Anthropogenic sources dominate gray wolf mortality but leading cause varies with management regime

Despite changes in legislation and public attitudes towards large predators, human-caused mortality continues to impact survival and conservation of carnivore species. Understanding the drivers and timing of mortality is critical for informing evidence-based management and policy decisions aimed at improving carnivore conservation outcomes, particularly in areas with varying management regimes. Using GPS collar and mortality data representing 1,002 wolf-years from 608 wolves in Minnesota, Wisconsin, and Michigan USA during 2010–2023, we assessed cause-specific mortality and survival in relation to federal protection status, whether wolf harvest was allowed, sex-age class, and wolf residency. Human-caused mortalities represented 65% of recorded mortalities. Illegal kill represented 38% of mortalities and peaked in mid-November, concurrent with white-tailed deer firearm seasons in the region. Whether legal harvest was allowed did not influence mortality risk for causes other than legal kill. Mean annual regional wolf survival (0.74) was similar across years and sex-age categories and did not vary with protection status, but survival probability for resident wolves was greater than for non-residents. Legal kill was the greatest source of mortality for gray wolves in the western Great Lakes region in years when harvest was allowed, emphasizing the importance of continued population monitoring and adaptive management. Illegal kill was the greatest source of recorded mortality overall and was not reduced by federal protection, highlighting the need to enhance enforcement and address socio-political factors influencing public tolerance of wolves.