THE PLACEMENT, RECOVERY, AND LOSS OF SCATTER HOARDS BY EASTERN CHIPMUNKS, TAMIAS-STRIATUS

Although eastern chipmunks typically larder hoard food in their burrows, some scatter hoarding occurs, especially by newly emerged juveniles and by females with young. To examine patterns of scatter hoard placement and their adaptive significance, we used standard food provisioning tests followed by continuous monitoring to determine the longevity and fate of scatter hoards. Longevity of scatter hoards was low (median 74 min) and pilferage was high (46%). Chipmunks placed scatter hoards away from the patch, closer to their burrow and within the defended area of primary use. Scatter hoard placement was affected by the number of competitors at the patch. However, juveniles and females with young differed slightly in their responses. Competitors that approached scatter hoards were sometimes chased away by the scatter hoard's owner, and the scatter hoard was moved to another location by the owner. Females with young recovered their largest scatter hoards first, but there was little additional pattern in scatter hoard recovery. An experiment using simulated scatter hoards showed that scatter hoards farther from a patch of food lasted longer and that disturbing and marking scatter hoards reduced their longevity. These observations indicate: (1) that scatter hoard placement is more related to avoiding pilferage of completed caches than to rapidly sequestering food items from an ephemeral patch and (2) that optimal cache distribution may be affected by the cache-defense ability of individuals, by the relationship between competitor density and cache security near the patch, and by the territorial behavior of neighboring conspecifics.