710 



THE COLUMBIAN GROUND SQUIRREL. 

 (Citellus columbianus columbianus.) 



THE MONTHLY BULLETIN. 



By W. T. SHAW. 



PLATE VI. 



INTRODUCTORY. 



In the southeastern part of the state of Washington, in a bunch- grass 

 plateau, called the Palouse Country, is found one of the larger species 

 of ground squirrel, commonly known as the Columbian ground squirrel. 

 From this region, according to Mr. E. W. Nelson, its geographic range 

 extends as follows: "In a general way the species inhabits the Blue 

 Mountain Plateau of northeastern Oregon and southeastern Washington 

 and western Idaho from the Seven Devils Mountains north to Lake 

 Pend Oreille and east of Ketcham in the Sawtooth and in Montana 

 to the Bitter Root Valley and Helena, thence northward into Alberta 

 and British Columbia to an unknown distance. The relationship with 

 other species on the north has not been thoroughly worked out. " It is 

 of this species we wish to write, giving a brief but fairly comprehensive 

 outline of its life history. 



That the life cycle of this animal is most remarkable is probably due 

 to the fact of its having lived so long under peculiar climatic conditions. 

 Although now the territory in southeastern Washington has been turned 

 into a great grainfield, it has not always been so ; and not long ago, 

 where wheat now waves, stretched vast rolling plains of early-maturing 

 bunch grass. Then, by the first of July the moisture conditions were 

 such that wild vegetation began to ripen and the squirrel, finding 

 himself deprived of moisture obtained from the juices of plants about 

 him, and in many cases living far from water, faced starvation or an 

 alternative. The alternative was aestivation or summer sleep and within 

 a month, in the midst of an ample cereal harvest, this species, so 

 abundant in numbers, disappears entirely from the fields and is seen 

 no more until the snows of late February are beginning to melt. This 

 resort to aestivation, to circumvent death from thirst, passes uninter- 

 ruptedly into a more profound condition of hibernation and in his 

 restricted hibernating den he passes nearly seven months each year in 

 a state of inactivity. 



These countless thousands of squirrels inhabiting this rich agricul- 

 tural region became a very serious menace to the profitable raising of 

 wheat, and it was decided by the Washington Agricultural Experiment 

 Station to study the problem of the life history of this animal, hoping 

 to obtain information upon which might be based better methods of 

 control than those hitherto practiced. In June, 1910, such an investi- 

 gation was started and has been continued with earnestness through the 

 subsequent years. At the outset many facts of interest were noted but 

 it soon was learned that the complete life cycle could not be obtained 

 from squirrels in the wild state. Accordingly, extensive yards were 

 constructed in which the animals to be studied were restricted. For 

 convenience of reference, a general term, citellary [ci-tel'-lary] was 



PROBLEM. 



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