Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. a United States Department of Agriculture Bureau of Biological Survey Wildlife Research and Management Leaf let BS-54 ANGE ep ra ie Sa eral 1). Oe te i .. Rev., December 19 ee RODENT CONTROL AIDED BY EMERGENCY CONSERVATION WORK By atenley P. Young, Chief, Division of Game Management Contents Page : ; Page MeSewvOrwmogemt Control. o . . < .« © © Gi@mtcrol work 1llustrated. 5 2) .ne 6 Federal, State, and local caoper- : PAGES NOLS! af Meal ts Gt aeiehlts. Wemnrm 14 EU Dido Pi aN Sea Ce nnn Wi Erounde Squat relksl es, Keele epee Meme Training of ®.C.W. crews . . ms POCKem GOMES Ne 1 Mail aie ny Yel eeneemlee) Timeliness of emergency aid. ...3: amAarOO eats We lect oh uel anna | Gam Horest and forage protection ...3: Rabbits amdunares. folie) i vale. meee FeGhetoeroston control - . .-...°. 4% el ee ae Le RELL ORS, ah ater Hmemples OL Denetits derived . . . 4: typical H.C. TW. erews < %) « "ml 8Se Safeguarding harmless species. .. 5: Need for Rodent Control The Emergency Conservation. Work Program has been of inestimable value in the control of prairie dogs, ground squirrels, pocket gophers, kengaroo rats, rabbits, and porcupines. The citizens of the West have been forced to carry on campeigns for the control of these rodents since the settlers first staked out claims. on the prairies. To the agricultural interests of the West the control of rodents is ag vital as is the proper spraying of trees through- out the East to prevent damage by insects. These small mammals cover the west- em ranges by countless thousands, and control is necessary if crops are to be grown. Rodent centrol is nothing new. Rezords indicate sage as early as 1808, strychnine ves shipped by boat around Cape Horn to the Sante Barbare Mission, Calif., in order that the early settlers might kill oft. ‘the ground squirrels. A constant fight has been waged ever since, but. unfortunately, while the Land- owners were willing to finance the. killins of squirrels sn their own holdings, the Federal Government provided inadequate funds to take care of the vast areas of public domain, national forests, Indian reservations, and other Federal hold- ings. Federal, State, and Local Cooperation When the Emergency Conservation Work Program came into being, the Forest Service, the Bureau of Indian Affairs, the Bureau of Reclamation, the Division ef Grazing, and the Bureau of Biological Survey took the opportunity to treat a vast acreage that would have been treated years ago had funds permitted. During tne three fiscal years 1934 to 1936 a total of almost 20,000,000 acres had been covered by #.C.W. for the control of these various rodent pests. On the statute books of several Western States rodent-control laws provide that land- owners may establish rodent-control districts wherein all lands are treated simultancously by paid crews working under the supervision of the Biological Survey. Never before the E.C.W. program were there adequate Federal funds to make these laws effective by taking proper care of infested public lands adja- cent to privete holdings. The most concrete proof of the necessity of rodent control is found in the amount of money expended by private individuals throughout the West for this purpose. The Federal Government, while owning as much as 60 percent of the land in many of the Western States, contributes only about 25 percent of the total cost of rodent-control operations. During the fiscal year 1936, States, counties, and private individuals experded $665,785 for the purpose, while the Biological Survey was able to exnend only $226,623 from regular appropria- tions. The E.0.. program afforded the first opportunity of somewhere near meeting the Federal Government's obligations to the citizens of the West in the matter of adequately controlling the rodent pests that breed and range on public lands and from these strongholds infest and reinfest adjacent private holdings. Rodent control is one of the most popular projects with E.C.