ever, when calciuin' cyanide is used in rainy weather* Temperature is not 

 a limiting factor, provided the snakes are not hibernating. The quantity 

 of calcium cyanide necessary to kill snakes in a den or cave depends on 

 the number of cubic feet of air space to be saturated with the poisonous 

 gas. In generrJ., it appears that 2 ounces of cyanide will liberate a deadly 

 concentration of gas in a space not exceeding 5 cubic feet, provided there 

 is no leakage. Calcium cyanide is offered for sale in 1 and 5 pound c^ns,. 

 A list of dealers will be furnished by the Fish and 'Jildlife Service on 

 request, ' 



If snakes prove troublesome by entering houses or buildingsvused for 

 workshops and storage and the buildin^o arc so constructed that they can be 

 tightly closed or sc;aled up for sho:.'t T>:^riod, fumigation with hydrocyanic- 

 acid gas is recommended. Full instructions for using this gas are contain'- 

 ed in Circular 369, which may bo obtained on application to the Bureau of 

 KntOiTiology and Plant '"quarantine. United States Department of Agriculture, 

 Washington, D, C. Buildings in which hydrocyanic-acid is used must be va.^- 

 cated for a day or more, for this gas is e:5<:trem.ely deadly and vdll destroy 

 every living thing vdthin the building, 



OTIFR I^THODS OF ERADICATinN 



In spring entire colonies of rattlesnakes and copperheads can be des-^ 

 troyed if the place where they have v/intered is discovered. Here in the 

 early days of March and April they emerge to lie in the sun and are so 

 sluggish that they may easily be dispatched with clubs. Later on in spring 

 they spread out to the hillsides and fields in search of mice, small birds, 

 and other proy. where conditions permit, number of hogs, if given free 

 run of snake-infested areas, will greatly reduce the sn ike population. Ex- 

 cept by this method or by gasing, control measures cannot be applied against 

 snakes on a large scale, -nd each reptile has to be dealt v;ith individually. 



No successful appar tus for snaring snakes has ever been devised. It 

 is difficult to induce a snake to enter a trap, for it has no fixed trails 

 and lacks inquisitiveness. Some collectors have been able to capttre cer- 

 tain kinds of snakes, by tying '. small frog by one leg to a stake in suita- 

 ble surroundings. The snake swallows the frog and is held captive until 

 digestion dissolves the swallowed bait giving the trapper opportunity to 

 return and dispose of the snake. Another method is to dig pits three or 

 more feet deep v/ith vertica,! sides ajid place severr.l live frogs or mice 

 in themi for decoys. Such pits should not be made in any neighborhood v/here 

 either livestock or human beings are accustomed to travel^ Professional 

 collectors depend almost entirely on a forked stick or a pair of iron tongs, 

 3 or 4 feet in length, to capture snakes. 



A few snrjtcs like the blacksna.ke, ( Coluber constrictor ) and chicken 

 snakes ' ( Elaphe guadriyittata and '^lar-^he obsolota confinis ) enter poultry 

 houses and barns in search of eggs or young birds. Snakes kno^vn to feed 

 on eggs may sometim.es be killed by poisoned eggs. The m.ost satisfactory 

 method of preparing the bait is to m-'-ky a small hole in a fresh egg and 



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