Intraspecific cache pilferage by larder-hoarding red squirrels (Tamiasciurus hudsonicus) in Kluane, Yukon

Pilfering is thought to play a role in the evolution of scatter-hoarding strategies; but is not well understood in larder-hoarding animals. I studied intraspecific pilfering in red squirrels in Kluane, YT, Canada. The purpose of this project was to estimate the natural rate of cache pilferage, and to examine variation in pilfering behaviour. Results from experimental removal of territory owners, suggested that younger squirrels with smaller food caches were more likely to pilfer when given the opportunity. Survival over-winter was dependent on the number of cones cached and pilfering squirrels were less likely to survive. Using a mark-recapture study of marked cones I found that few individuals (14%) did any pilfering and stolen cones represented only 0.3% of total cones cached. It is clear that pilfering occurs at a much lower rate in Kluane than reported for red squirrels in other regions, and is less than rates reported for scatter-hoarding species.