%. enrollees themselves as well as with the local people benefited. In many cases, crew foremen supplied by the Survey took boys who would not work satisfactorily on any other type of project and made real hands of them on rodent-control crews. The boys likedto work in these crews, as it afforded them opportunity to be- come acquainted not only with methods of rodent control but with the various habits of wildlife as well. In order to employ proper methods and place all possible safeguards around poisoning operations for the protection of beneficial ard harmless spe- cies, the Biological Survey has insisted upon approving the appointments of all men employed on the supervision of rodent-control work for its various cooperat- ing agencies. This is for the reason that when poisoning campaigns are properly handled and carefully supervised, there is little danger of the accidental poison- ing of other animals. The records indicate that there have been practically no cases of destriction of other forms of life through the E.C.W. rodent-control program. Naturally, the supervisors not only must know rodent control but also must be acquainted with the habits and status of wildlife in general, and in hand- ling the crews they have imparted knowledge to the boys that will be of perma- nent benefit to them and to the Nation. Educational programs were provided as regularly as possible, in-order to tell the C.C.C. enrollees of various wildlife problems. The entire personnel of H.C... camps were shown films depicting the work of beavers, showing measures for the protection of elk, deer, ard other big-game animals, and portraying the need of sanc, sensible conservation methods, in order that the remnants of our fast-vanishirg forms of valuable wildlife might be preserved. Mimeographed leaflets on wildlife management studies were made up by district. agents of the Survey for the boys in order that they might be given as broad instructions as possible in the protection and preservation. of species that are an asset rather than a liability to man's interest. It has been the attempt of the Biclogical Survey to make the rodent-control project a field laboratory for the education of the enrollees in natural history and wildlife management, and the popularity of the project among the boys attests te the wisdom-of this course. In many camps more applications for places on rodent-control crews were received than there were places to fill. Timeliness of Emergency Aid Fortunately, the E.C.. prcegram came at the mcst opportune time. The extreme drought throughout the Jest had forced rodents from the open lands. into adjacent irrigated valleys and mountain meadows, where they became especially objectionable in their competition with livestock for the available forage. Livestock and rodents together, during dry periods, have in many places almost entirely denuded the surface soil of its vegetation. This has caused the begin- ning of sheet erosion in areas where there would still be ample forage for live- stock had it not beer for the excessive numbers of rodents. On many areas, grazing by livestock and rodents combined has practically eliminated the native grasses, and these are now being replaced with weeds and poisonous plants. Damage in some instances has amounted to at least 75 percent of the available forage, and the average loss has probably been approximately 25 percent. On some of the Indian reservations of the Southwest, the condition has been pitiful. On the Navajo Reservation, in particular, the Indians have car- ried on a losing fight against drought and rodents. It hes often been necessary for them to replant their corn three and four times a season, since kangaroo rats and other native rodents dig up the kemels as rapidly as they are planted. Prior to the spring of 1936, there had been four years of drought, and this, coupled with rodent damage, had reduced corn production to the point where the Indians had barely enough for the spring seeding. All were clamoring for aid, and in order to save their last crop of corn it was necessary to detail a fore- man with four or five E.C.W. Indians to go from fams to farm and eonduct rodent- contrel operations. Forest and Forage Protection The Forest Service is endeavoring to carry on a reforestation program throughout much of the cut-over area in the Lake States and the Pacific North- west. One of the chief problems to successful reforestation is the control of rodents, particularly the snowshoe hare. In the Olympic Forest in Washington, the snowshoe. hare has destroyed as much as 40 percent and damaged 70 percent of the Douglas fir seedlings. In Michigan and Wisconsin, it was necessary to carry on extensive rodent-control operations to permit the seedlings to survivee uch of this work would never have been possible but for E.C.V. help. a aN In the open area, jack rabbits have become a serious pest. The Biological Survey, in 1934, received a petition bearing the sizmatures of more than ¢,000 individuals of eastern Colorado, requesting Government aid in killing jack rab- bits, which were ravaging the meager stocks of forage left after drougnt. and wind had taken their tcll. The #orest Service recognized that rodent control would be essential if the Plains Shelterbelt prozram of planting trees from the