Produced by Tom Cosmas from materials provided by The Internet Archive.








  +----------------------------------------------------------------------+
  |            United States Department of Agriculture                   |
  |                  Bureau of Biological Survey                         |
  |                           -------                                    |
  |           Wildlife Research and Management Leaflet BS-54             |
  +----------------------------------------------------------------------+
  |  Washington, D. C.                              Rev., December 1936  |
  +----------------------------------------------------------------------+


          RODENT CONTROL AIDED BY EMERGENCY CONSERVATION WORK


        By Stanley P. Young, Chief, Division of Game Management




Contents

                                                   Page

  Need for rodent control                            1
  Federal, State, and local cooperation              2
  Training of E.C.W. crews                           2
  Timeliness of emergency aid                        3
  Forest and forage protection                       3
  Aid in erosion control                             4
  Examples of benefits derived                       4
  Safeguarding harmless species                      5
  Control work illustrated                           6
    Prairie dogs                                     7
    Ground squirrels                                13
    Pocket gophers                                  15
    Kangaroo rats                                   20
    Rabbits and hares                               25
    Porcupines                                      27
    A typical E.C.W. crew                           30


Need for Rodent Control

The Emergency Conservation Work Program has been of inestimable value
in the control of prairie dogs, ground squirrels, pocket gophers,
kangaroo rats, rabbits, and porcupines. The citizens of the West have
been forced to carry on campaigns 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 as vital
as is the proper spraying of trees throughout the East to prevent
damage by insects. These small mammals cover the western ranges by
countless thousands, and control is necessary if crops are to be grown.

Rodent control is nothing new. Records indicate that as early as 1808,
strychnine was shipped by boat around Cape Horn to the Santa Barbara
Mission, Calif., in order that the early settlers might kill off the
ground squirrels. A constant fight has been waged ever, since, but
unfortunately, while the landowners were willing to finance the killing
of squirrels on 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 holdings.


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 of 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 the three fiscal
years 1934 to 1936 a total of almost 20,000,000 acres had been covered
by E.C.W. for the control of these various rodent pests. On the statute
books of several Western States rodent-control laws provide that
landowners may establish rodent-control districts wherein all lands
are treated simultaneously 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 adjacent to private 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
expended $665,785 for the purpose, while the Biological Survey was able
to expend only $226,623 from regular appropriations. The E.C.W. 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.


Training of E.C.W. Crews

Rodent control is one of the most popular projects with E.C.W.
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 liked to work in these crews, as
it afforded them opportunity to become 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 and
harmless species, the Biological Survey has insisted upon approving the
appointments of all men employed on the supervision of rodent-control
work for its various cooperating agencies. This is for the reason that
when poisoning campaigns are properly handled and carefully supervised,
there is little danger of the accidental poisoning of other animals.
The records indicate that there have been practically no cases of
destruction 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 handling the crews they have imparted knowledge to the
beys that will be of permanent 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 E.C.W. camps were shown films depicting the work
of beavers, showing measures for the protection of elk, deer, and
other big-game animals, and portraying the need of sane, sensible
conservation methods, in order that the remnants of our fast-vanishing
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 Biological 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 to 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.W. program came at the most opportune time. The
extreme drought throughout the west 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 beginning of sheet erosion in
areas where there would still be ample forage for livestock had it not
been 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 carried on a losing fight against drought and rodents. It has
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
kernels 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
foreman with four or five E.C.W. Indians to go from farm to farm and
conduct rodent-control 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
Northwest. 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 survive. Much of
this work would never have been possible but for E.C.W. help.

In the open area, jack rabbits have become a serious pest. The
Biological Survey, in 1934, received a petition bearing the signatures
of more than 8,000 individuals of eastern Colorado, requesting
Government aid in killing jack rabbits, which were ravaging the meager
stocks of forage left after drought and wind had taken their toll.

The Forest Service recognized that rodent control would be essential
if the Plains Shelterbelt program of planting trees from the Canadian
border to Texas was to be effective, and in 1935 approximately
one-tenth of its entire appropriation for the program was expended for
rodent control under the supervision of the 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 standpoint 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. Wholly dependent upon the herbaceous plants for
  their food supply, their tremendous numbers, 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 rodent-infested areas
  are likely to start cutting, which may develop into destructive gully
  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
reclamation projects in the western third of the United States.
Rodents, particularly pocket gophers, find the banks 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.W. 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.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.W. rodent-control program. A group of farmers
living at Springfield, Idaho, suggested to the camp superintendent
there that the jack rabbit control work done by the E.C.W. crew during
the summer of 1935 might pay the cost of the camp. It is estimated that
not less than 600,000 rabbits were killed by this crew on public lands
adjacent to farming areas between American Falls and Moreland, Idaho.
The work afforded protection to not less than half a million dollars
worth of cultivated crops and to more than 75,000 acres of grazing
lands.

