Observations of Northern Flying Squirrel Feeding Behavior: Use of Non-Truffle Food Items

Abstract

In the Pacific Northwest, the northern flying squirrel, Glaucomys sabrinus, consumes sporocarps of a wide variety of hypogeous mycorrhizal fungi (truffles). Numerous other foods are also consumed but are not well characterized by fecal pellet analysis either because they are more fully digested (seeds, nuts, fruits, vegetation) or because of the similarity among spore types (lichen photobionts, epigeous fungi). Thus, observations of squirrel foraging are important in characterizing non-truffle dietary components. As part of a trapping and telemetry study, we observed G. sabrinus foraging on 63 occasions; 34 were observations of non-truffle consumption. These foods included epigeous fungi, fruits and seeds, and conifer seedlings. We hypothesize G. sabrinus may consume more non-truffle foods than is indicated by fecal pellet analysis, and that such foods may be important nutritional supplements to a low-quality diet as well as substitutes for truffles in times or places of low truffle abundance. By availing themselves of other food sources, G. sabrinus may persist in otherwise marginal habitats, while also contributing to the dispersal of a wide diversity of fungi and increasing genetic diversity of fungal and microbial species.