,issued ,may #ca1 #aijg4 ,u4 ,s4 ,,department ,,of ,,agriculture4 ,,farmers' ,,bulletin #big4 ,,methods ,,of ,,destroying ,,rats4 ,,by ,,david ,e4 ,,lantz1 ,assistant1 ,bureau of ,biological ,survey4 ,illustration ,,washington3 ,,government ,,printing ,,office4 #aijg4 ,transcriber's ,note3 ,words surrounded by tildes1 like this signifies words in bold4 ,words surrounded by underscores1 like this1 signifies words in italics4 ,,letter ,,of ,,transmittal4 ,u4 ,s4 ,,department ,,of ,,agriculture1 ,,bureau ,,of ,,biological ,,survey1 ,washington1 ,d4 ,c41 ,may #ae1 #aija4 ,,sir3 ,i have the honor to transmit herewith for publication ,farmers' ,bulletin ,no4 #big1 containing concise directions for the destruction of rats1 prepared by ,david ,e4 ,lantz1 an assistant in this ,bureau4 ,the damage done by these rodents1 both in cities and in the country1 is enormous1 and the calls for practical methods of destroying them are correspondingly numerous and urgent4 ,it is believed that by following the directions here given the numbers of this pest can be greatly reduced and the losses from them proportionally diminished4 ,respectfully1 ,c4 ,,hart ,,merriam1 ,chief1 ,biological ,survey4 ,,hon4 ,,james ,,wilson1 ,secretary of ,agriculture4 ,,contents4 ,page4 ,introduction #c ,methods of destroying rats #d ,poisoning #d ,trapping #e ,use of ferrets and dogs #f ,fumigation #g ,rat-proof construction #g ,natural enemies of rats #h ,conclusions #h ,,illustration4 ,page4 ,,fig4 #a4--,method of baiting guillotine trap #f ,,methods ,,of ,,destroying ,,rats4 ,,introduction4 ,the brown or ,norway rat 7,mus norvegicus7 is the worst mammal pest in the ,united ,states1 the losses from its depredations amounting to many millions of dollars yearly--to more1 indeed1 than the losses from all other injurious mammals combined4,a ,in addition to its destructive habits1 this rat is now known to be an active agent in disseminating infectious diseases1 a fact which renders measures for its destruction doubly important4 ,footnote ,a3 ,several species of rats are known as house rats1 including the black rat 7,mus rattus71 the roof rat 7,mus alexandrinus71 and the brown rat 7,mus norvegicus74 ,of these1 the last is the commonest and most widespread in this country4 ,not one of these species is a native1 but all were imported from the ,old ,world4 ,as their habits in general are similar1 the instructions given in the bulletin apply alike to all4 ,introduced into ,america about the year #agge1 the brown rat has supplanted and nearly exterminated its less robust relative1 the black rat1 and despite the incessant warfare of man has extended its range and steadily increased in numbers4 ,its dominance is due to its great fecundity and its ability to adapt itself to all sorts of conditions4 ,it breeds three or four times a year and produces from #f to #ab1 and even more1 young at a litter4 ,young females breed when only #d or #e months old4 ,the species is practically omnivorous1 feeding upon all kinds of animal and vegetable matter4 ,it makes its home in the open field1 the hedge row1 and the river bank1 as well as in stone walls1 piers1 and all kinds of buildings4 ,it destroys grains when newly planted1 while growing1 and in the shock1 stack1 mow1 crib1 granary1 mill1 elevator1 or ship's hold1 and also in the bin and feed trough4 ,it invades store and warehouse and destroys fur1 laces1 silks1 carpets1 leather goods1 and groceries4 ,it attacks fruits1 vegetables1 and meats in the markets1 and destroys by pollution ten times as much as it actually eats4 ,it carries disease germs from house to house and bubonic plague from city to city4 ,it causes disastrous conflagrations2 floods houses by gnawing lead water pipes2 ruins artificial ponds and embankments by burrowing2 destroys the farmers' pigs1 eggs1 and young poultry2 eats the eggs and young of song and game birds2 and damages foundations1 floors1 doors1 and furnishings of dwellings4 ,,methods ,,of ,,destroying ,,rats4 ,a compilation of all the methods of destroying rats practiced in historic times would fill a volume4 ,unfortunately1 the greater number of them are worthless or impracticable4 ,few have more than temporary effect upon their numbers1 and even the best of them fail unless persistently applied4 ,conditions vary so much that no one method of dealing with this pest is applicable in all cases4 ,among the more important measures to be recommended for actively combating the brown rat are3 7#a7 ,poisons2 7#b7 traps2 7#c7 ferrets2 7#d7 fumigation1 and 7#e7 rat-proof construction of buildings4 ,,poisoning4 ,barium ,carbonate4--,one of the cheapest and most effective poisons for rats and mice is barium carbonate1 or barytes4 ,this mineral has the