How humans are changing the natural landscape is also changing where wolves (Canis lupus) hunt for deer. A recently published study in the journal Ecological Applications looked at how different human activities, such as logging and building, influence where and how wolves hunt young white-tailed deer (Odocoileus virginianus) in North American boreal forests in Minnesota.
It’s estimated there are about 498 wolf packs in Minnesota (related: These Wolves in Minnesota are Very Very Territorial). The study was based in the 1,960 square kilometer Greater Voyageurs Ecosystem (GVE) which includes Voyageurs National Park, Kabetogama State Forest, the Superior National Forest, land owned by St. Louis County, timber company properties, and private land. Within the GVW, researchers analyzed sites where fawn had been killed by wolves to look at the spatial patterns of these hunts.
The study found that human buildings, roads, and timber harvesting have a significant impact on where wolves hunt fawn. Contrary to the idea that deers find refuge in human-altered areas (known as the “human shield hypothesis), the study found that wolves tend to kill fawn closer to residential buildings than expected. Fawn are also more likely to be killed in recently-logged areas.
There are several hypothesis to explain how impact of human structures and timber harvesting have changed where wolves hunt for fawn.
First, man-made changes make it easier for wolves to move efficiently and find deer. Linear disturbances such as roads, power lines, and hunting trails make it easier for wolves to quickly move from hunting ground to hunting ground. Wolves rely more on their sense of smell rather than vision to locate hidden young deer, and linear infrastructure can make it easier to pick up on olfactory clues that help the wolves find prey. The study’s finding in this area aligns with previous studies showing that predators like wolves and American black bears tend to prefer roads and other straight pathways in North American forests as it makes their foraging more efficient.
Clearcutting also increases the likelihood that deer will be present. Harvesting timber creates large stands of early successional forest. These emerging forests, particularly in clear cut areas less than five years old, contain prime foraging for ungulates such as moose (Alces alces) and deer (Odocoileus spp.) in the form of saplings and understory vegetation such as aspen. The vegetation in a young forest also provides more hiding spots for fawn which further attract deer.
The study also found that wolf predation of fawn was high near cabins and other human infrastructure. The authors of the study hypothesized that a higher availability of prey in in the form of deer in these areas created an allure strong enough to override the wolves’ natural avoidance of humans. The researchers also noted that most of the housing in the study area was seasonal and that perhaps there wasn’t enough constant presence of humans in the area for it to make a difference in the hunting behavior of the wolves.
More research is needed to understand the longer-term impact that a changing predator-prey dynamic has on white-tailed deer.
These findings from this study can provide new understanding into how predators and prey interact and how human activities are changing these dynamics. This information is important for managing and preserving the balance between wolves and deer, especially as their habitats continue to overlap due to human influences.
Johnson‐Bice, S. M., Gable, T. D., Homkes, A. T., Windels, S. K., Bump, J. K., & Bruggink, J. G. (2023). Logging, linear features, and human infrastructure shape the spatial dynamics of wolf predation on an ungulate neonate. Ecological Applications, 33(7), e2911. https://doi.org/10.1002/eap.2911