We arrived in Thunder Bay, Ontario late in the afternoon on January 14th. Lisa and I had driven the two days before from Montana, me flying in to meet her after she spent a week visiting her sisters and dropping off our puppy Phoebe who would spend our time on Isle Royale with her 6 cousins (Tarn, Elf, Frog, Bounder, Spring, and Kestrel – all pictured below). I had been visiting my folks and brother’s family in PA and enjoyed giving a talk on our Yellowstone wolf research to my parent’s retirement community just before I left.
Once in Thunder Bay, Lisa and I were responsible for making sure our food orders were ready to go and to coordinate with Mark Wiskemann from WiskAir who would fly us to Isle Royale National Park on Jan 16th in his Bell 412 helicopter. Dry goods had been stocked on the island in October but perishables, including meat, dairy, and vegetables had to be purchased just before we left. We picked up the prepared orders of over 30 pounds of meat and 13 ‘apple’ boxes of other food and met Rolf Peterson (Co-Project Leader from Michigan Technological University), Sarah Hoy (Research Assistant Professor, MTU), and Nate Hanks (National Park Service representative for the study) at the airport on the morning of our flight. John and Leah Vucetich (co-project leader and research scientist from MTU, respectively) were not able to join us this year due to personal reasons. We missed their company and companionship!
Flying conditions were favorable but we had to wait a couple of hours for the helicopter to return from a job it had just completed the two days prior relocating nine cow and one bull caribou from Michipicoten Island to the Slate Islands in northern Lake Superior. The most southern remnants of Ontario’s woodland or boreal caribou still occupy these small coastal islands and were relocated from one island to the other to remove caribou from Michipicoten to protect them from wolf predation and to repopulate the Slate Islands. When lake ice used to form frequently between the islands and the mainland, wolves and caribou could travel freely between land masses. However, due to effects from global warming trends these ice bridges freeze less frequently and trap vulnerable caribou on the islands with wolves with no way to escape. As soon as we unloaded from our return trip on February 12, Wisk Air would fly back to Michipicoten to relocate more caribou to Caribou Island a little further south in Lake Superior. To learn more about Ontario caribou, see Ontario Woodland Caribou Conservation
The 20 minute/30 mile flight from Thunder Bay to the 210 square mile island of Isle Royale is beautiful! We always thrill to see the land below us disappear as we begin our flight out over the icy-cold waters of Lake Superior and then get our first glimpse of the island on the distant horizon. Ice is always present on the lake, sometimes in solid sheets that appear dark black where snow has not covered them and other times in a broken mosaic of geometric patterns created by wind and water currents and that stretch as far as the eye can see. The formation of ice is significant for the ecology of Isle Royale because it is assumed that wolves had to have crossed the ice from Ontario in order to get to the island over 70 years ago. Any wolves that came over in subsequent years would have made the same crossing. Throughout much of the 20th century ice would freeze 8 out of 10 years but recently it is predicted that it will only freeze 2 out of 10 years, meaning that the opportunity for wolves to arrive from the mainland and infuse the dwindling population on the island with new genes is greatly reduced. Mark landed us safely in front of the Windigo bunkhouse on the west end of the island, our base camp for the next month.
When we left the island last February, much discussion surrounded the proposed National Park Service plan to augment the existing population of wolves with individuals from the mainland. Over the years, as many as 50 wolves had kept the moose population on Isle Royale in balance with the fragile island ecosystem but wolf numbers had dropped drastically since the 1980’s due to introduced disease and inbreeding depression and only two wolves were observed in 2017 (and two sets of tracks were found both by the plane and by Lisa and I on the island in January 2018). DNA gathered from wolf scats identified that the two wolves were closely related and could not produce viable offspring, the male was both father and half sibling to the female.
The moose population was estimated at ~1,600 and would grow at a predicted rate of 20% per year. Unchecked by wolf predation, this growing population could eventually deplete their winter forage. Overpopulation coupled with winter habitat depletion, severe winter weather, and the potential for winter tick infestation (which causes anemia and leaves moose exposed due to severe hair loss from grooming) could prove devastating. This scenario had played out in 1995-1996 when an estimated number of 2,400 moose (possibly the highest recorded moose densities in the world) were subjected to these conditions and over 1,200 died over the course of the winter. For details, see Annual Report 1995-96.
We were met on the island by current project pilot and Minnesota Fish and Game Warden Don Murray, who flew from Two Harbors, MN in his single-prop Aeronca Champ plane. Don is the grandson of the original project pilot (also Don Murray) who flew for the study for 19 years starting in 1959. He was succeeded by another Don (Glaser), a former employee and current air-taxi pilot in Alaska. Don Glaser still flies periodically for the project and was scheduled to be here for two weeks this winter. Unfortunately, he began having mechanical problems with his Piper Super-Cub (aka, The Flagship) and had to fly back to the mainland for repairs.