advantage of being without taste or smell2 and1 in the small quantities used in poisoning rats and mice1 is harmless to larger animals4 ,its action on rodents is slow1 but reasonably sure1 and has the further advantage that the animals before dying1 if exit be possible1 usually leave the premises in search of water4 ,its employment in houses1 therefore1 is rarely followed by the annoying odor which attends the use of the more virulent poisons4 ,the poison may be fed in the form of a dough made of one-fifth barytes and four-fifths meal1 but a more convenient bait is ordinary oatmeal1 with about one-eighth of its bulk of barytes1 mixed with water into a stiff dough2 or the barytes may be spread upon bread and butter or moistened toast4 ,the prepared bait should be placed in rat runs1 a small quantity at a place4 ,if a single application of the poison fails to drive all rats from the premises1 it should be repeated with a change of bait4 ,strychnine4--,strychnine is a more virulent poison1 but its action is so rapid that the animals often die upon the premises1 a circumstance which prohibits its use in occupied dwellings4 ,elsewhere strychnine may be employed with great success4 ,dry strychnine crystals may be inserted in small pieces of raw meat1 ,vienna sausage1 or toasted cheese1 and these placed in the rat runs2 or oatmeal may be wet with a strychnine sirup1 and small quantities laid out in the same way4 ,strychnine sirup is prepared as follows3 ,dissolve a half ounce of strychnia sulphate in a pint of boiling water2 add a pint of thick sugar sirup and stir thoroughly4 ,a smaller quantity of the poison may be prepared with a proportional quantity of water4 ,in preparing the bait it is necessary that all the oatmeal should be moistened with sirup4 ,wheat is the most convenient alternative bait4 ,it should be soaked over night in the strychnine sirup4 ,other ,poisons4--,the two poisons most commonly used for rats and mice are arsenic and phosphorus1 nearly all commercial preparations containing one or the other as a basis4 ,while experiments prove that rats have great powers of resistance to arsenic1 it may sometimes be used advantageously as an alternative poison4 ,preparations of phosphorus sold by druggists are often too weak to be effective2 and home-made mixtures1 when of sufficient strength1 are dangerous1 as rats may carry the baits into walls or crannies and thus cause fires4 ,for these and other reasons the ,biological ,survey does not recommend preparations containing phosphorus4 ,poison in the ,poultry ,house4--,for poisoning rats in buildings and yards occupied by poultry1 the following method is recommended3 ,two wooden boxes should be used1 one considerably larger than the other1 and each having two or more holes in the sides large enough to admit rats4 ,the poisoned bait should be placed on the bottom and near the middle of the larger box1 and the smaller box should then be inverted over it4 ,rats thus have free access to the bait1 but fowls are excluded4 ,,trapping4 ,trapping1 if persistently followed1 is one of the most effective methods of destroying rats4 ,the improved modern traps with a wire fall released by a baited trigger and driven by a coiled spring have marked advantages over the old forms1 and many of them may be used at the same time4 ,these traps1 sometimes called guillotine traps1 are of many designs1 but the more simply constructed are to be preferred4 ,probably those made entirely of metal are the best1 as they are less likely to absorb and retain odors4 ,in illustration of the effectiveness of traps1 it may be related that a year or two ago a large department store in ,washington experienced heavy losses of gloves1 lace curtains1 and other merchandise from rat depredations4 ,for several months the damages amounted to from #aj to #cj nightly4 ,after many unsuccessful attempts to abate the nuisance the managers were advised to try the improved traps4 ,as a result #acf rats were killed during the first twenty nights1 when the losses practically ceased1 and the method has been continued in the store ever since with satisfactory results4 ,guillotine traps should be baited with small pieces of ,vienna sausage 7,wienerwurst7 or bacon4 ,the trigger wire should be bent inward to bring the bait into proper position to permit the fall to strike the rat in the neck1 as shown in the illustration 7fig4 #a74 ,other excellent baits for rats are oatmeal1 toasted cheese1 toasted bread 7buttered71 and sunflower or pumpkin seeds4 ,when seed1 grain1 or meal is used with a guillotine trap1 it may be placed on the trigger plate1 or the trigger wire may be bent outward and the bait sprinkled under it4 ,illustration3 ,,fig4 #a4--,method of baiting