The control work carried on by an E.C.W. crew near Weber Lake, Calif.,
in 1933 has been responsible for a 50 percent comeback of the grass
on a large mountain meadow, which had been made a dust heap because
of pocket gopher workings. The pocket gophers had honeycombed the
surface of the ground, and sheep had trampled out most of the grass,
while livestock grazing had been reduced to a negligible figure. The
restoration in two years was due primarily to the elimination of the
pocket gophers.

To control prairie dogs in Oklahoma, an area, of 47,000 acres in
Pawnee, Noble, and Kay Counties was treated through the medium of the
E.C.W. The 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 insufficient Federal funds to treat the Indian lands
until the E.C.W. project afforded opportunity to carry on a systematic
campaign over the entire area. A good piece of work was accomplished,
and this, in conjunction with water developments, made the grass so
much better over these old prairie dog towns in the spring of 1935 that
the Indian Service officials at Pawnee received an increased rental of
25 cents an acre on their grazing lands. On areas where they received
50 cents an acre in 1934, they received 75 cents in 1935, a direct
increase in receipts to the Federal Treasury.

The permanent benefit accruing to the Indians from E.C.W. rodent
control is summed up as follows by an Agricultural Extension agent of
the Indian Service, at Anadarko, Oklahoma:

  "No little stress can be placed upon the financial value of the
  rodent-control project to the Indians. The Indian enrollees received
  the labor benefit on both Indian 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 heavy prairie dog infestation of the allotted land
  it had become necessary to reduce the rental value of the grass land
  infested. Now that the prairie dogs have been controlled the rental
  value will be increased by approximately 10 cents or more per acre
  because the pastures will regrass and the carrying capacity will be
  increased. In comparing this increase in rental value with the cost
  of controlling the prairie dogs, the Indians will reap the financial
  benefit of the Government expenditures in two or three years.
  Therefore, this project has certainly been of utmost value to the
  reservation and the Extension Division in helping the Indian to help
  himself."


Safeguarding Harmless Species

Some persons uninformed as to the need for rodent control and the
methods followed by the Biological Survey in carrying on the work have
stated that control by use of poison and C.C.C. workers endangers the
existence of other forms of wildlife. This, however, is not the case.
The Biological 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. Scientific investigations conducted
by the Bureau are bringing increasing knowledge of the habits of
economically injurious species and of their physiological reaction to
various baits. This has made it possible to use more and more specific
control methods and so to select, prepare, and expose poison baits as
not seriously to endanger animals other than those for which the baits
are intended. When these scientific methods are carried out under
direct supervision of trained personnel, the total number of beneficial
species destroyed is negligible.

The Biological Survey is a conservation organization and will undertake
no work that will be detrimental to any species of animal not
interfering too greatly with the interests of man. Those conversant
with actual conditions in the range States realize that if agriculture
is to survive, the control of injurious rodents is as essential as
is control of the corn borer, the chinch bug, the boll weevil, the
grasshopper, the coddling moth, and numerous other agricultural
pests. The Survey insists that in conducting work of this sort, the
most careful supervision by trained technicians must be given. All
cooperating agencies recognize the necessity for such supervision, and
as a result a most worth-while program has been carried on during the
past three fiscal years. The Biological Survey has entered into written
cooperative understandings with the various governmental agencies under
which rodent-control activities have been conducted. These agreements
place the responsibility for technically supervising all rodent-control
activities in the hands 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, the story of rodent damage 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.

[Illustration]

Prairie dog mounds on abandoned Indian farm, Southern Navajo
Reservation, Arizona.

[Illustration]

Area practically denuded of grass by prairie dog--Wescalero Indian
Reservation, New Mexico.

[Illustration]

Dogs on leash and tin cans rattling in the wind are some of the
primitive methods employed by Indians in futile attempt to save crops
from ravages of prairie dogs in the Southwest.

[Illustration]

[Illustration]

Indian cornfield totally destroyed by prairie dogs.

