Page:Natural History of the Ground Squirrels of California.djvu/73

Rh feet. The greatest depth reached beneath the surface of the ground was 45 inches. This was in rather dry pasture, and there was no sign of a water-table; the soil to this depth was only moderately damp.

The notes of the Oregon Ground Squirrel are of two sorts. The most impressive consists of a series of from 8 to 12 shrill, high-pitched calls, uttered in rapid succession—seep, seep, seep, seep, seep, seep, seep, seep, seep. The tendency is to weaken on the last few syllables, but the same pitch is nearly or quite maintained throughout. This call seems to be uttered only by adults, and seems to signify alarm at the first, or distant, approach of danger. One hears it taken up here and there all over a large meadow when it is first entered. Then there is a single shrill chirp of somewhat lower pitch, uttered now and then by either old or young. At times one will hear scarcely a note for many minutes, even when many of the squirrels are in sight, and then again the calls will be given back and forth from all sides.

One old female watched from a distance of 20 feet stood stock still for several minutes at the mouth of her burrow, in upright, "picket-pin" fashion. The fore feet she held against her stomach in front. When she gave the several syllabled call she opened her mouth very wide, depressing the tongue on to the floor of her mouth so that it could not be seen, and uttered the successive notes with much appearance of effort. The convulsive movements of the body were synchronous with the notes as uttered. The picket-pin attitude is really not so frequent as a crouching one, though when it is assumed it renders the squirrel visible a long way, especially where the grass is short. When feeding, the squirrel hunches over on its haunches, and uses both front feet and the fingers of these for holding and manipulating the food. When foraging the squirrels do much slinking along, with body horizontal and seemingly touching the ground. When a general alarm is sounded one sees them running in every direction, with a rather clumsy and not rapid, hopping gait. When so running the tail, short and never conspicuous, is held either out straight behind or raised at an angle of 30 degrees. Often when halting, or coming to a stand on the alert, the tail is twitched up from the horizontal several times in rapid succession, the whole body also twitching at the same time.

Rarely does an Oregon Ground Squirrel leave the ground, even to climb onto a rock or log. The body is relatively heavy and the general movements are far from nimble. In just one instance was a squirrel observed to have actually climbed; one individual was seen at Sugar Hill, Modoc County, up in a bush four feet above the ground (W. P. Taylor, MS). Marshes or very wet meadows are avoided; in other words, this species does not take to water. Still, we have the one instance of an individual, near Canby, Modoc County, seen (W. C. Jacobsen, MS) swimming across the Pit River. The current here was sluggish and the channel about eighteen feet wide. The act was to all appearances voluntary.

At the season of our special observations, the middle of May, the Oregon Ground Squirrels were seen to be feeding on practically every sort of pasture vegetation. Cuttings of meadow grass, blades and stems of grain, and leaves and stems of alfalfa were seen on their mounds or in the mouths of their burrows. As already stated, determination of