Isle Royale National Park
Release Date: September 14, 2020
Liz Valencia, 906-483-7721,
Mark Romanski, 906-483-8860,


Wolf Pups Born on Isle Royale!
HOUGHTON, MICH – Isle Royale National Park and State University of New York-College of Environmental Sciences and Forestry (SUNY-ESF) have documented reproduction for wolves introduced to Isle Royale in 2018 and 2019, a key element of the National Park Service wolf introduction program’s success, GPS collar data and images from remote cameras suggest pups were born in 2019 and 2020. An exact number of pups is yet to be determined.

GPS collar data from female wolf 014F, translocated from Michipicoten Island, Ontario, in March 2019 suggested denning in spring 2019. 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,

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.

We have no other evidence that reproduction occurred in 2019.

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 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 MTU researchers collected 13 pup-sized scats nearby which 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 Mark Romanski, NPS biologist and wolf introduction program coordinator at the park.

“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.

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.” noted Dr. Jerry Belant, SUNY- ESF professor assisting the NPS with characterizing the wolf introduction program. Continuing to track this population closely will allow the NPS and its collaborators to evaluate the long-term success of the introduction and how wolves impact the ecosystem.

By 2018, with the wolf population at Isle Royale down to only 2, the National Park Service (NPS) and partners initiated an introduction, releasing 19 wolves at Isle Royale National Park from

September 2018 through September 2019. Today, the NPS and research collaborator, SUNY- ESF released a summary report of the introduction effort so far,

Using location data retrieved from global positioning system (GPS) collars, scientists

monitored important aspects of wolf ecology, such as social organization, summer predation, mortality, and reproduction to determine the success of the project.

The NPS and research partners estimated as many as 14 wolves were present on Isle Royale as of April 2020.

“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 Superintendent Denice Swanke, Isle Royale National Park.

To learn more about Isle Royale’s wolves and the introduction efforts, you can watch CuriosityStream’s original film Breakthrough: Return of the Wolves, produced in partnership with the National Parks of Lake Superior Foundation and read the recently published summary report at

About the National Park Service. More than 20,000 National Park Service employees care for the 417 parks in the National Park System and work with communities

across the nation to help preserve local history and create close-to-home recreational opportunities. Visit us at, on



and YouTube

Liz Valencia
Manager, Interpretation and Cultural Resources Division
Isle Royale National Park
800 E. Lakeshore Drive
Houghton, MI 49931

From the Great Lakes Echo:

When L. David Mech arrived at Isle Royale in 1959, he had no idea he would pioneer the nation’s longest-running prey-predator study, one that would become a model for wildlife biologists around the world.

Nor did he likely expect to eat beaver brains or loon there.

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From the Washington Times and the Associated Press:

LANSING, Mich. (AP) – Some Michigan lawmakers believe the federal government should open Isle Royale National Park to moose hunters. reports that the House Natural Resources Committee heard testimony last week on a resolution supporting a limited moose hunt on the Lake Superior island. A vote could come at the next meeting.

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HOUGHTON, Mich. — The oldest gray wolf at Isle Royale National Park has been killed — apparently by newcomers to the Lake Superior island chain, officials said Friday.

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Island life isn’t for everyone, nor, it seems, for every wolf.

One year into a federal effort to restock the wolf population in Isle Royale National Park in Michigan’s Lake Superior, a pack of eight relocated from a nearby island appears to be thriving, while four of 11 wolves brought from the mainland have died. Another wolf voluntarily departed last winter, returning to Minnesota over an ice bridge.

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Isle Royale National Park PRESS RELEASE

Release Date: December 20, 2019
Liz Valencia, 906-487-7153,
Mark Romanski, 906-487-7154,

Group Formation of New Isle Royale Wolves Leads to Territorial Aggression

HOUGHTON, MICH – The National Park Service (NPS) and research partners from the State University of New York – College of Environmental Science and Forestry (SUNY-ESF) are using data from GPS collars on introduced wolves to monitor associations between individuals and identify possible pack formation. As researchers and NPS staff anticipated, new wolves immediately began interacting with each other. Researchers confirmed introduced wolves were feeding, traveling, sleeping in proximity to each other, and forming groups.

A wolf ‘group’ is characterized by two or more wolves traveling and feeding together. Wolf groups are further defined as a ‘pack’ if groups of two or more wolves are traveling together and/or defending a territory, and if a breeding pair reproduces.  Individual preferences for mating and group or pack formation can be quite variable for a social animal like the wolf. Mate selection and pair bond formation can occur at any time, but wolves only breed and produce pups once per year. Consequently, pack formation can take time. Based on these definitions, there are currently no wolf packs on Isle Royale.

