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UNITED STATES DEPARTMENT OF AGRICULTURE

FARMERS' BULLETIN

WASHINGTON, D. C. 702 JANUARY 17, 1916

Contribution from the Bureau of Biological Survey, Henry W. Henshaw,
Chief.

COTTONTAIL RABBITS IN RELATION TO TREES AND FARM CROPS.

By D. E. LANTZ, _Assistant Biologist_.

[Transcriber's Note: Words surrounded by tildes, like ~this~ signifies
words in bold. Words surrounded by underscores, like _this_, signifies
words in italics.]




CONTENTS.


                                   Page.

Introduction                           1

Habits of cottontail rabbits           2

Protection of rabbits                  3

Means of repressing rabbits            5
    Natural enemies                    5
    Hunting                            6
    Trapping                           6
    Poisoning                          9
    Bacterial diseases                10

Protection of crops from rabbits      10
    Rabbit-proof fences               10

Tree protection                       10
    Washes                            10
    Mechanical contrivances           11
    Other means                       12


NOTE.--This bulletin discusses the distribution and habits of cottontail
rabbits and methods of controlling their ravages on trees and cultivated
crops by means of trapping, poisoning, and supplying safeguards. For
general distribution.




INTRODUCTION.


Among the serious pests in orchards and tree plantations are the several
native species of rabbits. These animals do considerable damage to
garden truck and other farm crops also, especially on lands recently
opened to cultivation. North American rabbits belong to two general
classes easily distinguished by their size and habits.

The larger forms[1] include the arctic and varying hares, or snowshoe
rabbits, and the jack rabbits, and are found throughout nearly all of
Alaska and Canada and in all the States west of the Mississippi except
Arkansas and Louisiana. East of the Mississippi they inhabit the
northern parts of Minnesota, Wisconsin, and Michigan, most of New York
and New England, and southward in the Appalachian Mountains, parts of
Pennsylvania, Maryland, and Virginia.

[Footnote 1: Genus _Lepus_.]

The smaller forms,[2] generally called "cottontail rabbits," occur in
every State, but are absent from the greater part of Maine, the
northern parts of New Hampshire, Vermont, New York, Michigan, Wisconsin,
and Minnesota, and from the western parts of Washington and Oregon. In
recent years they have extended their range northward in the New England
States, New York, and portions of the West, and have invaded and
occupied a considerable part of the Province of Ontario. In habits they
differ materially from the larger rabbits. They live in copses and
thickets more than in open fields. The young are born blind, naked, and
helpless, while those of the larger rabbits have the eyes open, are
partially furred, and active when born.

[Footnote 2: Genus _Sylvilagus_.]

Rabbits of both genera, however, feed exclusively on vegetation, and are
at times harmful to crops and especially to trees. Because of their size
and great abundance in parts of their range, jack rabbits are by far the
most destructive, but, except in a few places where they have been
introduced, none are found east of the Mississippi. Epizootics (diseases
which attack many animals at the same time) are an effectual natural
check, and after such attack occurs, jack rabbits are usually so reduced
in numbers that they are not troublesome again for several years.

Traps and other devices that are effective with cottontail rabbits do
not always succeed with jack rabbits. The recommendations contained in
this bulletin will, therefore, apply only to cottontail rabbits, but
they may suggest methods that, with modifications, may be used against
the larger forms.




HABITS OF COTTONTAIL RABBITS.


Cottontail rabbits (fig. 1) are so well known that little need be said
of their habits. They breed several times each year during the warmer
months, the litters averaging five or six young. The nest is usually
placed in a hollow or depression of the ground, often in open fields or
meadows. It is composed of dead grass and warmly lined with fur which
the female pulls from her own body. The male rabbit takes no part in
caring for the young, and the female weans them as soon as they are able
to leave the nest. These animals breed so rapidly that in spite of many
natural enemies, and of the fact that they are hunted for human food,
they often become numerous enough to inflict serious losses on farmers
and fruit growers in many parts of the United States (fig. 2).

Cottontail rabbits eat all sorts of herbage--leaves, stems, flowers, and
seeds of herbaceous plants and grasses--and leaves, buds, bark, and
fruits of woody plants or trees. They usually prefer the most succulent
foods, as young shoots, tender garden vegetables, clover, alfalfa, and
fallen ripe fruits; but they exhibit also a remarkable delicacy of
taste in their selection of certain varieties of cultivated plants and
in their neglect of others of the same species. Prof. C. V. Piper
reports that in Oregon rabbits ate Arabian alfalfa down to the ground,
while they did little or no damage to other varieties grown in
surrounding plats. Prof. C. A. Mooers, of the Tennessee Agricultural
Experiment Station, reports similar observations in regard to their
taste for soy beans, stating that they greatly relish the mammoth yellow
variety and that it is practically the only one that suffers from their
depredations. When favorite foods are absent rabbits resort to whatever
is available. It is during summer droughts or when deep snows cut off
ordinary supplies that the animals attack the bark of growing trees or
shrubs.