guillotine trap4 ,wire cage traps 7,french7 also are useful for catching rats1 but in the long run the kinds recommended above are much more effective4 ,while trapping1 all other food should be removed and the trap bait should be changed often4 ,rats are very suspicious1 and baits and traps should be handled as little as possible4 ,increased success may be secured both in trapping and poisoning if the rats are fed for a night or two with the kinds of food to be used for bait4 ,,use ,,of ,,ferrets ,,and ,,dogs4 ,a ferret is useful for the purpose of driving rats out of burrows and other hiding places so that dogs can capture them4 ,an experienced person with dogs and ferrets trained to work together can kill many rats when they are numerous4 ,but the amateur ferreter is likely to be greatly disappointed4 ,in the rice fields of the far ,east the natives build numerous piles of brush and rice straw and leave them for several days until many rats have taken shelter in them4 ,a portable bamboo inclosure several feet in height is then set up around each pile in succession and the straw and brush are thrown out over the top while dogs and men kill the trapped rodents4 ,large numbers are killed in this way1 and the plan with modifications may be utilized in ,america with satisfactory results4 ,a wire netting of fine mesh may be used for the inclosure4 ,the scheme is applicable at the removal of grain1 straw1 or hay stacks1 as well as brush piles4 ,,fumigation4 ,rats may be destroyed in their burrows in the fields1 and1 still more important1 in levees and rice-field dikes1 by the use of carbon bisulphid4 ,a wad of cotton or other absorbent material is saturated with the liquid and pushed into the burrow1 the opening being packed with soil to prevent escape of the gas4 ,all animals in the burrow are asphyxiated4 ,fumigation about buildings is not so effective1 as the gas can not readily be confined4 ,,rat-,,proof ,,construction4 ,the best way of excluding rats from buildings1 whether in the city or country1 is by the use of cement in construction4 ,as the advantages of this material are coming to be generally understood1 its use is rapidly extending to all kinds of building4 ,dwellings1 dairies1 barns1 stables1 chicken houses1 ice houses1 bridges1 dams1 silos1 tanks1 cisterns1 root-cellars1 hotbeds1 sidewalks1 and curbs are now often made wholly of concrete4 ,in constructing dwelling houses the additional cost of making the foundations rat-proof is slight as compared with the advantages4 ,the cellar walls should have concrete footings and the walls themselves be laid in cement mortar4 ,the cellar floor should be of medium rather than lean concrete1 and all water and drain pipes should be surrounded with concrete4 ,even an old cellar may be made rat-proof at comparatively small expense4 ,rat holes may be permanently closed by a mixture of cement1 sand1 and broken glass or sharp bits of stone4 ,rat-proof granaries1 corncribs1 and poultry houses may be constructed by a liberal use of concrete in the foundations and floors4 ,rats1 mice1 and sparrows may be excluded from corncribs by the use of either an inner or an outer covering of fine-mesh wire netting sufficiently heavy to resist the teeth of rats4 ,the common custom of setting corncribs upon posts with inverted pans at the top often fails because the posts are not long enough to insure that the lower cracks of the structure are beyond jumping reach of rats4 ,the posts should project at least #c feet above the surface of the ground4 ,,natural ,,enemies ,,of ,,rats4 ,the value of carnivorous mammals and the larger birds of prey in destroying rats should be more fully recognized1 especially by the farmer and the game preserver4 ,chief among the animals that are useful in destroying these rodents are the fox1 skunk1 and weasel1 and the larger species of owls and hawks4 ,rats destroy more poultry and game1 both eggs and young chicks1 than all the birds and wild mammals named combined1 yet some of our most useful birds of prey and carnivorous mammals are persecuted almost to the point of extinction4 ,an enlightened public sentiment should cause the repeal of all bounties on these animals and afford protection to the majority of them4 ,,conclusions4 ,by the persistent use of traps1 occasional resort to poison1 and the exercise of forethought in the construction of farm buildings so as to minimize the opportunities for harborage1 farmers and others may prevent the greater part of the loss and annoyance they now experience from rat depredations4 ,the same statement applies in great measure to city and village conditions4 ,hence cooperation in the warfare on rats is particularly important and can not be too strongly urged4