GPS collar data shows three wolves, 1 female and 2 males, have been traveling, feeding, and bedding together since March, 2019 (W001F, W007M, and W013M).  This is the first wolf group to form and remain associated since introduction efforts began. Additionally, two male wolves shared bed sites and carcasses over the summer with several different female wolves, but their associations lack consistency and are currently not defined as wolf groups. Two female wolves shared bed site areas over the summer (July), but are also not considered a group.  Loose associations are common when smaller prey items like moose calves, beaver and snowshoe hare are abundant on the landscape. These animals are easy prey for a single wolf.

Dr. Jerry Belant, Campfire Conservation Fund Professor at SUNY-ESF and project collaborator added “Wolves are a highly social species and we continue to monitor their movements to document groups, and ultimately pack formations as demonstrated by reproduction.  We developed a public online tool, based on these analyses to understand potential associations among these wolves and the areas they occupy.”

Researchers monitoring the GPS collar signals identified two wolf mortality events this fall.  In September, researchers and NPS staff detected a mortality signal and recovered the remains of female W004F. Field evidence and subsequent necropsy at the U.S. Geological Survey National Wildlife Health Center in Madison, WI, determined W004F died from wounds caused by another wolf or wolves. In October just prior to island closing, NPS staff came across the remains of male wolf, M183, one of the two remaining uncollared resident wolves inhabiting Isle Royale prior to introduction efforts. Necropsy revealed that M183 had also been killed by another wolf or wolves. These events are not uncommon as wolves defend and establish their territories and social hierarchy. With many wolves on the island sorting out their relationships with one another, the dynamic nature of wolf social organization, territoriality, and wolf-on-wolf aggression during group and pack formation is not unexpected.

“With the death of the island-born male, travel patterns of the remaining wolves are likely to change significantly, and probably dependent on whether or not the island-born female is still alive, whether she is territorial and how she gets along with the newcomers, both males and females.  She is the final native wolf, never radio-collared, and searching for her will be a priority during the upcoming winter study.” commented Rolf Peterson, a research professor at Michigan Technological University and long-time wolf and moose investigator on Isle Royale.

Summer wolf location cluster investigations documented 122 instances of two or more wolves with overlapping space use. Twenty-nine cases (23.8%) of space use overlap were associated with prey remains and feeding behavior, 68% were associated with bed sites, and wolf use for the remaining 7.4% of sites was unknown or could not be determined.

Researchers continue to monitor location data weekly for evidence the three newest wolves, released on the island in September, are adjusting to their new homes, interacting and forming associations. These wolves are interacting with each other (W017M and W018F were traveling together in late November) and with the wolves released last spring (W018F and W016M traveled together in early November).

NPS and its collaborators will continue to monitor the interactions, group formation, and genetic diversity of new wolves over winter and spring to document breeding (January/February) and denning (April/May) activity in Isle Royale’s wolf population. Closely monitoring social organization will provide insights into the genetic health of the population.  The NPS has partnered with Dr. Kristin Brzeski, wildlife geneticist at MTU, to sequence the Isle Royale wolf genome for long-term monitoring of genetic health of the population.

“We have a unique opportunity to look simultaneously at the past and future of Isle Royale wolves’ genetic health. With the death of M183, we can now more fully understand how genetic isolation and inbreeding impacted the historic wolf population and use that to better monitor the new founders. This is an exciting time and we will be using cutting-edge genetic tools to track reproduction, inbreeding, and genetic change through time, hopefully providing a piece of the puzzle for maintaining a thriving Isle Royale wolf population,” said Dr. Brzeski.

Multiple lines of investigations regarding this population will help the NPS evaluate the success of the project over the next few years. “We are using everything we can in our toolbox to track how this population interacts with each other, prey and the landscape.  We’ll continue to learn as much as we can moving forward to help with the decision to add wolves as needed to meet project objectives and document ecosystem effects.” stated Mark Romanski, the NPS project coordinator and Division Chief of Natural Resources at Isle Royale.

The current population includes 7 females and 8 males. All introduced wolves are from the Great Lakes Region, translocated from northeastern Minnesota (W001F), the Upper Peninsula of Michigan (W017M, W018F, W019M), mainland Ontario, Canada (W005F, W016M), and Michipicoten Island in northeastern Lake Superior, Ontario, Canada (W007M, W009M, W010M, W011F, W012M, W013M, W014F and W015F).

About the National Park Service. More than 20,000 National Park Service employees care for the 419 parks in the National Park System and work with communities across the nation to help preserve local history and create close-to-home recreational opportunities. Visit us at, on Facebook, Twitter, and YouTube


ISLE ROYALE, MI – More than a year into the National Park Service’s relocation effort to create strong wolf packs on Michigan’s remote Isle Royale, researchers have found the new predators are having no problem taking down members of the island’s teeming moose population.

Researchers who spent this summer tracking wolf kill sites found the remains of 60 prey animals. Most of these were moose, but evidence showed the wolves were also feasting on snowshoe hares and beavers.

