The Food of Ground Squirrels

Abstract

So much of the territory of Western North America is the natural habitat of the ground squirrel and so greatly have they increased with the expansion of cultivated areas and so vast is their destruction to growing crops that a study of their food habits and an exact determlination of the damage produced by them is of interest and importance. These animals are prominently represented by one genus, Citellus, of which there are many species, enjoying a wide range over the western half of the continent. The species upon which this study is based is the Columbian ground squirrel (Citellus colunbiantus co lumbianus) found in Eastern Washington, Eastern Oregon and Northern Idaho. Its life, though modified by unusual climatic conditions, is probably representative of the genus. Observing these squirrels in the fields from day to day during the time of the harvest of their wild grasses and lupines, one is impressed with the aptness of the old generic terin Spermowphtilus, which expressed so fittingly one of the chief characteristics of these little seed liarvesters. It is a fascinating sight to see them, standing erect among the ripening vegetation, bear-like, gleaning their harvest with capable fingers and teeth. In season, purple lupines, the little rock clover (Eroditom) and waving seed-ladened bunch grass (Ayropyron) fill their fields with plenty. Here they toil through the hours of early morning and late afternoon sunshine, busily, in anticipation of the very urgent, present need of the allimportant nourishment against the near approaching time of estivation. Not that they are filling, for themselves, their hidden treasure houses, but that they may store up the necessary fat as a body food reserve which