,transcriber's ,note3 ,every effort has been made to replicate this text as faithfully as possible4 ,italic text has been marked with underscores4 ,,united ,,states ,,department ,,of ,,agriculture ,,farmers' ,,bulletin ,,washington1 ,d4 ,c4 #fgj ,,june #c1 #aiae4 ,contribution from the ,bureau of ,biological ,survey1 ,henry ,w4 ,henshaw1 ,chief4 ,,field ,,mice ,,as ,,farm ,,and ,,orchard ,,pests4 ,by ,d4 ,e4 ,,lantz1 ,assistant ,biologist4 ,,note4--,this bulletin describes the habits1 geographic distribution1 and methods of destroying meadow mice and pine mice1 and discusses the value of protecting their natural enemies among mammals1 birds1 and reptiles4 ,it is for general distribution4 ,,introduction4 ,the ravages of short-tailed field mice in many parts of the ,united ,states result in serious losses to farmers1 orchardists1 and those concerned with the conservation of our forests1 and the problem of controlling the animals is one of considerable importance4 ,short-tailed field mice are commonly known as meadow mice1 pine mice1 and voles2 locally as bear mice1 buck-tailed mice1 or black mice4 ,the term includes a large number of closely related species widely distributed in the ,northern ,hemisphere4 ,over #ej species and races occur within the ,united ,states and nearly #dj other forms have been described from ,north ,america4 ,old ,world forms are fully as numerous4 ,for the purposes of this paper no attempt at classification is required1 but two general groups will be considered under the names meadow mice and pine mice4 ,these two groups have well-marked differences in habits1 and both are serious pests wherever they inhabit regions of cultivated crops4 ,under the term meadow mice#a are included the many species of voles that live chiefly in surface runways and build both subterranean and surface nests4 ,under the term pine mice#b are included a few forms that1 like moles1 live almost wholly in underground burrows4 ,pine mice may readily be distinguished from meadow mice by their shorter and smoother fur1 their red-brown color1 and their molelike habits4 7,see fig4 #a47 #a ,genus ,microtus4 #b ,genus ,pitymys4 ,illustration3 ,,fig4 #a4--;,field mice3 a1 ,meadow mouse2 b1 pine mouse4 ,,meadow ,,mice4 ,meadow mice inhabit practically the whole of the ,northern ,hemisphere-- ,america1 north of the ,tropics2 all of ,europe1 except ,ireland2 and ,asia1 except the southern part4 ,in ,north ,america there are few wide areas except arid deserts free from meadow mice1 and in most of the ,united ,states they have at times been numerous and harmful4 ,the animals are very prolific1 breeding several times a season and producing litters of from #f to #aj4 ,under favoring circumstances1 not well understood1 they sometimes produce abnormally and become a menace to all growing crops4 ,plagues of meadow mice have often been mentioned in the history of the ,old ,world1 and even within the ,united ,states many instances are recorded of their extraordinary abundance with accompanying destruction of vegetation4 ,the runs of meadow mice are mainly on the surface of the ground under grass1 leaves1 weeds1 brush1 boards1 snow1 or other sheltering litter4 ,they are hollowed out by the animals' claws1 and worn hard and smooth by being frequently traversed4 ,they are extensive1 much branched1 and may readily be found by parting the grass or removing the litter4 ,the runs lead to shallow burrows where large nests of dead grass furnish winter retreats for the mice4 ,summer nests are large balls of the same material hidden in the grass and often elevated on small hummocks in the meadows and marshes where the animals abound4 ,the young are brought forth in either underground or surface nests4 ,meadow mice are injurious to most crops4 ,they destroy grass in meadows and pastures2 cut down grain1 clover1 and alfalfa2 eat grain left standing in shocks2 injure seeds1 bulbs1 flowers1 and garden vegetables2 and are especially harmful to trees and shrubbery4 ,the extent of their depredations is usually in proportion to their numbers4 ,thus1 in the lower ,humboldt ,valley1 ,nevada1 during two winters 7#aijf-h7 these mice were abnormally abundant1 and totally ruined the alfalfa1 destroying both stems and roots on about #ah1jjj acres and entailing a loss estimated at fully #bej1jjj4 ,when present even in ordinary numbers meadow mice cause serious injury to orchards and nurseries4 ,their attacks on trees are often made in winter under cover of snow1 but they may occur at any season under shelter of growing vegetation or dry litter4 ,the animals have been known almost totally to destroy large nurseries of young apple trees4 ,it was stated that during the winter of #aija-b nurserymen near ,rochester1 ,n4 ,y41 sustained losses from these mice amounting to fully #ajj1jjj4 ,older orchard trees sometimes are killed by meadow mice4 ,in ,kansas in #aijc the writer saw hundreds of apple trees1 #h to #aj years planted1 and #d to #f inches in diameter1 completely girdled by these pests4 7,fig4 #b47 ,the list of cultivated trees and shrubs injured by these animals includes nearly all those grown by the horticulturist4 ,the ,biological ,survey has received complaints of the destruction of apple1 pear1 peach1 plum1 quince1 cherry1 and crab-apple trees1 of blackberry1 raspberry1 rose1 currant1 and barberry bushes1 and of grape vines2 also of the injury of sugar maple1 black locust1 ,osage orange1 sassafras1 pine1 alder1 white ash1 mountain ash1 oak1 cottonwood1 willow1 wild cherry1 and other forest trees4 ,illustration3 ,,fig4 #b4--;,apple tree killed by meadow mice4 ,in the ,arnold ,arboretum1 near ,boston1 ,mass41 during the winter of #aijc-d1 meadow mice destroyed thousands of trees and shrubs1 including apple1 juniper1 blueberry1 sumac1 maple1 barberry1 buckthorn1 dwarf cherry1 snowball1 bush honeysuckle1 dogwood1 beech1 and larch4 ,plants in nursery beds and acorns and cuttings in boxes were especial objects of attack4 ,the injury to trees and shrubs consists in the destruction of the bark just at the surface of the ground and in some instances for several inches above or below4 ,when the girdling is complete and the cambium entirely eaten through1 the action of sun and wind soon completes the destruction of the tree4 ,if the injury is not too extensive prompt covering of the wounds will usually save the tree4 ,in any case of girdling heaping up fresh soil about the trunk so as to cover the wounds and prevent evaporation is recommended as the simplest remedy4 ,to save large and valuable trees bridge grafting may be employed4 ,,pine ,,mice4 ,pine mice occur over the greater part of eastern ,united ,states from the ,hudson ,river ,valley to eastern ,kansas and ,nebraska and from the ,great ,lakes to the ,gulf of ,mexico4 ,inhabitants chiefly of forested regions1 they are unknown on the open plains4 ,ordinarily they live in the woods1 but are partial also to old pastures or lands not frequently cultivated4 ,from woods1 hedges1 and fence rows they spread into gardens1 lawns1 and cultivated fields through their own underground tunnels or those of the garden mole4 ,the tunnels made by pine mice can be distinguished from those made by moles only by their smaller diameter and the frequent holes that open to the surface4 ,while the mole feeds almost wholly upon insects and earthworms1 and seldom eats vegetable substances1 pine mice are true rodents and live upon seeds1 roots1 and leaves4 ,their harmful activities include the destruction of potatoes1 sweet potatoes1 ginseng roots1 bulbs in lawns1 shrubbery1 and trees4 ,they destroy many fruit trees in upland orchards and nurseries 7fig4 #c74 ,the mischief they do is not usually discovered until later1 when harvest reveals the rifled potato hills or when leaves of plants or trees suddenly wither4 ,in many instances the injury is wrongly attributed to moles whose tunnels invade the place or extend from hill to hill of potatoes4 ,the mole is seeking earthworms or white grubs that feed upon the tubers1 but mice that follow in the runs eat the potatoes themselves4 ,illustration3 ,,fig4 #c4--,root and trunk of apple tree from ,laurel1 ,md41 gnawed by pine mice4 ,pine mice feed to some extent outside their burrows1 reaching the surface through the small openings made at frequent intervals in the roofs of the tunnels4 ,in their forays they rarely go more than a few feet from these holes4 ,most of their food is carried under ground1 where much is stored for future consumption4 ,while they differ little from meadow mice in general food habits1 their surroundings afford them a larger proportion of mast4 ,they are less prolific than meadow mice1 but this is more than made up for in the fact that in their underground life they are less exposed to their enemies among birds and mammals4 ,like meadow mice1 they sometimes become abnormally abundant4 ,in the eastern part of the ,united ,states pine mice do more damage to orchards than do meadow mice1 partly because their work is undiscovered until trees begin to die4 ,the runs of meadow mice under grass or leaves are easily found and the injury they do to trees is always visible4 ,on the other hand1 depredations by pine mice can be found only after digging about the tree and exposing the trunk below the surface4 ,the roots of small trees are often entirely eaten off by pine mice1 and pine trees as well as deciduous forest