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Photo courtesy of National Parks of Lake Superior Foundation

Photo courtesy of National Parks of Lake Superior Foundation

HOUGHTON, MICH- During a narrow weather window between storms last week, Ontario Ministry of Natural Resources and Forestry (OMNRF) successfully transferred four wolves to Isle Royale National Park.  Earlier this winter, severe weather on both sides of the border hampered the ability to capture and transfer wolves.  However, NPS staff worked diligently with ONMRF and over the course of four days successfully translocated Canadian wolves.  Two mainland wolves, one female and one male from the same pack and both with a black coat color variation, were captured on crown land near Wawa, Ontario, and transferred to Isle Royale.  Weather cleared long enough on Thursday to provide an opportunity to access Michipicoten Island Provincial Park, where two males were captured.

All the wolves were captured using OMNRF aircraft. The operation was coordinated by Kevin Middel, OMNRF, and Brent Patterson, OMNRF researcher and Trent University adjunct professor. Two National Park Service veterinarians, Michelle Verant and Jenny Powers along with Graham Crawshaw, an OMNRF veterinarian, supported the project to ensure animal welfare and assess the health of the wolves to be transferred.  Two veterinarians completed health assessments in Wawa and one veterinarian received the wolves on Isle Royale to ensure they were fit for release.  All four wolves were evaluated based on expectations for winter body conditions and deemed healthy enough for transfer and release.

The first Canadian wolf, a 65 pound female, arrived at Isle Royale on Tuesday afternoon.  The next day, OMNRF successfully captured a large 92 pound male from the same pack. He was held for evaluation and transported to Isle Royale and released on Thursday.  The clear skies on Thursday finally allowed OMNRF to reach Michipicoten Island Provincial Park.  While there, they captured two male wolves, one at the very end of the day as operations were winding down.  The first was delivered directly to Isle Royale and released in the late evening hours under clear starry skies on Thursday.  The team also captured the alpha male of the Michipicoten Island pack.  He was transported and released on Isle Royale Friday.

“I am impressed by the resilience this international team showed to overcome adversity and meet project objectives: polar vortex, federal government shutdown, complex aviation logistics, the list is endless,” stated Mark Romanski, Division Chief of Natural Resources for Isle Royale National Park and project manager for the reintroduction efforts.  He continued, “I am even more blown away by the resilience of these wolves who within hours after undergoing capture and handling and arriving on Isle Royale, immediately got on the trail of their pack mates.  These large males, all around 90 lbs., will almost certainly know what to do when they encounter a moose.”

NPS made the decision to restore predation, a key ecosystem dynamic, to Isle Royale National Park last June and sourcing the startup population from diverse geographic areas was essential to ensure genetic diversity. Canadian wolves have been a critical component to future success and graciously Ontario Premier Doug Ford approved the operation in October to support NPS objectives.  Understanding the  goal of balancing the male/female wolf ratio on Isle Royale combined with a need for robust wolf genetics from Canada, OMNRF personnel remained committed to providing wolves from Ontario to support the repopulation of Isle Royale.  Knowing weather could prevent access to Michipicoten Island, OMNRF worked with NPS to develop a strategy to acquire wolves from the mainland in Ontario if they were unable to access the island.

Superintendent of Isle Royale National Park, Phyllis Green stated: “ to see these wolves disappear into the forests of Isle Royale and to have an opportunity to start a new generation of wolves on the island fulfilled a major objective in the first year of reestablishing the population. The success reflected six months of planning and represented a major accomplishment by the agencies involved.” Changing ice conditions and winter storms foiled a previous attempt to acquire the Canadian wolves. This week afforded only four operating days between weather windows and the success of the operations can be attributed to the planning and expertise of the OMNRF. Green cited the amazing aircraft resources of the OMNRF, normally used for firefighting, which were critical in capturing the wolves and delivering them to Isle Royale National Park.

Additionally, the National Parks of Lake Superior Foundation (NPLSF) has played a crucial role in supporting and documenting the translocation efforts from Canada.  When this translocation phase of the project experienced cost overruns due to weather, the Chair, Sona Mehring, worked with the International Wolf Center to ensure the operation continued through the end of the week.  The Foundation plans to continue to support the remaining two years of the project and is developing documentary films regarding the project for audiences of all ages.


About the National Park Service. More than 20,000 National Park Service employees care for the 417 parks in the National Park System and work with communities across the nation to help preserve local history and create close-to-home recreational opportunities. Visit us at, on Facebook, Twitter, and YouTube


– Isle Royale sits like a gem in a cold ring of Lake Superior water, some 15 miles off the shore of Grand Portage, Minnesota. Its isolation has been key to the island’s preservation. It sits today as a national park, not much different from when Norwegian fisherman built the first fish camps on its shores in the mid-1800’s.

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