Date of Award
Master of Science
Beavers can be a significant prey item for wolves in boreal systems but how wolves hunt beavers is largely unknown. I inferred how wolves hunt beavers by identifying 22 kill sites using clusters of locations from GPS-collared wolves in Voyageurs National Park, Minnesota. Where wolves killed beavers varied seasonally with the majority (58%) of kills in the spring occurring below dams and on shorelines while the majority (80%) of kills in the fall were near feeding trails and canals. I deduced that the typical hunting strategy has 3 components: 1) waiting near areas of high beaver use until a beaver comes near or on shore, 2) using concealment, and 3) immediately attacking the beaver, or ambushing the beaver by cutting off access to water.
Wolf diet is commonly estimated via scat analysis, and several studies have concluded that scat collection method can bias diet estimates. I tested whether different scat collection methods yield different diet estimates after accounting for other biases. I collected scats (2,406 scats) monthly from 4 packs via 3 scat collection methods in the Voyageurs National Park, Minnesota area, during April 2015–October 2015. Scat collection method did not yield different diet estimates but I did document temporal, inter-pack, and age class variability in diet estimates. To better estimate wolf population diets, researchers should collect ≥10–20 adult scats/pack/month from homesites and/or opportunistically from packs that are representative of the population of interest.
Gable, Thomas, "Wolf Predation: Where and How Wolves Kill Beavers, and Confronting the Biases in Scat-Based Diet Studies" (2016). All NMU Master's Theses. 122.