Canadian border to Texas was to be effective, and in 1935 approximately one-tenth of its entire appropristion for the program was expended for rodest ccntrol under the super- Vision. of tne Biological Survey. Crews patrolled the planted areas constantly to prevent the gnawing of the seedlings by jack rabbits and pocket gophers. Aid _ in Erosion Control The permanent benefits accruing from the E.C.W. rodent-control program have been enormous from the standpoirzt of erosion control alone. An associate range examiner of the Forest Service has the following to say regarding the effect of rodents on erosion in the Boise watershed of Idaho: "Rodents, numerous and spreading over nearly 80 percent of the Boise watershed, have undoubtedly been responsible for no small part of the present erosion. ‘holly deperdent upon the herbeceous plants for their food supply, their tremendous rumbers, along with over-grazing by livestock and unfavorable climate, have been an important contributing factor in depleting this cover, and thus have greatly reduced the protection afforded the soil and subjected it the more to increased sheet erosion. Even light rains on rcdent-infested areas are likely to start cutting, which may develop into destructive gulley erosion because of the almost immediate accumulation of run-offs in the myriads of burrows and channels which these animals construct just under the surface of the soil. The control of rodents is vital to the successful operation of reclam- ation projects in the western third of the United States. Rodents, particu- larly pocket gophers, find the barks of irrigation canals an ideal location for their burrows and runways. These subterranean passageways frequently are the cause of serious breaks in canals, through which the flow of irrigation water is diverted and wasted to flood adjacent lands, destroying valuable crops, and indirectly ruining others by causing delays in delivery of water. Through the E.C.%. program, C.C.C. crews working under the direction of experienced foremen trained by the Biological Survey have greatly reduced this menace. In the past year alone half a million acres of canal banks and contiguous lands were treated by ©.C.C. rodent-control crews with a thoroughness that will be of lasting benefit to the nation's reclamation projects. Examples of Benefits Derived A few concrete examples will illustrate the great good that has resulted from the E.C.. rodent-control program. A group of farmers living at Spring- field, Idaho, suggested to the camp superintendent there that the jack rabbit {/ control work done by the E.C.7. crew during the summer of 1935 might pay the cost of the camp. It is estimated that not less than 600,000 rabbits were yA hae killed by this crew on public lands adjacent to farming areas between American Falls and iioreland, Idaho. The work afforded protection to not less tnan nalf @ million dollars worth of cultivated crops end to more than 75,000 acres of grazing lands, mae control work carried on by an #.C.W. crew near weber Lake, Celif., in 1943 has been responsible for a 50 percent comeback of the gress ona large mountain meadow, which had been made a dust heap because of pocket go- pher workings. Tne eee gophers had honeycombed tne surface of the ground, end sheep had trampled out most of the grass, wails livestock grazing nad been reduced to a negiizible figure. Whe restoration in two years was due primarily to the elimination cf the pocket gophers. To control prairie dogs in Cklanoma, ean area of 47,000 acres in Pawnee, Noole, end = Counties was treated through the medium of the #.C.W. ‘Tne Indian lands here are interspersed with private lands, and the landowners were unable to make any progress in a general clean up because there were insuffi- cient Federal funds to treat the Indian lands until the H.C.W. project afforded opportunity to carry on a systematic campaign over the entire area. A good pieee of work was accomplished, and this, in conjunction with water develop— ments, made the grass so much better over tuese old prairie dog towns in the spring of 1955 tnat the Indian Service officials at Pawnee received an increased rental of 25 cents an acre on their grazing lands. On areas where they received oO cents an acre in 1944, they received 75 cents in 1935, a direct increase in Teceipts to the Federal Treasury, Tne permenent benefit accruing to the Indians from #.C.W. rodent con- trol is summed up es follows by an Agricultural Extension agent of the Indian Service, at Anadarko, Oklahoma: "No little stress can be pleced upon the financial value of the rodent- control project to tne Indians. The indian enrollees received