THE GROUND SQUIRRELS OF CALIFORNIA. 



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dependent upon the sequence in which they become available. Thus, 

 alfilaria is eaten during winter and early spring ; then the foxtail crop 

 claims attention ; and the bur clover, after its seeds ripen, is harvested 

 all through midsummer and autumn. Of course the above statements 

 are only of local application. 



Examination of the food stores of ground squirrels would go far 

 toward providing adequate knowledge of their food habits. Such inves- 

 tigations should be made preferably in the fall. Specific information 

 now available is as follows: 



In digging out a colonial burrow near Bakersfield, Kern County, on 

 May 3, 1918, a storehouse was uncovered. This consisted of a cavity 

 or pocket off the main run (see a, fig. 8), which measured five and a 

 half by eight inches in two diameters and was eighteen inches beneath 

 the surface of the ground. The stored food consisted of a double hand- 

 ful of nearly dry heads of foxtail grass carefully packed in dry sand. 

 A few alfilaria seeds were also included with the foxtail, but alfilaria 

 was scarce at this locality. 



Upward of fifty of the button-like seeds or "cheeses" of the mallow 

 (Malva) were observed at the entrance of another burrow at the same 

 place, but the observer was unable to determine whether or not these 

 seeds were being stored. The mallow seeds were found for the most 

 part on the lookout station at the entrance to the burrow. 



"At Modesto in May, 1909, Piper found stores of alfilaria seeds 

 packed in cavities and well mixed with dry sand. In December of the 

 same year he examined a number of stores of grain unearthed by a 

 farmer while scraping and leveling his land. Each of these caches 

 consisted of from a pint to a quart of oats stored in cavities and packed 

 in dry sand. They varied from 8 to 18 inches in depth beneath the 

 surface ; some were in short blind holes ; others at the ends of branches 

 of the main burrow" (Merriam, 1910, p. 5). 



An idea of the quantity of food eaten by the California Ground 

 Squirrel can be derived from the following data : 



A female taken near Coulterville, Mariposa County, on June 3, 1915, 

 weighed 553.5 grams, or about a pound and a quarter. The stomach 

 and its contents alone weighed 77.5 grams, or about 2| ounces (C. L. 

 Camp, MS). Figuring out the ascertained weight of the stomach in 

 other individuals, 5 grams, the ratio of stomach contents to total weight 

 in this squirrel proves to have been about 1 to 7. The material repre- 

 sented is presumed to have been fresh green stuff. 



Some experiments have been carried on at the Museum with captive 

 squirrels with the purpose of determining the amount of green forage 

 consumed daily. Fifty grams, or nearly two ounces, of green alfilaria 

 was found to be the average daily ration for an average-sized squirrel. 

 In cases where all food had been withheld from the squirrels the previ- 

 ous day, the greatest amount of succulent alfilaria, the favorite food of 

 the squirrel, consumed in one day was 80 grams, or somewhat less than 

 three ounces. 



Five immature ground squirrels taken July 26, 1918, near Walnut 

 Creek, Contra Costa County, gave an average total weight of 504.3 

 (427.2-517.2) each in grams. The average weight of the stomach con- 

 tents in these five squirrels was 13.2 (10.3-19.0), so that the average 

 ratio of the weight of the stomach contents to the total weight was 



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