Skip to main content
SLU publication database (SLUpub)

Research article2019Peer reviewed

Fluctuating mast production does not drive Scandinavian brown bear behavior

Hertel, Anne G.; Zedrosser, Andreas; Kindberg, Jonas; Langvall, Ola; Swenson, Jon E.


Bears often rely on soft or hard mast during fall hyperphagia when they increase body mass in preparation for winter hibernation. Studies of North American and Japanese bear populations suggest they respond to years of mast crop failure by increasing movement rates and roaming farther, with an increase in human-wildlife conflicts. In southcentral Sweden, brown bears (Ursus arctos) primarily feed on bilberry (Vaccinium myrtillus) and lingonberry (V. vitis-idaea) during hyperphagia. We hypothesized that berry production affects movement, activity, and space use behaviors of bears in Sweden, which have the potential to increase human-bear encounters. We tested whether seasonal activity patterns, human settlement visits, and clearcut selection ratios were affected by bilberry and lingonberry productivity between 2007 and 2017 with linear and generalized linear mixed effect models. Contrary to our expectations, we did not find that bears moved more or maintained larger home ranges in years of low berry production. Bears were slightly more active in years of higher bilberry production, but variation in behavior was primarily explained by demographic group and individual differences. Bears rarely visited human settlements and the number of visits did not increase in relation to shortage of natural foods. Likewise, population-level selection for clearcuts was unrelated to berry production but reflected a differential food search behavior in the 2 peak berry seasons, with higher clearcut selection ratios during the lingonberry season. Only 12 bears regularly used agricultural fields, which were too few to relate field visits to berry production, but all bears visited fields more often during the later lingonberry season. We suggest that weaker fluctuations in berry production, a continuous spatial distribution of berries, and an apparent absence of forage-limiting exploitative intra- or interspecific competition contribute to brown bears in Scandinavia being less food limited than bears in North America or Japan, which might help to explain the low number of human-bear conflicts in Sweden. Factors potentially influencing encounters and actual or perceived conflict between bears and humans differ among populations because of a different distribution of natural and non-natural food resources or differences in the magnitude of variation in food abundance among years. These data are important to consider when communicating causes of human-wildlife conflicts to the public. (c) 2018 The Wildlife Society.


food abundance; foraging; human-wildlife conflict; Ursus arctos; Vaccinium myrtillus

Published in

Journal of Wildlife Management
2019, Volume: 83, number: 3, pages: 657-668