trees1 when young1 are frequently killed by these animals 7fig4 #d74 ,illustration3 ,,fig4 #d4--,pine tree killed by pine mice4 ,,destroying ,,field ,,mice4 ,methods of destroying field mice or holding them in check by trapping and poisoning are equally applicable to meadow mice and pine mice4 ,,trapping4 ,if mice are present in small numbers1 as is often the case in lawns1 gardens1 or seed beds1 they may readily be caught in strong mouse traps of the guillotine type 7figs4 #e and #f74 ,these should be baited with oatmeal or other grain1 or may be set in the mouse runs without bait4 ,illustration3 ,,fig4 #e4--;,field mouse caught in baited guillotine trap4 ,illustration3 ,,fig4 #f4--;,field mouse caught in unbaited guillotine trap4 ,trapping has special advantages for small areas where a limited number of mice are present1 but it is also adapted to large areas whenever it is undesirable to lay out poison4 ,it is then necessary to use many traps and continue their use for several weeks4 ,if mice are moderately abundant1 from #ab to #bj traps per acre maybe used to advantage4 ,these should soon make decided inroads on the numbers of mice in an orchard if not practically to exterminate them4 ,for pine mice the tunnels should be excavated sufficiently to admit the trap on a level with the bottom4 ,a light garden trowel may be used for the necessary digging4 ,,poisoning4 ,on large areas where mice are abundant1 poisoning is the quickest means of destroying them1 and even on small areas it has decided advantages over trapping4 ,the following formula is recommended3 ,dry grain formula4--,mix thoroughly #a ounce powdered strychnine 7alkaloid71 #a ounce powdered bicarbonate of soda1 and #a_/h ounce 7or less7 of saccharine4 ,put the mixture in a tin pepper box and sift it gradually over #ej pounds of crushed wheat or #dj pounds of crushed oats in a metal tub1 mixing the grain constantly so that the poison will be evenly distributed4 ,dry mixing1 as above described1 has the advantage that the grain may be kept any length of time without fermentation4 ,if it is desired to moisten the grain to facilitate thorough mixing1 it would be well to use a thin starch paste 7as described below1 but without strychnine7 before applying the poison4 ,the starch soon hardens and fermentation is not likely to follow4 ,if crushed oats or wheat can not be obtained1 whole oats may be used1 but they should be of good quality4 ,as mice hull the oats before eating them1 it is desirable to have the poison penetrate the kernels4 ,a very thin starch paste is recommended as a medium for applying poison to the grain4 ,prepare as follows3 ,wet grain formula4--,dissolve #a ounce of strychnia sulphate in #b quarts of boiling water4 ,dissolve #b tablespoonfuls of laundry starch in #a_/b pint of cold water4 ,add the starch to the strychnine solution and boil for a few minutes until the starch is clear4 ,a little saccharine may be added if desired1 but it is not essential4 ,pour the hot starch over #a bushel of oats in a metal tub and stir thoroughly4 ,let the grain stand overnight to absorb the poison4 ,the poisoned grain prepared by either of the above formulas is to be distributed over the infested area1 not more than a teaspoonful at a place1 care being taken to put it in mouse runs and at the entrances of burrows4 ,to avoid destroying birds it should whenever possible be placed under such shelters as piles of weeds1 straw1 brush1 or other litter1 or under boards4 ,small drain tiles1 #a #a_/b inches in diameter1 have sometimes been used to advantage to hold poisoned grain1 but old tin cans with the edges bent nearly together will serve the same purpose4 ,chopped alfalfa hay poisoned with strychnine was successfully used to destroy meadow mice in ,nevada during the serious outbreak of the animals in #aijg-h4 ,one ounce of strychnia sulphate dissolved in #b gallons of hot water was found sufficient to poison #cj pounds of chopped alfalfa previously moistened with water4 ,this bait1 distributed in small quantities at a place1 was very effective against the mice1 and birds were not endangered in its distribution4 ,for poisoning mice in small areas1 as lawns1 gardens1 seed beds1 vegetable pits1 and the like1 a convenient bait is ordinary rolled oats4 ,this may be prepared as follows3 ,dissolve #a_/af ounce of strychnine in #a pint of boiling water and pour it over as much oatmeal 7about #b pounds7 as it will wet4 ,mix until all the grain is moistened4 ,put it out1 a teaspoonful at a place1 under shelter of weed and brush piles or wide boards4 ,the above poisons are adapted to killing pine mice1 but sweet potatoes cut into small pieces have proved even more effective4 ,they keep