Activity Patterns and Movements of Subarctic Voles

Activity and movements of female red-backed voles, Clethrionomys gapperi, were monitored by means of a radio telemetry system over a 14-month period in a 900 m2 natural enclosure. Animals exhibited a short-term (2-5 h) activity rhythm which remained relatively constant throughout the year and a circadian rhythm which shifted from diurnal in winter to nocturnal and crepuscular in summer. Among anestrous voles, movements and extra-nest activity were minimized during early winter when the subnivean space had not yet developed, and were maximized in late winter-early spring during snow-melt. In summer, activity and movements generally increased with the progression of reproductive phases from anestrous to lactating.