14 
THE CALIFOR^'IA GR()U^'D SQUIRREL. 
While no accidents to stock have resulted from this method of 
poisoninoj, care should be exercised in distributing it in places acces- 
sible to stock, particularly if feed is scarce. 
BISI LPHID OF ( ARBOX. 
Crude bisulphid, suitable for killing ground squirrels, prairie dogs, 
and other burrowing animals, costs about 8 cents per pound in 
oO-pound carboys or drums. It is a volatile lic[uid and rapidly loses 
strength on exposure to the air: hence, it should be kept in tightly 
corked bottles or cans. It should not be introduced haphazard, 
but should be used only in burrows where the animals have been 
seen to enter immediately before it is applied, so that none may be 
wasted. It should be employed in the following manner: 
A tablespoonful of crude bisulphid should be poured on a piece 
of horse manure, corncob, cotton waste or other absorptive material; 
this should be thrown as far as possible down the burrow and the 
opening closed immediately. Bisulphid can be used to best advan- 
tage after a rain, when the interspaces in the soil are filled with 
water, so that the fumes are less readily diffused into the surround- 
ing ground. 
In colonies w^here the holes are close together half an ounce of the 
bisulphid is enough for each burrow, but in the case of solitary 
burrows a full ounce should be used. 
In a field demonstration conducted by the Biological Survey, 
492 holes were treated with bisulphid. The quantity used was 3^ 
gallons, and two men were employed for one day in putting it out. 
Every squirrel in the colony was killed. 
TARRIXG CORN AGAIXST GROUXD SQUIRRELS. 
Seed corn may be protected by tarring with coal tar. At Pala, 
in southern California, during the season of 1909 a field of corn 
planted by Mr. Lonergan, superintendent of the Pala Reservation, 
was almost wholly destroyed by ground squirrels. A second planting 
(July 5-8) was treated with coal tar. The squirrels did not touch 
it, and the corn made a perfect stand. 
REMARKS. 
Some ranchmen still persist in using phosphorus or potassium 
cyanide preparations. These are no more effective than the starch- 
strychnine poison and their preparation and use are attended with 
grave dangers both to man and to farm animals. Potassium cyanide 
increases the danger to stock and birds without adding to the 
effectiveness of strychnine. Phosphorus is extremely fatal to swine, 
and in addition is liable, under certain conditions, to glow spon- 
taneously with a red heat and kindle fires. Fires started in this 
