Abstract 88 – Using a behavioural classification of accelerometry data to evaluate effects of hunting risk on Scandinavian brown bear behaviour

Jeanne Clermont, Andreas Zedrosser, Ludovick Brown, Frank Rosell, Gunn Elisabeth
Sydtveit Rekvik, Jonas Kindberg, Fanie Pelletier

Predation may indirectly influence prey’s fitness and population dynamics through behavioural
adjustments in response to perceived predation risk. These non-consumptive effects of
predation can also arise from hunting by humans, but they remain less understood compared
to those arising from natural predators. Advances in biologging allow detailed assessments of
the activity budgets of elusive wildlife, increasing the potential to uncover the non-consumptive
effects of human activities on animals. We used tri-axial accelerometry to record the daily
activity of 24 Scandinavian brown bears from a heavily hunted population in Sweden (29 bear-
years, 2015-2022). We used a supervised machine learning algorithm trained with observations
of captive brown bears to classify the accelerometry data into four behaviours, i.e., running,
walking, feeding, and resting, with an overall precision of 95%. We then evaluated changes in
bear activity budgets before and during the hunting season. We found that bears exhibit a
bimodal daily activity pattern, being most active at dusk and dawn, and resting around midday
and midnight. However, during the hunting season, females showed a higher probability of
being active during the day than before the hunting season, while males showed the opposite
pattern by becoming more nocturnal. Since legal hunting occurs mostly during daylight hours,
these results suggest that bears modify their activity level as an anti-predator response to
hunting risk, but that tactics differ between sexes. Additionally, daily number of running bouts
did not vary between seasons in both sexes, but females’ proportion of running bouts occurring
during legal hunting hours was higher during the hunting season than prior to it, suggesting
they may use running as a tactic to avoid hunters. More detailed assessments of wild animal
behaviours have the potential to increase our understanding of the impacts of human activity
on wildlife and help guide conservation decisions.