654 THE MONTHLY BULLETIN. 



into conflict with man's interests. Extensive clearing of the sage- 

 brush and seeding of these clearings to grain and hay has doubtless 

 benefited the squirrels. Indeed, this is likely one of the factors that 

 accounts for their increase of late years as testified to by several of 

 the old-time residents whom we have interviewed. 



In Butte Valley, Siskiyou County, the Oregon Ground Squirrels 

 are popularly known as "bull dogs," in Modoc County as ''short-tails" 

 (evidently as distinguished from the longer tailed Douglas Ground 

 Squirrel), and elsewhere, locally, as "bobbies," "prairie dogs," 

 "gophers," and "woodchucks." The last three names, of course, are 

 misapplications of names properly belonging to quite different kinds of 

 rodents. 



In the latter part of May, 1918, the senior author accompanied Mr. 

 W. C. Jacobsen, State Superintendent of Eodent Control, in a tour 

 through northeastern California for the particular purpose of studying 

 the Oregon Ground Squirrel. In traveling eastward from Shasta 

 Valley, we first encountered this species toward the head of the Little 

 Shasta River, on the Mills ranch at about 4,200 feet altitude. Here 

 we found a field of vetch to be riddled with the burrows and secured one 

 of the animals to verify this, the westernmost record station for the 

 species. At Bull Meadows, a little east of Goose Nest Mountain, the 

 squirrels were exceedingly numerous on the uncultivated open ground 

 among scattering lodgepole pines. Subsequently we found them plen- 

 tiful around the margins of Grass Lake, nearly as far west, but due 

 south of Goose Nest. But it was on the floor of Butte Valley, from 

 the vicinity of Bray north to Dorris, wherever there were open grass 

 lands, that the Oregon Ground Squirrels simply swarmed. The fol- 

 lowing observations made May 16, 1918, on a ranch seven miles south 

 of Macdoel, will give an idea of the abundance of the animals where 

 conditions are most favorable to them. 



Taking a position at the right-angled intersection of two fences, 

 the observer counted the animals in the quarter-circle gaze thus 

 bounded and found that there were sixty-five squirrels in plain sight 

 within a distance of one hundred yards of him. This was about nine 

 o'clock in the forenoon of a bright day, when the squirrels were at 

 about the height of their daily activity aboveground. Young of the 

 year were included. 



Again, three adjacent plots of pasture were paced off, thirty-nine 

 paces square, and the open burrows counted. In one plot there were 

 151, in the second 182, in the third 194, an average of 176. This, fig- 

 ured out, makes 560 open burrows to the acre! If we allot one adult 

 squirrel to each five openings, which our observations showed to be 

 about the proper ratio, there would be 112 adults to the acre, not 

 counting young. Figuring, further, this would make somewhat over 

 70,000 squirrels per square mile ! This, however, would pertain only 

 in limited areas and to those pasture lands where little effort had yet 

 been, made to reduce the pests. The population of the sagebrush 

 plains and pine woods of Butte Valley would be much smaller. It is, 

 of course, the pasture lands and grainfields where the squirrels come 

 into chief conflict with man's interests, and this is where they are most 

 abundant. Some further estimates in this connection are likely to 

 prove worth while. 