[Illustration]

Cotton and corn fields damaged by prairie dogs in northwest Texas.

[Illustration]

[Illustration]

Side of basin denuded by prairie dogs--devastation being rapidly
completed by erosion. Cochetopa Forest, Colorado.

[Illustration]

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 11.

[Illustration]

[Illustration]

Overgrazing, wind, and flood--

[Illustration]

resulting in gullies and arroyos.

[Illustration]

[Illustration: 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 farm.]

GROUND SQUIRRELS

[Illustration: Ground squirrel damage. Semidesert type country. Note
squirrel at mouth of burrow.]

[Illustration: E.C.W. ground squirrel control crew--Payette National
Forest, Idaho.]

[Illustration: E.C.W. crew at work on Umatilla National Forest,
Washington.]

[Illustration]

Ground squirrel burrows become waterways during a rain and are the
beginning of this type of erosion.

[Illustration]

Papago Indian Reservation, Arizona.

POCKET GOPHERS

[Illustration: Typical mountain range land, heavily infested with
pocket gophers--Davis Lake, Oregon--before treatment.]

[Illustration: Same area one year later after pocket gophers were
brought under control and native grasses had had a chance to reseed.]

[Illustration: Farm land infestation--Texas. Mounds represent pocket
gopher workings.]

[Illustration: 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.]

[Illustration: Pocket gopher infestation--Louisiana.]

[Illustration: Break in terrace caused by pocket gophers burrowing
through embankment.]

[Illustration: Pocket gopher infestation along highway.]

[Illustration: Flood water starting through a pocket gopher burrow
passed under a cement highway,--]

[Illustration: Flooded the barrow pit on the opposite side of road, and
poured into farmer's field, leaving a deep wash as a monument.]

[Illustration: Damage starting from pocket gopher hole in irrigation
canal bank--]


[Illustration: Soon results in bad breaks causing expensive repairs and
loss to crops through failure of irrigation water.--]

[Illustration: 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 overgrazed, 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.

[Illustration: Close-up of typical kangaroo rat den.]

[Illustration: Showing plot protected from both livestock and kangaroo
rats.]

[Illustration: Plot showing grazing by kangaroo rats--livestock being
excluded.]

[Illustration: Area on left of fence subject to grazing by both
livestock and kangaroo rats. On right of fence shows protection from
both livestock and rodents.]

[Illustration: Open range--note lack of native grasses.]

[Illustration: Kangaroo rat den around mesquite bush. Note lack of
vegetation.]

[Illustration: Typical kangaroo rat infestation.]

[Illustration: Trail leading from kangaroo rat den to feeding ground.]

[Illustration: Close-up of feeding ground. Note rat pellets and close
cropped grass.]

[Illustration: Kangaroo rat den before excavating,]

[Illustration: Cross section of den, showing storage chambers and
stored grass seeds.]

[Illustration: Seed heads taken from one kangaroo rat den--

  A--Burrow grass seed.
  B--Indian wheat heads.
  C--Weed seeds.
  D--Unidentified grass heads.]

[Illustration: Kangaroo rat den before treatment (July 1, 1935), Papago
Indian Reservation, Sells, Arizona.]

[Illustration: Same location as above two months later after
eliminating the kangaroo rats.]

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.

[Illustration: Rabbit-infested reforestation area--Olympic National
Forest, Washington.]

[Illustration: Damage to jackpine caused by snowshoe hares--Dukes,
Michigan.]

[Illustration: Healthy Norway pine. Snowshoe hare damage to pine and
spruce seedlings at this stage of growth consists of nipping the
terminal bud.]

[Illustration: Spruce tree with lateral branches removed by snowshoe
hares--Price County, Wisconsin.]

[Illustration: 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 come.

[Illustration: Typical porcupine den. Picture taken on Pike National
Forest in Colorado, in area where porcupine control work was conducted
under the Forest Service E.C.W. program.]

[Illustration: Porcupine at work girdling pine tree.]

[Illustration: Showing one of 114 young pines damaged by porcupines on
15 acres.]

[Illustration: Additional evidence on cut-over areas.]

[Illustration: Porcupine at foot of tree probably 15 years old, which
it has damaged beyond hope of recovery.]

[Illustration: Complete girdling by porcupines about 12 inches above
ground.]

A TYPICAL E.C.W. CREW

[Illustration: E.C.W. 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.]


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Transcriber's Note


Original publication appears to have been a copy of a typewritten
document.