20 



COMMON MAMMALS OK \V KSTKli X MONTANA. 



opened near a lire or where a person is smoking. Figure 11 shows 

 an excellent outfit for using bisulphid. 



CONCLUSIONS. 



The Columbian ground squirrel is (he worst rodent pesi in western 

 Montana, and is of especial importance in regions infested with 

 spotted fever, where it is the principal host of the younger stages of 

 (lie " fever tick." or wood tick. Tt is also the most difficult rodent in 

 the Northwest to control. The methods of eradication recommended 

 are early spring poisoning, followed at once by the systematic use of 

 traps or carbon bisulphid. 



Fig. 11. — Outlit for use in blsulphiding ground-squirrel burrows. 



CHIPMUNKS. 



DISTRIBUTION. 



Several kinds of chipmunks occur in western Montana, but they 

 are so nearly alike in appearance and habits that for the purposes of 

 this work no distinction is made between them. (Fig. 12.) Although 

 chipmunks arc not nearly so important as are Columbian ground 

 squirrels, they have a very definite relation both to agriculture and 

 to spot ted lever. 



AS TICK HOSTS. 



Probably more young wood ticks feed on chipmunks than on any 

 other kind of animal except Columbian ground squirrels. Of about 

 1D0 examined during 1910 and 1911, many were found to be tick 

 infested and some carried 50 or more seeds or nymphs. Chipmunks 

 occur commonh 7 around unoccupied log cabins, in stone and rail 

 fences, and in pastures where there is more or less brush and fallen 



484 



