These northern squirrels have a spruce cone economy. Even before the middle of August they are frantically harvesting spruce cones (chiefly white spruce in the park). One afternoon a squirrel worked steadily in a group of spruces for almost 3 hours, cutting cones and giving them a flip with his mouth or paws. Hundreds were scattered about under the trees, and still they continued to rain and strike the ground with dull thuds. Occasionally the squirrel seemed to get his wires crossed and, instead of dropping a cone, would run all the way down the trunk with it.
Sometimes twigs bearing a cluster of cones are nipped off. In two or three sizeable caches all the cones were in clusters still attached to twigs. Perhaps this rather efficient method of handling cones is at times accentuated by certain individuals.
Red squirrel.
In September I have seen many caches scattered about on the forest floor as though piled hurriedly as a temporary expedient. One heap measured 5 feet long, 3 feet wide and about 7 inches deep. Possibly these heaps were later stored more carefully in secluded spots with the tips of the cones pointed downward. After the cones are stored, the squirrels continue to give them solicitous care. One spring when melting snow exposed a cache of cones, they were re-cached in various places, but each cone was first bitten into, and if spoiled was discarded. About the same time another cache of cones in a burrow was also removed and stored elsewhere.
Another food item that is stored in quantity is the mushroom. Many are placed on spruce branches where, if they do get wet, they will soon dry out and remain edible, and I once found great quantities stored in a cabin.
Aside from the cached foods, the red squirrels feed extensively, at least through the winter and spring, on the buds of spruce twigs. Often you may find many twigs on the ground with the tiny buds neatly removed. In Wyoming, I have found squirrels in summer living for days on the larvae in cottonwood galls, and I suspect such food may be eaten in Alaska too, where galls are found.
Northern flying squirrel.
Each squirrel commonly has two or more nests built of grasses, shredded bark, ptarmigan feathers, and hair of rabbits, moose or whatever is available. The squirrel piles this material on a branch until it is 2 or 3 feet high. One squirrel that I watched building a nest pushed himself into the middle of the heap. Soon the whole nest shook vigorously at intervals. Apparently he was forming a chamber.