the labor pene- fit on both Tidian and deeded land throughout the reservation but still greater than the temporary labor relief, the Indian has received a lasting increase in the financial rental of his land. Due to such neavy prairie dog infestation of tne allotted land it hed become necessary to reduce the rental value of the gress jand infested. Now that tne prairie dogs have been controlled tne renta Value will be increased by approximately 10 cents or more per acre because tne pastures will regrass and the carrying capacity will be increased, In comparing this inerease in rental value with the cost ox: controlling the prairie cogs, the Indians will reap the financial benefit of tae Government expenditures in two or three years, Therefore, tnis project nas certainly been of utmost Value to the reservation and tne Extension Division in nelping tne Indian to help himself," Seteguerding Harmless Species See some persons uninformed as to tne need for rodent control end the methods followed by the Biological Survey in carrying on the work neve stated that control by use of poison and C.C.C. workers endangers tne existence of otner forms of wildlife. This, however, is not the case. The Biclogical Survey has studied rodent-control methods for more than twenty years and in this period it has developed the most scientific and selective poisons possible. Scien- tific investigetions conducted by the Bureau are pringing increasing knowledge of the habits of economically injurious species and of their physiological reaction to various baits, This nas mede it possible to usc more and more specific control methods and so to select, prepare, and exoose poison baits as not seriously to endanger animals otner than those for wnichn the baits are intended. when these scientific methods are carried out under direct super- vision of trained personnel, tne total numoer of beneficial species destroyed is negligible. Tne Biclogicel Survey is a conservetion organization and will undertake no work thet will be detrimental to any species of enimal not interfering too greatly witn tas interests of man. Those conversant with actual conditions in the range Stutes realize that if agriculture is to survive, the control of injurious rodents is as essential as is control of the corn borer, tne chinch bug, tne doll weevil, the grasshopper, the coddling moth, and numerous other agricultural pests. The Survey insists that in conducting work of tnis sort, the most carsiul supervision by trained tec.imicians must be given. All coop— erating agencies recognize the necessity for such supervision, and as a result @ most wortn-waile program nas been carried on curing the past tnrge fiscal years. Tne Biological Survey has entered into written cooperative understand— ings with the various governmental agencies under which rodent-—control activ— ities have been conducted. These wgreements place the responsibility for technically supervising all rodent-control activities in the nands of the Bureau, leaving the cooperating agencies responsible for administration. Control Work Illustrated The illustrations on the following pages tell better than would volumes of written words, tne story of rodent Gamage and of cooperative work to reduce this damage. PRAIRIE DOGS Four years experimental study in northern Arizona showed that prairie dogs destroy 60 percent of the wheat grass, 99 percent of the dropseed, and 83 percent of the grama grass, or 80 percent of the total potential annual production of forage. The possible destruction of four-fifths of the forage, or even a far smaller proportion, is serious enough at any time, but in periods of drought it is likely to be calamitous. The following pictures show typical prairie dog infestation. Prairie dog mounds on abandoned Indian farn, Southern Navajo Reservation, Arizona. @7= Area practically denuded of grass by prairie dogs - Mescalero Indian Reservation, New Mexico. Dogs on leash and tin cans rattling in the wind are some oe of the primitive methods employed by Indians in futile attempt to save crops from ravages of prairie dogs in the Southwest. eet Indian cornfield totally destroyed by prairie dogs. Cotton and corn fields damaged by prairie dogs in northwest Texase Side of basin denuded by prairie dogs - devastation being rapidly completed by erosion. Coohetopa Forest, Colorado. Prairie dogs prepare an ideal condition for the start of sheet erosion on hillsides by denudation of vegetative cover. Note lack of vegetation. Erosion once started is accelerated by other factors as shown on page ll. olle Interpreter explaining to Indian farmer in Arizona how to expose poisoned grain. The