[Illustration Fig. 1.--Cottontail rabbit in its "form."]


PROTECTION OF RABBITS.

Cottontail rabbits are valuable for food and afford excellent sport for
gunners. In many States, especially east of the Mississippi River, they
are protected as game. In fruit-growing and truck-farming districts
farmers regard them with disfavor, and there is considerable rivalry
between sportsmen and farmers to have their opposing views reflected in
game laws. The interests of the two classes do not seriously differ,
however, for when rabbits are closely hunted losses from their
depredations are usually reduced to a minimum. Still there is danger
that in years favorable for their increase the animals may inflict
serious injury to trees during severe winters.

Rabbits are protected (1915) by close seasons in States and Provinces as
shown in Table I. Twenty-eight States, Alaska, and the Canadian
Provinces not mentioned in the table do not protect rabbits of any kind.
In the District of Columbia all shooting is prohibited except on certain
river marshes. In Kentucky rabbits may be taken with dog, trap, or snare
at any time, and the close season for shooting is evidently solely for
the purpose of keeping gunners out of fields and woods during the two
months immediately preceding the open season for quails. In Wisconsin 46
counties, mostly in the southern half of the State, have no close season
for rabbits. In California only cottontails, or bush rabbits, are
protected.

[Illustration Fig. 2.--Apple tree killed by rabbits.]

TABLE I.--_Lengths of open season for rabbits or hares._

----------------------+-----------+-----------+---------
                      | Beginning | Beginning | Length
State or Province.    | of        | of        | of open
                      | open      | close     | season.
                      | season.   | season.   |
----------------------+-----------+-----------+---------
                      |           |           | _Months._
Maine                 | Oct. 1    | Apr. 1    |  6
New Hampshire         | do.       | Mar. 1    |  5
Vermont               | Sept. 15  | do.       |  5-1/2
Massachusetts         | Oct. 12   | do.       |  4-3/5
Rhode Island          | Nov. 1    | Jan. 1    |  2
Connecticut           | Oct. 8    | do.       |  2-3/4
New York              | Oct. 1    | Feb. 1    |  4
  Long Island         | Nov. 1    | Jan. 1    |  2
New Jersey            | Nov. 10   | Dec. 16   |  1-1/5
Pennsylvania          | Nov. 1    | Dec. 1    |  1
Delaware              | Nov. 15   | Jan. 1    |  1-1/2
Maryland              | Nov. 10   | Dec. 25   |  1-1/2
District of Columbia  | Nov. 1    | Feb. 1    |  3
Virginia              | do.       | do.       |  3
Kentucky              | Nov. 15   | Sept. 15  | 10
Ohio                  | do.       | Dec. 5    |  2/3
Indiana               | Apr. 1    | Jan. 10   |  9-1/3
Illinois              | Aug. 31   | Feb. 1    |  5-1/30
Michigan              | Oct. 1    | Mar. 2    |  5-1/30
Wisconsin:            |           |           |
  6 counties          | Sept. 10  | Feb. 1    |  4-2/3
  13 counties         | Oct. 10   | do.       |  3-2/3
  6 counties          | Nov. 1    | Jan. 1    |  2
Colorado              | Oct. 1    | Mar. 1    |  5
California            | July 31   | Feb. 1    |  6-1/30
British Columbia      | Sept. 1   | Jan. 1    |  4
Ontario               | Oct. 1    | Dec. 16   |  2-1/2
Quebec:               |           |           |
  Zone 1              | Oct. 15   | Feb. 1    |  3-1/2
  Zone 2              | do.       | Mar. 1    |  4-1/2
Newfoundland          | Sept. 20  | Jan. 1    |  3-1/3
Prince Edward Island  | Nov. 1    | Feb. 1    |  3
Nova Scotia           | Oct. 1    | Mar. 1    |  5
----------------------+-----------+-----------+---------

In about half the States that have a close season for rabbits the laws
permit farmers and fruit growers to destroy the animals to protect crops
or trees. Such provision might well be incorporated in game laws of all
States. For lack of it farmers have sometimes suffered severe losses,
and not a few have been compelled to pay fines for trying to protect
their property from rabbits. In States that protect rabbits it is well
for the farmer to be acquainted with the game laws and in case of doubt
to have a clear understanding with local and State game, wardens before
undertaking to destroy rabbits.




