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, https://belantlab.shinyapps.io/wolf-networks/ 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).

 

This story was first published as a National Park Service press release.

The National Park Service (NPS) in collaboration with the State University of New York – College of Environmental Science and Forestry (SUNY-ESF) concluded summer predation monitoring by the wolves introduced to the Isle Royale ecosystem in the fall of 2018 and winter of 2019. This marks the first time wolf predation has been monitored on Isle Royale during snow-free periods. The monitoring effort utilized the most recent advances in the study of wolf predation patterns.

Park staff and research partners from SUNY-ESF used GPS data from collars on the introduced wolves to identify “clusters” of locations that signified areas where wolves spent extended periods of time. Between May and October, field crews visited 381 of these sites, determined wolf behavior associated with site use, and located the remains of 60 prey, including primarily moose, beavers, and snowshoe hares.

Not unexpectedly, researchers found that the new wolves adapted well to the island environment, feeding on the moose and beaver populations of Isle Royale. A little more than half of prey remains (54.5%) were moose, demonstrating introduced wolves had few problems adjusting to this larger prey. Of the moose preyed upon, 63.4% were calves. Although not specifically designed to identify smaller prey, the predation monitoring also revealed the importance of beaver and snowshoe hare in the diets of wolves.

“Combining recent advances in technology with our knowledge of predator-prey relations will provide new insights, not only in the year-round foraging ecology of wolves on Isle Royale, but their overall role in this island ecosystem,” said Dr. Jerry Belant, Professor at SUNY-ESF and collaborative partner on wolf research.
Along with other research designed to identify ecosystem effects, the NPS and researchers from Michigan Technological University (MTU) and SUNY-ESF will continue to document wolf predation each winter and summer to monitor the restoration of wolf predation, its effects on Isle Royale’s moose population, and more importantly, the health of the island community as a whole.

GPS data led to the discovery of 24 moose carcasses by investigators and volunteers associated with MTU that will assist their long-term research, specifically the reconstruction of moose population estimates over time. Rolf Peterson, a research professor from MTU who helps direct citizen science teams of “Moosewatch” volunteers in the field, stated “our team members found it fascinating to explore clusters of wolf locations from last winter and spring, trying to locate bones from moose that had been killed or scavenged by wolves.”

In collaboration with several federal, provincial, state, tribal, and university partners, NPS is interested in investigating broad ecosystem change as the island adjusts to the return of predation, a key process in the ecosystem community dynamics of Isle Royale. This research will provide tangible evidence to help the NPS evaluate the success of its management actions as the project continues over the next few years.

“Restoring wolves is really about restoring integrity and resiliency to the ecosystem; making the ecosystem whole. Capturing the effects on the ecosystem as a result of our management actions is paramount to measuring the success of the program”, said Mark Romanski, Division Chief for Natural Resources at Isle Royale NP and project coordinator for the wolf translocation efforts.

The NPS and its collaborators will continue to monitor the new wolves as they settle into the island environment and to document ecosystem changes; wolf predation being just one of many metrics used to evaluate this ecosystem restoration effort.

This story was adapted from a press release from Isle Royale National Park.