Human avoidance, selection for darkness and prey activity explain wolf diel activity in a highly cultivated landscape in West-Central Europe

Wolves and other wildlife species that share habitats with humans with minor options for spatial avoidance must either tolerate frequent human encounters, which may be lethal, or allocate their activity to those periods of the day when the risk of encountering humans is smallest and the consequences least severe. This may force wolves in densely human-populated and cultivated landscapes to either become highly nocturnally active or habituate to human stimuli. Based on 6,220 camera trap images of adult wolves from eight territories in Denmark, we analyzed the extent to which diel activity patterns in a wolf population in a highly cultivated landscape with fragmented forests and extensive public access could be explained from diel variation in darkness, human activity, and prey (deer) activity. We found that diel activity correlated with all three factors simultaneously with human activity (negative) having the strongest total as well as partial effect, followed by darkness (positive) and deer activity (positive). Relative to a model that smoothed activity as a function of time of the day, the three factors accounted for 94% of the explainable diel variation in wolf activity. As most of the apparent selection for darkness could be explained by temporal human avoidance, we suggest that nocturnality (proportion of observations registered at night vs. day at equinox) is a useful proxy for investment in temporal human avoidance. In this study, wolf packs were 7.0 (95% CI: 5.0-9.7) times more active at night than at daytime, which makes Danish wolves amongst the most nocturnally active wolves reported so far. This result confirms the initial prediction that wolves with few options for spatial avoidance, invest heavily in temporal human avoidance.