1 62 ECONOMIC MAMMALOGY 



step should be to eliminate their hiding places, such as piles of old lum- 

 ber, brush heaps and weed patches. Their burrows should be plugged. 

 All foodstuffs should be kept in rat-proof rooms or containers. As 

 soon as crops are removed from fields and gardens there should be a 

 general clean-up. 12 Buildings should be rat^proofed by the free use 

 of cement, with tin or sheetiron re-enforcement of the bottoms of doors 

 and other places where gnawing is likely to occur. 13 All openings should 

 be closed so far as practicable, and necessary openings such as drain- 

 pipes and ventilators should be screened. Rats and mice may often be 

 cleared from infested buildings by fumigation, and trapping by experts 

 is an excellent method of disposing of them. For poisoning rats, barium 

 carbonate is preferred to strychnine by many, as rats are said to have 

 acquired remarkable resistance to the latter and perhaps to other 

 poisons. In the use of poison great care should of course always be 

 exercised to place it where it cannot be reached by children, or by 

 dogs or other valuable animals for which it is not intended. All ani- 

 mals are more easily caught or poisoned when food is scarce and they 

 are consequently hungry, hence another reason for keeping foodstuffs, 

 as well as garbage, where mice and rats cannot get them. 14 



Silver recommends deterrent odors (where no foods can be affected 

 thereby), such as flake napthaline in quantity, creosote, carbolic acid, 

 kerosene, oils of peppermint and wintergreen, sulphur, lime, lye and 

 copperas ; and for deodorizing when rats and mice have died in build- 

 ings he recommends, as best, a few teaspoonfuls of lysol, dropped 

 into their holes or other suspected places, though zinc chloride is also 

 good. 15 As in campaigns against other pests, community cooperation 

 is often desirable, in order to get rid of sources of infestation. 



In western states where woodchucks are not overly abundant they 

 have been successfully controlled by use of poisons placed in their 



in relation to stock, game and national forest reserves, U. S. Forest Service Bull. 

 No. 20, 1905. Lantz, Coyotes in their economic relations, U. S. Biol. Surv. Bull. No. 

 20, 1905; The relations of coyotes to stock raising in the West, Farmers' Bull. No. 

 226, 1905. Simmons, Sheep-killing dogs, Farmers' Bull. No. 1268, 1929. 



12 Birdseye, Farmers' Bull., No. 484, 1912. Burnett, Office Colorado State Entom. 

 Circular No. 18, 1916. 



13 Lantz, House rats and mice, Fanners' Bull., No. 806, 1917 ; The house rat : The 

 most destructive animal in the world, Yearbook U. S. Dept. Agric. for 1917, pp. 335- 

 351. Use of concrete on the farm, Farmers' Bull., No. 461. 



14 Silver, How to get rid of rats, Farmers' Bull., No. 1302, 19^3. Lantz, Methods 

 of destroying rats, Farmers' Bull, No. 297, 1907; U. S. Biol. Surv. Bull. No. 33, 

 1909. Forbush, Rats and rat riddance, Massachusetts State Board of Agric., Econ. 

 Biol., Bull. No. i, 1915 ; also in 62nd Ann. Kept. Dice, Journ. Mammalogy, iv, 188- 

 189, 1923- 



15 Silver, Rat control, Farmers' Bull., No. 1533, 1927. 



