78 BULLETIN 479, U. S. DEPARTMENT OF AGRICULTURE. 



from the stove. Mix together 1 ounce of powdered strychnine (alkaloid) 1 and 

 1 ounce of powdered bicarbonate of soda and slir with the starch to a smooth, 

 creamy mass. Stir in 1 tablespoooful of glycerine and finally one-eighth ounce 

 of saccharine. Apply to 20 quarts of good, clean oats or wheat and mix thor- 

 oughly to coat cadi kernel. 



This poison is effective in destroying chipmunks, kangaroo rats, pocket mice, 

 the smaller species of ground squirrels, and at times kills white-footed mice. 



Oats are generally the most successful bait. On account of the skill of chip- 

 munks in " hulling." wheat is more effective for these animals. Barley, in 

 the proportion of 16 quarts to each ounce of strychnine, has given best results 

 in destroying the larger " digger " ground squirrels ami is most effective during 

 the dry summer season. 



There is another process of applying the poison which is an improvement 

 over that just described, in that it delays the taste of strychnine, the intense 

 bitterness of which is the greatest factor detracting from success in poisoning 

 certain rodents. This poison has been used With great effect against rodents 

 which have hitherto exhibited marked aversion to strychnine baits. The fact 

 that the poison coating readily separates from the bait is also of importance 

 to the success of this preparation, especially for such rodents as habitually 

 " hull " grain. In the process of hulling sufficient strychnine to kill flakes off 

 in the animals' mouths. Grain poisoned in this way must be handled care- 

 fully to avoid loosening or grinding off the poison coating. It should be 

 freshly prepared in small quantities, for use each day, as follows: 



Mix together one-fourth ounce of powdered strychnine alkaloid, one-fourth 

 ounce of powdered bicarbonate of soda, a scant one-half treasoonful of saccha- 

 rine, two heaping tablespoonfuls of dry powdered starch ; stir with enough cold 

 water to make a thin paste of the consistency of cream. Apply gradually to the 

 material to be used as bait, mixing vigorously to distribute the poison as evenly 

 as may be and to prevent the formation of lumps. 



Oats, wheat, cracked corn, and dry coarse meals of all kinds may be so 

 poisoned. For ground squirrels, chipmunks, and medium-sized rodents gen- 

 erally, one-fourth ounce of strychnine is sufficient for 4 quarts of bait ; but 

 for white-footed mice the amount of bait may be doubled. Among baits espe- 

 cially attractive to the latter animals may be mentioned pine seeds (both 

 whole and crushed seeds worth trial), roasted peanuts crushed to a coarse 

 meal, crushed wheat, and mixtures of crushed or chopped grains. 



Poisoned baits of sweet potato almost invariably kill pocket gophers if 

 placed in the underground runs without too much disturbance of the latter. 

 Baits of carrot or parsnip may be substituted, or corn, poisoned as in the first 

 formula described, but none of these are so completely successful as sweet 

 potatoes. 



The baits of vegetables should be cut about 1 inch long and one-half inch 

 square and washed and drained. From a pepperbox slowly sift one-eighth ounce 

 of powdered strychnine (alkaloid) and one-tenth of this quantity of saccharine 

 (ground together in a mortar) over about 4 quarts of the dampened baits, 

 stirring to distribute the poison evenly. 



The runways, which are usually 4 to S inches beneath the surface, can be 

 located by means of a probe made of any strong handle an inch in diameter 

 and 36 inches long. One end should be bluntly pointed. Into the other should 

 be fitted a piece of three-eighths inch iron rod, protruding about 12 inches and 



1 If strychnine sulphate is used, dissolve in the boiling water before adding the starch ; 

 also dissolve the bicarbonate of soda before adding to the poisoned starch. Care is neces- 

 sary that the resulting mixture does not greatly exceed a pint. 



