6 



MAMMALS IN THEIR RELATION TO SPOTTED FEVER. 



fetida, and musk or beaver castor, are recommended for trapping. 

 For poisoning, pure sulphate of strychnine should be used in gelatin 

 capsules, 3-grain capsules for wolves and 2-grain capsules for coyotes. 



WOODCHUCKS. 



Woodchucks are so easily trapped and shot that persistent effort 

 only is needed to rid a locality of them. Very little is known in 

 regard to baits and poisons for this animal. It is believed that green 

 corn or carrots treated with the standard strychnine-starch solution 

 will prove effective. AMien woodchuck burrows are made in the soil, 

 and not among rocks, carbon bisulphid is the most certain remedy. 

 (For method of application see below.) 



COLUMBIAN GROUND SQUIRIIEL. 



These squirrels feed so largely on green vegetation during the 

 summer that they are difficult to poison. They take poisoned grain, 

 however, freely on their first appearance in spring when green food 

 is scarce and in August just before entering hibernation. The best 

 results have been obtained with the folloAving bait : 



Clean oats 8 quarts. 



Strychnine sulphate 1 ounce. 



Saccharin ^ tea spoonful. 



Thin starch solution 2i quarts. 



Dampen the oats with hot water and drain after a few minutes. 

 Dissolve the strychnine in the hot starch solution; mix in the sac- 

 charin. Apply to dampened oats and allow to stand at least 48 

 hours. Spread and dry. Distribute early in morning, scattering lib- 

 erally about squirrel holes. 



In cultivated lands trapping these squirrels with the No. 1 steel 

 trap by both " hole " and " surface " sets is very effective. Traps 

 should be visited at least twice a day to prevent unnecessary suffering 

 of trapped animals. 



Early in the season before the ground dries the use of carbon 

 bisulphid as given in Circular 76 is highly recommended. 



Crude carbon bisulphid, suitable for killing ground squirrels, 

 prairie dogs, and other burrowing animals, costs about 8 cents per 

 pound in 50-pound carboys or drums. It is a volatile liquid 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 : 



Half tablespoonful of crude bisulphid should be poured on a piece 

 of cotton waste or other absorptive material ; this should be pushed as 

 far as possible down the burrow and the opening closed immediately. 



[Cir. 82] 



