THE GROUND SQUIRRELS OP CALIFORNIA. 647 



tively few. To the westward they extend within a mile of the seacoast 

 in the vicinity of Eureka and at Cape Mendocino, but elsewhere mostly 

 not closer to the sea than eight or ten miles. Nowhere in the immediate 

 coast belt are they reported especially numerous or injurious. Pocket 

 gophers there loom up as the most destructive rodent. 



The voice and mannerisms of the Douglas Ground Squirrel are not 

 to us in any points that can be remembered materially different from 

 those of the California Ground Squirrel. A fair test of this could, of 

 course, only be made upon the two if studied side by side under per- 

 fectly normal conditions. In the nature of the case this is impossible, 

 for in no known locality do they occupy common ground. 



The tail is at all times the most conspicuous feature of this ground 

 squirrel. Sometimes when running to its burrow a squirrel will hold 

 its tail in a continuously vertical position, or this member may be 

 thrashed fore and aft. Ordinarily the tail is held nearly parallel to 

 the ground, with more or less of an arch in it. In this posture of tail 

 one is reminded strongly of the Gray Squirrel. 



Our own observations, and the testimony of people in general who 

 are familiar with several of our ground squirrels including the Douglas, 

 indicate that the latter is the most prone of all to climb trees. For 

 instance, near Tehama, June 8, 1912, several individuals were seen 

 well up in large white oaks (W. P. Taylor, MS). At Winslow, Glenn 

 County, June 19, 1912, one was seen in a buckeye, and several from 

 twelve to fifteen feet above the ground in willows and cottonwoods 

 (W. P. Taylor, MS). At Sisson, Siskiyou County, August 11, 1914, 

 one was seen thirty feet above the ground in an incense cedar (T. I. 

 Storer, MS). It is a common thing to see them perched upon the 

 tops of fence posts or stumps. Individuals may under certain circum- 

 stances so nearly resemble Gray Squirrels as to be actually mistaken 

 for them. This emphasis of the tree-climbing habit in the Douglas 

 Ground Squirrel is, suggestively enough, thus associated with greater 

 length of tail and grayer tone of color of tail, as compared with its 

 nearest relatives. It seems, also, that this species, more generally than 

 any other, raids orchard trees such as almond and apricot. 



The sure test, on the basis of behavior, of a ground squirrel as com- 

 pared with any true tree squirrel, such as the California Gray, is that 

 the former, no matter how high in a tree when discovered, will, upon 

 alarm, take to the ground as cjuickly as possible, and seek safety in a 

 burrow below ground, rather than make off through the branches from 

 tree to tree, or ascend into the uppermost foliage of a treetop. Not 

 infrequently, when surprised in a tree, a ground squirrel will for the 

 time being ''freeze" and attempt to escape being seen by remaining 

 motionless. But after being further disturbed and once starting, he 

 makes for the ground by the shortest route. 



The burrowing habits of the Douglas Squirrel are similar to those 

 of related species. Steep banks seem to be chosen for burrowing into, 

 whenever available. Many burrows open under rocks, bushes and 

 tree roots. On open, level ground, with no protective shelter at hand, 

 the mouths of the burrows are niarke.d by good-sized mounds, showing 

 the presence of an extensive system below ground. As far as we know, 

 no one has yet made a complete excavation of the burrow system of 

 this species. 



