Page:The Common Ground Squirrels of California.djvu/5



There are two methods of destroying ground squirrels: first, by means of poisoned grain, and, second, by the liberation of carbon bisulfid in their burrows. Which of the methods to be followed will depend upon the season, the poison grain method being more effective during the dry season, while the carbon bisulfid treatment will be more effective during the rainy season when there is sufficient soil moisture to prevent the general diffusion of the gas beyond the open burrows.

FIG. 2. Arranged from left to right are the ground squirrels of less economic importance in California, the Oregon ground squirrel (Citellus oregonus), golden-mantled ground squirrel (Callospermophilus chrysodeirus), Antelope ground squirrel (Ammospermophilus leucurus), and the desert, or round-tailed ground squirrel (Citellus tereticaudus).

Where ground squirrels are abundant over considerable areas, the simplest, most effective and least expensive way to destroy them is by the use of poisoned grain. Barley is the grain to be preferred, since it is more attractive to the squirrels and less likely to be eaten by birds.

The formula and method of preparation are as follows:
 * Clean barley.................................... 20 quarts.
 * Strychnia sulphate (ground or powdered)........ 1 ounce.
 * Saccharine..................................... 1 teaspoonful.
 * Gloss starch (ordinary laundry starch)................... ½teacupful.
 * Water.............................. 1½ pints.