MEANS OF REPRESSING RABBITS.


NATURAL ENEMIES.

Among the agencies that help to keep down the numbers of rabbits few are
more effective than carnivorous birds and mammals. These include large
hawks and owls, eagles, coyotes, wildcats, foxes, minks, weasels, dogs,
and cats. Eagles, the larger species of hawks, and all the large and
medium-sized owls make rabbits a great part of their food. From the
standpoint of the farmer and fruit grower these birds and certain
carnivorous mammals are far more beneficial than harmful. On the other
hand, poultry growers and sportsmen regard them as enemies to be
destroyed whenever possible. In the absence of such natural enemies,
rabbits, as well as rats and mice, often become a menace to valuable
crops. Indiscriminate slaughter of carnivorous birds and mammals should
be suppressed whenever rodent pests are to be controlled.


HUNTING.

Hunting has been the most important factor in keeping down the numbers
of rabbits in America. In some parts of the country the animals have
been so reduced in numbers by shooting that sportsmen have invoked
legislation to prevent their extermination. Shooting is undoubtedly the
best method for hunting this animal. Ferreting is often impracticable,
since our native rabbits do not habitually burrow; besides, the use of
ferrets is forbidden by law in many States that protect the rabbit.
Coursing with greyhounds is popular in the West, where the swifter jack
rabbits are abundant. Cottontails are often chased with foxhounds, but
the beagle is rapidly taking precedence as a favorite for hunting these
animals, the gun being used to secure the game.

Where the country is sufficiently open for the purpose, the organized
hunt, in which everyone who owns a gun is supposed to take part, is a
good means of reducing the number of rabbits. These organized hunts are
popular in the West, where they are also varied, in the case of jack
rabbits, by what is known as the "rabbit drive." A large territory is
surrounded by men and the animals are driven into a corral built of wire
netting. While a few cottontails are sometimes included in the catch,
these usually find refuge in open burrows or under cover of rocks or
brush, so that this method is hardly applicable to them.


TRAPPING.

Rabbits are easily trapped or snared, and while these methods of taking
them are slow, they are always feasible when cottontails infest woodlot,
orchard, nursery, field, or garden. Many are caught in old-fashioned box
traps set with a figure-4 trigger with cord attached to hold up the box
lid.

An improvement on this familiar trap, widely used in the Middle West,
and often called the Wellhouse[3] trap, is a box 21 inches long and
about 6 inches high and 4 inches wide (inside measurements) made of
6-inch fence boards, preferably old ones. The box is closed at the rear
and has a wire door in front which swings inward from the top, a cleat
at the bottom preventing its opening outward. The trap is set and the
wire door kept open by a wire trigger-rod held in place by two staples
in the top of the box. The trigger-rod is bent downward into a loop or
figure 8 near the rear of the trap. As the rabbit enters the trap and
crowds into the back part it presses against the loop, moves the
trigger-rod backward and is imprisoned as the wire door is released and
falls. Bait may be used but is unnecessary, since cottontails frequently
take refuge in dark places from enemies or inclement weather.

[Footnote 3: After the late Mr. Fred Wellhouse, of Topeka, Kans.]

[Illustration: FIG. 3.--Details of a Wellhouse rabbit trap.]

The materials needed for making a Wellhouse trap are: Four boards 1 by
6, 21 inches long, for the sides; a piece 1 by 6, 8 inches long, for the
back; a small cleat for the door stop; 28-1/2 inches of wire for the
door; 22 inches of wire for the trigger; 4 small staples for hanging the
door and trigger; and nails (fig. 3).

[Illustration: FIG. 4.--Cross section of a Walmsley tile trap for
rabbits.]

Mr. J. M. Walmsley recently sent to the department photographs and a
description of a permanent rabbit trap made of sewer tile and used on
his and other farms in Kansas (fig. 4). A 12 by 6 inch "tee" is set with
the long end downward and buried so that the 6-inch opening is below the
surface of the ground. Two lengths of 6-inch sewer pipe are then
connected horizontally with the opening. Soil is placed over the joints
to exclude light. The upright tile should be fitted with a tight
removable cover--Mr. Walmsley uses old harrow disks for the purpose. The
projecting end of the small tile is surrounded with rocks, brush, or
wood, so as to make the hole look inviting to rabbits (fig. 5), and that
they may appropriate the den as a place of concealment and shelter. A
number of these traps in various places, and especially in the vicinity
of the orchard, have kept Mr. Walmsley's farm comparatively free of
rabbits. Rabbits occupy these tile traps, go in or out at will, and may
be captured when desired. Whenever Mr. Walmsley visits his traps he is
accompanied by a trained dog that locates the trapped animals. The cover
is lifted from the upright tile and the rabbit captured by hand; if it
bolts from the side opening it is caught by the dog. A short pole fitted
with a 5-inch wooden disk may be inserted in the side opening to prevent
escape.

