20 



FARMERS BULLETIN 932. 



squirrels, chipmunks, and perhaps some species of native mice not 

 already mentioned. Muskrats are valuable fur animals and should 

 not be destroyed unless they are doing material damage not other- 

 wise preventable. They are easily trapped or may be poisoned by 

 feeding them pieces of carrot, sweet apple, or sweet potato in which 

 strychnin has been placed. 



Mountain-beavers in the United States are restricted to the coastal 

 region of Washington, Oregon, and California, and to the Sierra 

 Nevada in the last-named State. Their habitat does not often bring 

 them in contact with agriculture, but in western Washington consid- 

 erable complaint of 

 their depredations on 

 crops, particularly 

 small fruits, has been 

 made. The animals 

 may be readily poi- 

 soned with apples in 

 which strychnin has 

 been placed. 



Squirrels, chip- 

 munks, and native 

 mice not previously 

 mentioned rarely do 

 serious damage. If 

 any become trouble- 

 some locally, shoot- 

 ing, trapping, or the 

 use of poisons herein recommended for other rodents will prove 

 satisfactory means of relief. 



INTRODUCED RODENTS. 



The house mouse and three kinds of rats are the only rodent pests 

 in North America not native to the country. They are our most 

 injurious rodents, however, and probably inflict greater losses than 

 do all the native species combined. 1 



House mice are easily trapped or poisoned, but poison is not suited 

 for use in occupied dwellings. Traps, however, are sufficiently ef- 

 fective for clearing the premises of these pests. The ordinary small 

 guillotine traps are recommended. They should be set as lightly as 

 possible and baited with oatmeal (rolled oats). A few grains should 

 be placed on the trigger pan and a little more in the vicinity and 

 close to the trap. Persistent trapping will soon clear an ordinary 

 dwelling of mice. 



1 For a full discussion of these rodents, see Farmers' Bulletin 806, " House Rats and 

 Mice," 1017. 



B 16902 



FIG. 15. Mountain-beaver, or sewellel, a pest in parts of 

 the Northwest. 