Indian, at the left, stated that he picked up 180 dead prairie dogs over an area estimated at about 200 acres around his 48 acre farme =1l20 GROUND SQUIRRELS Ground squirrel damage. Semidesert type country. | Note squirrel at mouth of burrow. E. C. We. ground squirrel control crew - Payette National Forest, Idaho. E. C. W. Ground squirrel burrows become waterways during @ rain and are the beginning of this type of erosione Papago Indian Reservation, Arizonae -14= POCKET GOPHERS Typical mountain range land, heavily infested with pocket gophers = Davis Lake, Oregon = before treatment. = a Same area one year later after pocket gophers were brought under control and native grases had had a chance to reseede Farm land infestation - Texas. Mounds represent pocket gopher workings. Mountain meadow in Utah. Picture: taken just after snow had melted in spring. Ridges of dirt show extent of pocket gopher operations under snow in winter. | Break in terrace caused by pocket gophers burrowing through embaniment. el7ao Pocket gopher infesta- tion along highway. Flood water starting through a pocket gopher burrow passed under a cememt highway, - Flooded the barrow pit on the opposite side of road, and poured into farmer's field, leaving 2 deep wash as & monument e Damage starting from pocket gopher hole in irrigation canal bank = Soon results in bad breaks causing expensive repairs and loss to crops through failure of irrigation water. : And is often responsible for start of gullies. KANGAROO RATS ° Kangaroo rats abound on millions of acres of desert and semidesert range and farm lands. On ranges that have been over- grazed, kangaroo rats must be controlled before reseeding can be accomplished, as they gather and store practically all of the seed within a radius of 100 yards from their burrows. Close-up of typical kengaroo rat dene ~20= Showing plot protected from both livestock and kangaroo ratse Area on left of fence subject to grazing by both livestock and kengaroo ratse On right of fence shows protectiom from both live- stock and rodents. OT Plot showing grazing by kangaroo rats - livestock being excluded. Open range - note lack of native gZrASseSe Kangaroo rat den around mesquite hush. Note lack of vegetation. Typical kangaroo rat infestatione Trail leading from kangaroo rat den to feeding ground. Close-up of feeding ground. Note rat pellets and close cropped grasse BCP Kangaroo rat den before excavating. Cross section of den, show- ing storage chambers and stored grass seeds. =Z5> Seed heads taken from one kangaroo rat den - A - Burrow grass seed. B = Indian wheat heads, C - Weed seeds. D - Unidentified grass heads. Kangaroo rat den before treatment (July 1, 1935), Papego Indian Reservation, Sells, Arizona. Same location as above two months later after eliminating the kangaroo rats. ~24= ee RABBITS AND HARES Reforestation is greatly hampered by rabbits in cut-over areas where intermittent fires have killed all seedlings over a period of years. In many areas the snowshoe hare will eat off as many as 40 percent of the seedlings and damage up to 70 percent of them. Rabbit-infested reforestation area - Olympic National Forest, Washington. a2 5ea Damage to jackpine caused by snowshoe hares = Dukes, Michigan. Spruce tree with lateral branches removed by snow= shoe hares = Price County, Wisconsin. @26=@ Healthy Norway pine. Snow- shoe hare damage to pine and spruce seedlings at this stage of growth consists of nipping the terminal bud. Typical damage to cornfield by jack rabbits = Texas. PORCUPINES On many national forest areas the control of porcupines is imperative from the standpoint of timber reproduction. This is especially true on cut-over areas and where fires have destroyed all seedlings. Porcupines will often destroy up to 90 percent of the seedlings and, through continued girdling of young trees 15 to 25 years of age, will destroy all chance for commercial timber for many years to comes Typical porcupine dene Picture taken on Pike National Forest in Colorado, in area where porcupine control work was conducted under the Forest Service E. C. W. programe A i Poreupine at work girdling pine treee Showing one of 114 young pines damaged by porcupines on 15 acrese Additional evidence on cut-over arease =a2Sa= OO ee Complete girdling by porcupines about 12 inches above ground. Porcupine at foot of tree probably 15 years old, which it has damaged beyond hope of recoverye A TYPICAL E. C. We CREW Ee C. We. crews have treated almost 12,000,000 acres of rodent=-infested lands during the past three years, have done it carefully and well, and in so doing have been taught valuable lessons in wildlife management. ZO.