Aimee Tallian, Jenny Hansen, Inger Maren Rivrud, Jenny Mattisson, Neri Horntvedt Thorsen, Joseph Bump, Örjan Johansson, Jonas Kindberg, Ole-Gunnar Støen

When large carnivores are attracted to exploit anthropogenic resources, they subject themselves to an increased human-induced disturbance and mortality. How they balance such risk-reward trade-offs remain largely unknown despite important fitness consequences. As adaptable generalist, brown bears (Ursus arctos) may show high behavioural plasticity and individual variation, with some individuals more prone to risk-taking than others.
We examine individual variation in risk-reward movement trade-offs of brown bears in alpine reindeer (Rangifer tarandus) calving areas in Idre Sámi reindeer herding community, Sweden. Bears in Sweden are primarily forest dwellers, but spring reindeer calving in open mountain terrain creates a seasonal pulse of food that attracts individuals to make short, opportunistic forays into risky, exposed areas to predate calves. Preliminary exploration reveals substantial variation in mountain forays and predation patterns, among individuals and across years within individuals. Using fine-scale GPS data from 33 collared bears in 2019-2024, we classified movement into behavioral states to detect mountain forays and to quantify individual variation in foray timing, frequency and duration. We then examined the drivers influencing the risk-reward movement trade-off of bears by linking movement decisions to environmental factors such as snow cover and reindeer calf availability, as well as bear demographic status. After accounting for these drivers, we expect the remaining variation to reflect individual differences, linked to experience and risk-proneness.
Our findings will advance our understanding of how large carnivores balance risks with rewards when exploiting anthropogenic attractive sinks, emphasizing the role of individual behavioral plasticity in shaping movement decisions. This knowledge has direct applied relevance for the ongoing debate between Sámi communities and authorities on developing locally adapted management strategies.