Diets of Northern Flying Squirrels, Glaucomys sabrinus, in southeast Alaska

We examined the diet of the Northern Flying Squirrel (Glaucomys sabrinus) during summer and autumn seasons in temperate rain-forest habitat of Southeast Alaska, a region in which the ecology of this species is poorly understood. Truffles, a food item that is commonly consumed by squirrels during snow-free periods outside of Alaska, were present less frequently in squirrel feces than two other food items, epigeous fungi and vegetation, although no food item dominated fecal composition. Truffles were less frequent in fecal samples from mixed-conifer muskeg habitats than from old-growth forest habitats. Overall, we found that squirrels consumed a total of five truffle genera; Elaphomyces and Hymenogaster being the most common. Compared to populations in the western contiguous United States, squirrel populations in Southeast Alaska consumed truffles less frequently and consumed a smaller total number of truffle genera. In addition, samples from individual squirrels in Alaska tended to contain fewer genera than samples from the contiguous United States. Finally, squirrels Alaska consumed other food items such as vascular vegetation, lichens, and mushrooms more frequently than squirrels in other geographic areas. These patterns suggest that the association between flying squirrels and truffles may be relatively weaker in Southeast Alaska than has been documented elsewhere. Consequently, additional information on life history and ecology of flying squirrels is warranted before forest management guidelines can be developed.