‘Young’ Don Murray, who first started flying for the project in 2008, is still flying his grandfather’s plane. Many years ago after Don ‘Senior’ stopped flying, he sold his plane and it was subsequently owned by at least two different pilots. One day, while driving through the Minnesota countryside, ‘Young’ Don saw the plane sitting abandoned and in disrepair in the middle of a field. He recognized the plane as his grandfather’s and approached the owner in the hopes of purchasing it. The plane at the time was not for sale but Don stayed in touch with the owner over the next few years, circumstances changed, and eventually he was able to buy it. Sixty years later, the red and white Champ with call sign ‘N1713E’ can still be seen flying low over Isle Royale surveying for moose and wolves.
Once ensconced on the island, Winter Study began! Rolf, a former Professor at MTU who has been working on the study since 1970, and Don Murray would fly the island (weather permitting) and count moose on 91-1 km2 survey plots in order to estimate population size. Because dense forest limits visibility of the moose on parts of the island, sightability correction factors (determined through years of surveying) have to be applied to counts to determine the total number of moose seen.
Rolf also coordinated the study from the bunkhouse, prepared most of the delicious morning and evening meals, and baked some wonderful fresh bread! Sarah flew periodically to help locate wolves, prepared the samples Lisa and I collected from the field for future chemical analyses, and added some tasty vegetarian meals to our menu. Nate was instrumental in keeping operations going in the bunkhouse by keeping it warm by constantly stoking the wood stove, maintaining generators to keep lights on, and restocking water supplies every day from our ice hole in Washington Harbor. Nate also prepared a wood-fired sauna twice a week, which we used to relax and soothe tired muscles and also to bathe. Everybody chipped in to make the bunkhouse a comfortable winter retreat!
Lisa and I continued our field work from last year spending most of our time skiing on the west end of the island based out of Windigo and 10 days on the east end at Daisy Farm . We collected fecal pellets and urine deposited in the snow from individual moose at both ends of the island for studies of individual diet composition and chemical analysis of urine to determine both the health of the moose and how much energy moose put into detoxifying their diet of balsam fir.
We also collected balsam fir twig samples from randomly selected plots vs used plots (where moose had recently browsed) to compare concentrations of plant secondary metabolites, defense chemicals that are concentrated in fir annual growth as a possible defense to moose herbivory. For more details on these topics, see this link to our blog from last year Isle Royale 2017 and this link to a paper that Lisa and I collected the data for Fir chemical defense and moose.
Researchers have known that moose on Isle Royale are more genetically susceptible to arthritis than other populations, probably because the small founder population that first swam to the island over 110 years ago carried the arthritis gene. Recently, they determined that IR moose also share some of the same genetic markers used for diagnosing arthritis in humans. In the coming years they would like to start a study following individual moose throughout their life to track these genetic markers and possibly the progression of arthritis in the hopes they can learn more about the disease to help humans. In that effort we are also focusing on collecting as many pellet samples from individual calves, which will then be identified from their DNA. These will become “known-aged” animals for this study. Over 23 total days in the field, Lisa and I skied and bushwhacked 168 miles across the island’s lakes and harbors and through dense forests, thickets and swamps.
Of course, we always enjoy the prospect of finding a shed moose antler!
While we are fascinated by all that we learn on Isle Royale in this, the 60th year of the study, we are also excited to experience this isolated wilderness that has seen minimal impact by humankind. Other than fires that were purposely set on the east end of the island for removing vegetation for copper mining exploration in the mid-1800s, large clear cutting around Siskiwit Lake on the south side of the island in 1936, and fires that burned much of the central part of the island that same year, much of the island has remained pristine virgin forest. Such old-growth forests do not exist in North America, especially in New England, where commercial forest practices have altered much of the landscape. The eastern end of the island is covered with lush conifer forests at the lower elevations – white spruce and balsam fir predominate, with black spruce the common species of wet boggy areas. Towering aspens are found scattered about the conifer forests particularly along the lake and harbor shores. The western end of the island, which has deeper nutrient rich soils left by the retreating glaciers, supports massive yellow birches and large expanses of sugar maples. On both ends of the island, white cedar predominates in almost impenetrable marshes and can be found mixed with hardwoods even in upper elevations.
The middle of the island, which burned in 1936 and grew back as a large white birch forest, provides little cover for moose in the winter, so consequently, wintering moose are found mostly on either end of the island or along the shorelines.
The mammalian fauna on the island is also unique. Only 15 miles from the mainland, there are only a few mammal species that live here: wolves, moose, red fox, red squirrel, snowshoe hare, pine marten, river otter, beaver, muskrat, deer mice, short-tailed weasel and mink. Other species have at one time inhabited the island but are not found here anymore, including little brown bats, coyote, lynx, and caribou. There are no bear, deer, porcupine, raccoon, bobcat, or gray squirrel. It’s amazing that these animals have never made it to the island!
We truly feel privileged to be part of this iconic wolf moose-study and to be able to experience this beautiful wilderness in the winter! We look forward to sharing our experiences from next year!