration of 16 other wolves on the island also trying to eek out a living, so potential for conflict would have been high.”
Analyses of GPS location data for wolf reproduction in 2020 supported denning activity in early April for female wolf 001F. This wolf, captured on the Grand Portage Indian Reservation in northeastern Minnesota, was the first wolf translocated to Isle Royale, back in September 2018. Her GPS collar attempted to obtain locations during early April 2020 but failed, indicating the collar was underground or in dense vegetation.
Investigations of the den site in June 2020, after wolves had moved away, resulted in biologists collecting 18 pup-sized scats. Genetic analysis conducted on these scats will help to determine the minimum number of pups born to wolf 001F.
Additionally, in July 2020, researchers obtained images from a remote camera of a single pup. Only a few hours later, an image of a single adult wolf at that same site was identified. Based on GPS data, this pup was born to female wolf 014F or 015F. Visitors reported pup-sized tracks near this same location in early August and Michigan Tech researchers collected 13 pup-sized scats nearby that will assist in determining the minimum number of pups in this litter.
“We can estimate the minimum number of pups born annually from scats collected at den and rendezvous sites, as well as monitor the genetic health of the population through time,” said Romanski.
Biologists had hoped to have had the results of the genetic testing by now, but the lab at Michigan Tech was converted for use with Covid-19 testing earlier this summer and just recently was able to return to the scat testing, the park biologist said.
“Documenting reproduction is critical to the success of any introduction effort. In contrast to 2019 where female wolf 014F was likely pregnant before translocation, the breeding and rearing of two litters of pups this spring was a major step toward their recovery,” said Dr. Jerry Belant, a State University of New York-ESF professor aiding the National Park Service on the wolf recovery program at the park. “We will continue to evaluate reproduction and recruitment of Isle Royale’s wolves using multiple lines of evidence including GPS collar data, remote cameras, DNA from wolf scats, and observations.”
Isle Royale wolves had been in decline for more than a decade, as chronic inbreeding impacted their health. There was hope that “ice bridges” that formed between the Lake Superior island and the Canadian mainland during the winter of 2013-14 would enable wolves to arrive from Canada with new genes. But no wolves reached the island, while one female left and was killed by a gunshot wound in February 2014 near Grand Portage National Monument.
Under a plan adopted in 2018, up to 30 wolves were to be set free at Isle Royale through 2021 in a bid to build genetic diversity into the park’s wolf packs. The Park Service and research partners estimated as many as 14 wolves were present on Isle Royale as of April 2020. Eight wolves died with the most common cause of mortality intraspecific aggression.
Exactly how many moose are on the island has been difficult to ascertain. In 2018 there were an estimated 1,500. Since then the Park Service and Michigan Tech researchers have used different approaches to estimating the moose population. Currently, the number ranges from about 580 to perhaps 1,800, said Romanski.
Whether any more wolves will be brought to Isle Royale remains to be seen.
“We are grateful to all our partners who worked tirelessly to support this historic restoration effort and we look forward to continuing our numerous collaborations that are helping to ensure we meet our objectives for restoring this apex predator to the Isle Royale ecosystem. We will now evaluate the program’s efforts to date to determine whether further translocations are warranted,” said Isle Royale Superintendent Denice Swanke.