FOOD PREFERENCES OF CAPTIVE NORTHERN FLYING SQUIRRELS FROM THE LASSEN-NATIONAL-FOREST IN NORTHEASTERN CALIFORNIA

Hypogeous sporocarps of mycorrhizal fungi (truffles) are a common food of northern flying squirrels (Glaucomys sabrinus) and many other spec ies of small mammals. Forest management practices and natural disturba nces can affect both total amounts and species composition of truffles . We conducted cafeteria-style feeding trials to compare preferences o f northern flying squirrels captured in the Lassen National Forest in northeastern California among sporocarps of 5 species of fungi (3 truf fle species and 2 species of secotioid fungi), 2 species of lichens, a nd fir (Abies magnifica and A. concolor) seeds. Feeding trials were pe rformed on 7 male squirrels for 4 consecutive nights. Mean proportion of food eaten varied significantly among the 3 truffle species, betwee n the 2 species of secotioid fungi, and between the 2 lichen species. Mean proportion of food eaten was greatest for 2 of the truffle specie s, followed by the lichen Bryoria fremontii. These results indicate th at northern flying squirrels preferred truffles over certain types of other naturally occurring foods, and that preference varied significan tly among sporocarps of different fungal species. Natural disturbance and forest management that alter the species composition of fungal spo rocarps are likely to affect the availability of foods preferred by no rthern flying squirrels.