Images taken in late September 2019 from a remote camera show two pups likely born to wolf 014F in spring 2019/NPS, SUNY-ESF
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.
Comments
While it appears to have been successful I don't understand why they would relocate a wolf that was in poor physical condition. Maybe that accounts for a few (or was it only one) of the other deaths early on? I also appreciate the honesty in reporting the wildly different moose estimates, both using sound scientific methods I would assume.
Although Isle Royale is more than twice the size of Michipicoten Island, both of them are actually very small and, in the past, only the formation of winter ice bridges prevented inbreeding in the populations of larger animals on either island. Although researchers had been trying to continue using Michipicoten to study population dynamics and predator interactions in rare Woodland Caribou, the small size of the island, changes in the climate, the end of reliable winter ice bridges, and excessive and increasing human recreational presence in summer all contributed to a steady erosion of the conditions supporting Caribou and their population on Michipicoten, which, combined with the increasing importance of the few Woodland Caribou that remained, resulted in a decision to end that research effort and relocate all Caribou remaining on Michipicoten. With no Caribou, the remaining wolves on Michipicoten would have no suitable prey; so, they were all also removed, in their case for transplant to Isle Royale, which would have been logical because they were already accustomed to hunting large prey on a densely vegetated island. That's how 014F got relocated to Isle Royale despite already being both pregnant and in poor condition.
Wolves are highly social, highly dominant, and fiercely competitive animals. Even in Yellowstone, which is a much larger, diverse, and prey rich environment, and even today, twenty five years after reintroduction there, close to three quarters of all wolves still die in territorial or other dominance related warfare. Transplanting wolves, including the already pregnant 014F, from one environment into a new one, from Michipicoten to Isle Royale, was always going to result in an especially fierce and even fatal "sorting out" period at first. As Mark Romanski is quoted in the article, "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... 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." So, when you look at the strategic picture, transplanting an already pregnant 014F may have been a surprisingly fortuitous choice and her genetics and those of her pups may prove especially valuable in the future.
When moose numbers are in balance with available forage, Isle Royale is densely forested and, although rising moose numbers adversely effected the vegetation, some areas of dense forest remain. However, with the rise of moose numbers followed by the reintroduction of wolves, both the condition of the environment, moose numbers, and wolf numbers were all always expected to fluctuate relatively widely at first. Again, knowledgeable observers always expected an especially fierce and even fatal "sorting out" period at first. Counting moose in dense, multi-layered, willow and taller evergreens is always difficult, but made even more difficult when dense, multi-layered, willow and taller evergreens are combined with rapid fluctuations in numbers due to the presence of newly arrived predators, especially wolves. The same thing happened in Yellowstone. There were rapid and extreme fluctuations at first, leading to the average relative stability of the past decade.