Recent evidence for food storing in European ground squirrel (Spermophilus citellus)

Whereas European ground squirrels (Spermophilus citellus) do not utilize food caches during hibernation, it has occasionally been reported that they store food during the active season. Recent evidence for S. citellus maintaining food stores in summer arose during the long-term ecological supervision of a construction project in Vienna, Austria. From the onset of the project in 2012, ground squirrels were observed to forage on tubers of the tuberous vetchling (Lathyrus tuberosus). During the preparation of a building plot in July 2016, a cavity containing 380g of tubers of L. tuberosus was excavated by a digger when removing the upper 30 cm soil layer. When the construction area was expanded in July 2017, a ground squirrel repeatedly inspected a burrow on a future building plot, once carrying a tuber to the burrow. To examine if the burrow was vacant, it was stripped by layer, revealing a cache of 290g tubers in a blind-ending tunnel at a depth of about 90 cm. The structure consisted of one chamber without nesting material, and one tunnel containing the cache. We conclude that the burrow may have served as a hideout facilitating food intake while avoiding predation and other adverse external conditions.