what do they feed on?
Tree sap, insects, carrion
Northern flying squirrel
A major food source for the squirrels are fungi of various species, although they also eat lichens, mushrooms, all mast-crop nuts, tree sap, insects, carrion, bird eggs and nestlings, buds and flowers. 
where is oregon caves national monument and preserve located? A protected area in the northern Siskiyou Mountains of southwestern Oregon in the United States. which all animals can we see here? Black bear, cougar, northern flying squirrel, and Pacific giant salamander what sort of place does the third one select to live in? Coniferous and mixed coniferous forests across the top of North America, from Alaska to Nova Scotia, south to the mountains of North Carolina and Tennessee and west to Utah, Washington and Oregon.
wiki:13329573
Northern flying squirrel [SEP] Diet
A major food source for the squirrels are fungi of various species, although they also eat lichens, mushrooms, all mast-crop nuts, tree sap, insects, carrion, bird eggs and nestlings, buds and flowers. The squirrels are able to locate truffles by olfaction, though they also seem to use cues such as the presence of coarse woody debris, indicating a decaying log, and spatial memory of locations where truffles were found in the past. The northern flying squirrel is also known to cache food for when food supplies are lower. These caches can be in cavities in trees, as well as in the squirrels' nest.