well in contact with soil except when there is danger of freezing1 and are readily eaten by the mice4 ,the baits should be prepared as follows3 ,potato formula4--,cut sweet potatoes into pieces about as large as good-sized grapes4 ,place them in a metal pan or tub and wet them with water4 ,drain off the water and with a tin pepper box slowly sift over them powdered strychnine 7alkaloid preferred71 stirring constantly so that the poison is evenly distributed4 ,an ounce of strychnine should poison a bushel of the cut bait4 ,the bait1 whether of grain or pieces of potato1 may be dropped into the pine-mouse tunnels through the natural openings or through holes made with a piece of broom handle or other stick4 ,bird life will not be endangered by these baits4 ,,cultivating ,,the ,,land4 ,thorough cultivation of fields and the elimination of fence rows between them is the most effective protection against field mice4 ,cultivation destroys weeds and all the annual growths that serve as shelter for the animals4 ,this applies equally well to orchards and nurseries4 ,clean tillage and the removal from adjoining areas of the weeds and grass that provide hiding places for mice will always secure immunity to trees from attacks of the animals4 ,,protecting ,,natural ,,enemies ,,of ,,mice4 ,field mice are the prey of many species of mammals1 birds1 and reptiles4 ,unfortunately1 the relation that exists between the numbers of rodents and the numbers of their enemies is not generally appreciated2 otherwise the public would exercise more discrimination in its warfare against carnivorous animals4 ,it is the persistent destruction of these1 the beneficial and harmful alike1 that has brought about the present condition of growing scarcity of predacious mammals and birds and corresponding increase of rodent pests of the farm1 especially rats and mice4 ,the relation between effect and cause is obvious4 ,among the mammalian enemies of meadow and pine mice are coyotes1 wildcats1 foxes1 badgers1 raccoons1 opossums1 skunks1 weasels1 shrews1 and the domestic cat and dog4 ,among birds1 their enemies include nearly all the hawks and owls1 storks1 ibises1 herons1 cranes1 gulls1 shrikes1 cuckoos1 and crows4 ,among their reptilian foes are black snakes and bull snakes4 ,not all these destroyers of mice are more beneficial than harmful1 but the majority are1 and warfare against them should be limited to the minority that are more noxious than useful4 ,,owls ,,and ,,field ,,mice4 ,owls as destroyers of mice are deserving of special mention4 ,not one of our ,american owls1 unless it be the great horned owl1 is to be classed as noxious4 ,especially beneficial are the short-eared1 long-eared1 screech1 and barn owls4 ,all these prey largely upon field mice1 and seldom harm birds4 ,unfortunately1 the short-eared and barn owls1 which are the more useful species1 are not plentiful in the sections most seriously infested by field mice4 ,the short-eared owl1 while widely distributed1 is not abundant1 except locally1 within the ,united ,states1 but wherever field mice become excessively numerous these owls usually assemble in considerable numbers to prey upon them4 ,examinations of stomachs of these owls show that fully three-fourths of their food consists of short-tailed field mice4 ,the barn owl is rather common in the southern half of the ,united ,states and breeds as far north as the forty-first parallel of latitude4 ,that mice form the chief diet of this bird has been demonstrated by ,dr4 ,a4 ,k4 ,fisher1 of the ,biological ,survey1 through examination of stomachs of many barn owls and also of large numbers of pellets 7castings from their stomachs7 found under their roosts4 ,in #a1bdg barn-owl pellets collected in the towers of the ,smithsonian ,building in ,washington1 ,d4 ,c41 he found #a1iia skulls of short-tailed field mice1 #fef of the house mouse1 #baj of the common rat1 and #adg of other small rodents and shrews4 ,very few remains of birds were found4 ,figure #g illustrates the contents of some of these pellets4 ,illustration3 ,,fig4 #g4--;,field-mouse skulls taken from pellets found under owl roost in ,smithsonian tower1 ,washington1 ,d4 ,c4 ,in #cfj pellets of the long-eared owl ,dr4 ,fisher found skulls of #cgd small mammals1 of which #cdi were meadow mice4 ,stomach examinations give similar testimony to the usefulness of this bird4 ,the common screech owl1 in addition to feeding mainly upon mice1 destroys also a good many ,english sparrows4 ,its habit of staying in orchards and close to farm buildings makes it especially useful to the farmer in keeping his premises free from both house and field mice4 ,,washington3 ,,government ,,printing ,,office3 #aiae