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United States Department of Agriculture
Bureau. of Biological Survey

Washington, D. C. - May 1936

RODENT CONTROL AIDED BY EMERGENCY CONSERVATION WORK

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

The Emergency Conservation Work Program has been of inestimable
value in the control of prairie dogs, ground squirrels, pocket gophers,
kangaroo rats, rabbits, and other native rodent pests. 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. The control of
rodents is as vital to the agricultural interests of the West as is the proper
spraying of trees to prevent damage by insects throughout the East. 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 land-
owners were willing to finance killing the squirrels on their owm 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.

When the Emergency Conservation 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 finances permitted. During the
three years, 1933 to 1935, a total of almost twelve million acres have been
covered by ECW for the control of these various rodent pests. Rodent-control
laws on the statute books of several Western States 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 be-
fore the ECW program were there adequate Federal funds to make these laws
effective by taking care of the infested public lands adjacent to private
holdings.

Rodent control is one of thé most popular projects with ECW 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 rodent control but with the various habits of
wildlife as well.

; ia onderce emoilon proper methods and place all possible safeguards:
around poisoning operations for the protection of beneficial and harmless
species, the Biological Survey has insisted upon handling the supervision
of all rodent-control work for its various cooperating agencies. 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 ECW rodent-control program. Naturally, the
supervisors not only must know rodent cmtrol but also be acquainted with
the habits and status of wildlife in general, and in handling the crews
they have imparted knowledge to the boys that will be of aaa benefit
to them and to the Nation.

Educational programs were provided as regularly as possible, in order
to tell the CCC enrollees of various wildlife problems. The entire personnel
of ECW camps were showmm 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 wildlife might be preserved. Mimeographed
leaflets on wildlife management studies were made up by district.agents of
the Survey for distribution to the boys in order that they might be given
as broad instruction 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, 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.

Fortunately, the ECW program came at the most opportune time. The
extreme drought throughout the West had forced rodents from the open lands
into the 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 al-
most entirely denuded the surface soil of its vegetation. This has caused
sheet erosion to ‘start 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 1935, there had been three years
of drought, and this, coupled with rodent damage, had reduced corn production

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to the point where they had barely: enough for the spring seeding. All the
Indians were clamoring for aid, and in order to save their last crop of corn
it was necessary to detail a Boron with four or five ECW Indians to go from
farm to farm and conduct rodent-control operations.

The Forest Service is endeavoring to carry on a reforestation program
throughout much of the cutsover 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, survive,
Much of this work would never have been possible but for ECW,

In the open Meine Pivlameblts have become-a serious pest. -The Biological
Survey, in 1954, received a petition from-eastern Colorado, bearing the signa-—
tures of more than 9,000 individuals, requesting-Government aid in killing
rabbits, which were ravaging the meager stocks of forage left after oreney
and wind had taken their toll. ;

The Forest Servive has realized that rodent control must be one of the
major projects if the Shelterbelt program of planting trees from the Canadian
border in Texas is to be effective, and in 1935 approximately one-tenth of its
entire appropriation for this purpose was expended for rodent control under the
supervision of the Biological Survey. Crews patrol the planted areas constantly
to prevent the gnawing of the seedlings by jack rabbits and pooket gophers.

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 throughout many of the Western States, contributes only about 25 per-
cent of the total cost of rodent-control operations. During the fiscal year
1935, States, counties, and private individuals expended $553,779 for the
purpose, while the Biological Survey was able to expend only $185,973 from
regular appropriations, The ECW program afforded the first opportunity of
somewhere near meeting the Pederal 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 infest and reinfest private holdings.

The permanent benefits accruing from the ECW 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,

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their tremendous numbers have been an important contributing factor along
with over—gnazing by livestock and unfavorable climate in depleting this
cover, and’ thus have greatly reduced the protection afforded tne 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 gulley erosion because of the almost immediate accumula-
tion of run-offs in the myriads of burrows and channels which these
animals construct just under the surface of the soil."

The Soil Conservation Service récognizes the relation of rodents
to the revegetation of the range, and rodent control is one of its prin-—
cipal projects. | :

A few concrete examples will illustrate the great good that has
resulted from the ECW rodent-control program. A group of farmers living
at Springfield, Idaho, suggested to the cemp Superintendent there that the
jack rabbit control work done by tne ECW crew during the summer of 1935
might pay tne 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 graging lands.

The control work carried on by an ECW 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 trempled out most of the grass, while livestock
grazing nad been reduced to a negligible figure. The restoration in two
years time was due primarily to the elimination of the pocket gophers.

To control prairie dogs in Oklahoma, an area of 47,000 acres in
Pawnee, Nobic, and Kay Counties, was trcated through the medium of the
ECW. The Indien lands here are interspersed with private lands, and the
landowners were unable to make any progress in a general clean up. This
was because there were insufficient Federal funds to treat the Indian lands
until the ECW project afforded opportunity to carry on a systematic campaign
over the entire area. A good piece of work was accomplished, and the grass
was So much better over these old prnirie dog towns in the spring of 1955
that the Indien Service officials at Pawnee received an increase 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 Federsl Treasury.

Some persons uninformed as to the need for rodent-control and the
methods followed by the Biologicsl Survey in carrying on the work have
Stated that. control by use of poison and CCC workers endangers the existence
of other forms of wildlife. This, however, is not the case. The Biological
Survey hes. studied rodent-control methods for more than twenty years and in

this period it has developed the most scientific and selective poisons
possible, Occasionally a few seed-eating birds are killed, but the total

number is negligible,

The Biological Survey is a conservation organization and will under-
take no work that will be detrimental to any species of animal not inter-
fering 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 insects that become 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 @ result a most worth—while
program has been carried on during the past three years.

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