From the field:
a wolf, a boggy lake, and some wet boots
By Izzy Evavold
'From the field' articles chronicle the adventures, difficulties, and hard-earned insights that come with doing fieldwork in the remote and wild Northwoods.
I could tell from satellite imagery when planning my route for fieldwork on June 4 that reaching one of the clusters of GPS-locations from Wolf Y2L, a 1-2 year old female wolf from the Blood Moon Pack, would be a swampy endeavor. Clusters of GPS-locations are areas where collared wolves have remained relatively stationary for more than 20 minutes, and therefore are potential locations where wolves have killed prey or found other food. Much of our day-to-day work involves hiking out to and searching every cluster from collared wolves to understand how wolves find food and survive in the Greater Voyageurs Ecosystem.
A GPS-collared wolf shortly before disappearing back into the woods. We are able to study the predation behavior of wolves by searching 'clusters' of GPS-locations that are transmitted to a website from the collar.
In order to reach this cluster of locations I would undoubtedly have to leave the security of dry ground and venture into a bog full of black spruce and sphagnum moss. Although bogs such as these are full of interesting plants like cranberries, cotton grass, and carnivorous pitcher plants, many bogs have hidden holes and depressions in the moss that can lead to soaked boots.
Most black spruce bogs start off as wet, mossy areas with enough solid ground to support trees. When bogs like these form around lakes, they slowly change as you get closer to the lake. Gradually, the ground becomes more wet and less solid. The black spruces become smaller and less dense, and eventually there are no trees at all. The bog transitions from solid ground to a floating mat of vegetation made of primarily moss, grass, and shrubs. Eventually, the bog mat gives way to open water—and the edge of the bog mat is where Y2L spent time and where I had to go!
An aerial view of the shoreline of a "boggy" lake. The orange and yellow part of the shoreline is floating bog mat—a very questionable place to walk if you want to stay dry in the field!
After planning my route and getting my gear together, I headed out into the field to check out what Y2L was doing in the bog. I made it to the first GPS-locations of this cluster without filling my boots with water but my feet were certainly damp. After searching around these GPS-locations for some time I found a small depression in the moss and shrubs that had wolf hair in it: a clear spot where Y2L had bedded down.
I then started moving toward some other GPS-locations further out into the bog and immediately smelled something foul. At first I thought the smell might be coming from the remains of a kill in the area but I was wrong. After a careful investigation the smell was actually coming from a fresh wolf scat not far from the bed.
A mature black spruce bog.
Most of the GPS-locations were centered around the bed and scat which meant Y2L likely spent most of her time bedded among the black spruces of the bog. But before I could draw any conclusions about what Y2L was doing at the cluster there were still several GPS-locations that needed to be searched. The first few GPS-locations were closer to the lake and right where the bog transitioned to a floating bog mat. I didn’t find evidence of a bed or a kill there. That left the last few GPS-locations which were all on the floating bog mat that extended far into the lake.
With some trepidation I started to walk out onto the floating bog mat. With every step or leap, the entire mat of moss, grass, and shrubs would tremble and move. As I worked my way toward the lake, the mat underfoot became less trustworthy and seemed ready to give way at any moment. Then, suddenly, I sunk into the moss and filled both boots in an instant.
A map showing the GPS-locations (white points) from Wolf Y2L, the route taken to get to these locations, and what was found when searching these GPS-locations.
After that, there was no need to try and keep my boots dry so I just went for it. But, I had to hop from one patch of shrubs to the next as quickly as I could so that I did not sink further into the bog. To my great relief and surprise, the edge of the floating bog mat was actually quite stable. I rested and took a much needed breather.
I followed the edge of the bog mat where it ran along the lake to reach the final GPS-locations in the cluster. When I reached the locations, I found four large white eggs that had been cracked open and completely cleaned on the inside. There were clear scrapes from teeth on the outside of each shell where Y2L broke them open.
About 10 feet out into the lake itself there was a large mound of dirt with a concave depression—a nest! Based on the size of the eggs and nest, it was clear Y2L had raided a trumpeter swan nest. Curiously, no egg fragments were in the nest so Y2L likely swam or waded out to retrieve each egg before eating them on the edge of the bog mat. After documenting these intriguing findings, I trudged back across the floating bog, through the black spruce, and back to solid ground.
One of the swan eggs consumed by Wolf Y2L.
I have searched many clusters of GPS-locations over the past two years on the Voyageurs Wolf Project but this one stood out to me. I anticipated that Y2L, like many wolves I have followed, had simply rested in the shade of black spruce trees in a bog. But, after searching all of the GPS-locations in the area, Y2L surprised me in her resourcefulness and had found a unique food source: swan eggs. Figuring this out was certainly a challenge and an adventure but it provided another rewarding glimpse into how wolves survive in the Northwoods.
About the author:
Izzy Evavold has been a field technician for the Voyageurs Wolf Project since April 2021. She has also been involved with the Isle Royale wolf-moose study through Michigan Technological University as a summer intern and winter study field technician. Izzy graduated from the University of Montana in the spring of 2020 with a major in wildlife biology and a minor in climate change studies. In her free time she is an avid canoer and enjoys catching snakes, toads, and frogs.