Page:Natural History of the Ground Squirrels of California.djvu/80

662 Probably because of the open nature of their forage ground, these squirrels seem exceptionally timid. The shrill cries of alarm greeting the invader of a meadow upon his approach are quickly followed by total disappearance of the animals, at least for the time being. Each individual seems not to wander usually more than a few yards from the mouth of its burrow, so that but a short run intervenes at any moment between it and safety. The tail is held down when running, not elevated nor waved. The gait is rather slow and clumsy, impressing one observer as resembling that of a short-legged dog. "Where the grass is short there is little up-and-down movement of the body shown in running; but in high grass, instead of parting the stalks and pressing them aside as it progresses, the animal advances by a series of jumps each of which carries it up clear of the grass so that it can glimpse about for a possible enemy" (T. I. Storer, MS).

When within but a few feet of the mouth of its burrow and first taking alarm, a squirrel will rise quickly on its haunches and assume the rigid, upright, "picket-pin" posture (see fig. 20c). This usually brings the animal's head well above the grass tops, so that it can get a good view all about. Also it can then be seen a long way, looking in the distance like a tent-stake or picket-pin out on the meadow. During this pose the fore limbs are pressed closely against the body. Sometimes the animal rises still higher, supporting its whole body on its hind feet and using its stubby tail as a prop (C. L. Camp, MS). The fact that the nose is continually twitched up and down, as if the animal were drawing in air, suggests that the sense of smell may be keen and that it may be used to determine the nature of a supposed enemy. If the observer continues his approach the squirrel suddenly deserts its "picket-pin" pose and dashes for its burrow, where it may hesitate a moment on all fours for one final look before diving out of sight.

The voice of this squirrel closely resembles that of the Oregon Ground Squirrel. The usual call of warning consists of a series of from five to eight short shrill whistles uttered in quick succession and weakening toward the last. Females warn their young when foraging abroad with a lower-pitched, double note, or bark, e-chert'. A single note, sirt, is also frequently heard.

The burrows of the Belding Ground Squirrel are generally located in the meadows which form their forage grounds. Sometimes, near timber line, one finds them in the scant gravelly soil between granite boulders, but always in or near patches of the kind of bunch grass occurring at such altitudes. The mounds are rarely conspicuous, and the holes open up to the surface steeply. Often there is no surplus earth at all around the mouths of the burrows, but this condition might be accounted for by the effects of washing from heavy rain or melting snow. Several measurements of burrows gave an average diameter of two inches. The extent of the underground burrow system has only been tested out in one instance (see fig. 21). In this case the burrow was located in a wet meadow, snowbanks melting all about at the time (June 28), and it proved to be shallow, reaching an extreme depth of only about thirteen inches. But blind branches directed downward indicated the probability of greater depth later in the season when the water table had lowered and the soil dried out. The total length of this burrow system, including all its branches, was close to 54 feet.