Page:The Common Ground Squirrels of California.djvu/6

— 4 — Dissolve the starch in a little cold water and add 1½ pints of boiling water, making a rather thick solution. While hot, stir in the strychnine and mix until free from lumps; then add the saccharine and beat thoroughly. Pour in the poisoned starch over the barley and stir rapidly until the poison is evenly distributed; then allow the grain to dry. When dry it will keep indefinitely without deterioration. By this method a coating of poison is formed on the outside of the grain, which acts much more quickly than if the grain is boiled or soaked in the poison. Squirrels are also readily killed by carrying such coated grain in their cheek pouches while storing food for future use.

PUTTING OUT THE POISON.

The poisoned grain should be scattered (not placed in heaps) on clean hard places about the colonies, the trails between the holes, along fences and roadsides and other places frequented by the squirrels. The time to apply it is during the dry season. If distributed just at the end of rainy season, late March or early April, it will destroy them during the breeding period, when one killed is equivalent to eight or nine later in the season. The poisoning may continue, however, throughout the summer and early fall. This poisoned grain as it is scattered about is not dangerous to stock, but is fatal to poultry.

COST.

The cost of preparing the material according to the formula given varies from about $4.00 to $4.75 per 100 pounds. One hundred pounds of the poiscned barley is sufficient to treat 200 or 300 acres. It may be distributed from horseback.

CARBON BISULFID.

A tablespoonful of crude carbon bisulfid is poured over a small ball of cotton waste, corn cob or other absorptive material and placed as far down the burrow as possible, and the hole is tamped in.

It is used to best advantage when the soil is wet. In wet soil the interspaces are filled with water and thus general diffusion of the gas through the soil is prevented.

Carbon bisulfid is a volatile liquid and rapidly loses its strength on exposure to air. It should therefore be kept in tight containers. It is also inflammable and explosive. It should be used only in burrows known to be inhabited by squirrels. The cost of crude carbon bisulfid is about 8 cents per pound in 50-pound carboys or drums.

The two methods described, poisoning and the carbon bisulfid treatment, may well supplement one another. Where the area is extensive the poison may first be used, because of its cheapness, and this followed in the proper season with the carbon bisulfid to clean up those that escape the poison.

Small areas may be freed from squirrels, but these are likely to be quickly reinvested again from the neighboring territory. It is often important, therefore, for the people of a district to unite in a coöperative campaign and free large areas from the squirrel pest.