Unimodal activity pattern in forest-dwelling chamois: typical behaviour or interspecific avoidance?

Abstract

Daily activity rhythms in mammals are influenced by a range of biotic and abiotic factors. During warm periods, mountain ungulates living in open areas typically show a bimodal pattern of activity rhythms, with peaks at dawn and dusk. To date, however, little is known about the activity patterns of mountain ungulates living in forested habitats and in areas where large predators are present. Using camera traps over a 6-month period between May and October of 2012, we investigated the activity pattern of a chamois population dwelling in the forests of the northern Mount Velebit region (Croatia) and its overlap with the activity patterns of potential predators (brown bear, grey wolf) and competitors (wild boar). Chamois showed a peak of activity between 5:00 a.m. and 7:00 a.m., when 65 % of individuals were photographed. Contrary to previous literature on chamois, we found evidence for a unimodal pattern of activity with a peak in the early morning hours: At a seasonal level, this pattern remained fairly consistent, though the activity at dusk increased in the warmest months. The main peak of activity occurred during periods of decreased activity of potential predators and competitors, and chamois exhibited the least tolerance for overlap with grey wolf. Further studies are needed to clarify whether this pattern is typical of forest-dwelling populations or if it reflects a temporal niche shift, possibly as a strategy to avoid predators.