Eastern fox squirrels are native to southeastern and central regions of North America, from southern Canada to the Gulf Coast. Over the years, these adaptable mammals have spread westward, crossing the Great Plains along wooded river valleys, and reached Colorado via the South Platte and Arkansas River corridors; small populations were also introduced in the State's larger cities.
In their native range, fox squirrels feed primarily on mast (acorns, walnuts, hickory nuts, etc.) but also consume a variety of fruits, seeds, buds and bird eggs. The pioneers that spread west did not find an environment rich in mast and have adjusted their diet accordingly, concentrating on alternative food sources (as above); they have also developed a taste for the cambium layer of tree bark and seem to be especially fond of Russian olive and Siberian elm trees (also introduced species). Needless to say, some of their dietary habits have not been well received by Front Range homeowners.
Faced with a large crop of black walnuts, coating portions of our Missouri yard, I decided to bring a couple bucket loads to our Littleton farm, interested to know how they might be received by our local squirrel population. Before I had time to spread them through our wood border, a few of the fox squirrels had invaded the cache and mounds of black pulp appeared across our property; within 48 hours, all of the walnuts were consumed or buried. It was amazing to find that these Colorado fox squirrels, hundreds of generations removed from the eastern deciduous forest, would so quickly (and efficiently) dispatch this gift from their homeland. Instinctual memory runs deep!
