Scatterhoarders move pilfered seeds into their burrows

Abstract

Although cache pilferage by food-hoarding animals has been well investigated, whether cache pilfering contributes to seed redistribution remains to be explored. In this study, we presented seeds exposed on the ground (including clumped and scattered seeds) and buried in artificial caches to Siberian chipmunks Tamias sibiricus and Korean wood mice Apodemus peninsulae exhibiting different food-hoarding behaviors, to investigate how seed distribution patterns affected seed fates and where pilfered seeds have gone in rodent-proof enclosures. Our results showed that both T. sibiricus and A. peninsulae handled more seeds exposed on the ground than buried in the caches. Scattered seeds were less likely to be eaten by rodents compared to clumped seeds and those buried in artificial caches. Exposed seeds in the enclosures were more likely to be scatterhoarded by T. sibiricus, while pilfered seeds from artificial caches were more likely to be larderhoarded than those easily accessible on the ground. Although buried seeds in artificial caches were less likely to be pilfered by rodents, both scatterhoarder (T. sibiricus) and larderhoarder (A. peninsulae) concealed pilfered seeds in their burrows. We also found that primary scatterhoarder T. sibiricus appeared to be effective pilferer, whereas A. peninsulae that primarily larderhoard seeds seemed to be poor pilferer, providing further evidence that the ability of food-hoarding animals to pilfer is correlated with how extensively they scatterhoard seeds. Our study highlights the importance of seed distribution patterns in affecting the hoarding behavior of scatterhoarding rodents, but not for larderhoarding rodents. Although cache pilferage by food-hoarding animals has been well investigated, whether cache pilfering contributes to seed redistribution remains to be well explored. Our study first showed that both scatterhoarders and larderhoarders concealed pilfered seeds in their burrows, challenging the previous assumption that cache pilferage will result in redistribution of dispersed seeds.