[Illustration: FIG. 5.--A Walmsley tile trap in use.]

These traps are especially suitable for open lands and prairies, where
rabbits can not find many natural hiding places. Built on waste land,
they may become a permanent part of the farm equipment and will cost
nothing for repairs from year to year. Their first cost may be greatly
reduced by use of second-grade or even broken tiles. If one wishes to
poison rabbits, the baits may be placed inside these traps and domestic
animals or birds will not be endangered. The Walmsley trap also
furnishes an excellent means of obtaining rabbits for the table or even
for market without damaging them by shooting.


POISONING.

Poison for killing rabbits has been used in the West with considerable
success. Only in exceptional cases, however, is its use advisable in
States that protect rabbits. The most favorable season for using poison
is in winter or after a long drought in summer has made green food
scarce. In some localities summer poisoning is interfered with by
crickets or grasshoppers consuming the bait.

The following method is adapted for general use: Insert crystals of
strychnine or powdered strychnine in pieces of apple or melon rind and
place these baits at intervals along rabbit runs or paths. ~Take care to
put the poisoned baits where children and domestic animals can not get
them.~ Where no well-defined runs are visible in orchards, artificial
ones may be made with a narrow drag or scraper. Along such runs or the
dead furrows of plowed fields rabbits habitually travel. Baits may be
placed on the ground or elevated on short sticks along the path, and
should be looked after with care. ~Any baits left after poisoning
operations are finished should be destroyed.~

For poisoning rabbits in winter or during droughts the following formula
is recommended: Good oats, 12 quarts; powdered strychnine, 1 ounce;
laundry starch, 1 tablespoonful; soda (bicarbonate), 1 ounce;
saccharine, 1/8 ounce; water, 1 quart. Mix the starch with 1/2 pint of
cold water. Pour this into 1-1/2 pints of boiling water and continue the
boiling for a minute or two until the starch is clear. Mix the dry
strychnine and soda in a small pan and sift it over the hot starch,
stirring thoroughly to form a smooth paste. Add the saccharine and stir
again. Pour the mixture over the oats in a metal tub, mixing until all
the grain is wet. Allow the oats to dry before distributing. Not over a
tablespoonful of the grain should be put in a single bait and this
should be scattered considerably. A little alfalfa hay will help attract
rabbits to the poisoned grain. This poison is recommended for use when
snow covers the ground. It is effective against both cottontails and
large rabbits.

Partly ripened heads of barley or wheat soaked in a solution of
strychnine and saccharine or coated with the starch-strychnine solution
just described have also proved effective baits for rabbits, but ~great
care must be exercised~ in using them, as ~they are likely to be eaten by
live stock~.

Cottontail rabbits may be poisoned in winter by baiting them with twigs
cut from apple trees and dipped in or thinly coated with the
starch-strychnine poison. These twigs are scattered along rabbit trails
and are effective against both meadow mice and rabbits. They are less
dangerous to domestic animals than grain baits.


BACTERIAL DISEASES.

The fact that when rabbits become excessively abundant in any locality
epizootic diseases often destroy them in large numbers has led many
people to expect that a micro-organism would be found which would afford
a ready means of rabbit control. The Biological Survey receives many
applications for such bacterial preparations. In reply to all of them it
has been necessary to state that thus far all attempts to spread
contagious disease artificially among wild rabbits have failed to give
practical results.




PROTECTION OF CROPS FROM RABBITS.


Complete extermination of rabbits in any part of the United States is
not desirable, even if possible. They should be reduced in numbers only
sufficiently to secure comparative safety to crops, and before active
wholesale destruction of the animals is attempted the possibility of
crop protection by other means should be carefully considered. In many
cases one of these means would probably be the more economical method.


RABBIT-PROOF FENCES.

When rabbits are abundant and the area to be protected is not too great,
a rabbit-proof fence may profitably be used. Woven-wire netting is
recommended for this purpose. This material is in general use, not only
against the rabbit pests of Australia and Europe, but in our own country
against both large and small rabbits. As our species burrow less than
the European rabbit the requirements for rabbit proofing a fence here
are not so great. Even the cottontails, when driven by hunger, will dig
under a fence, but this may be prevented either by use of wire with
close barbs in contact with the ground or by plowing a furrow against
the lower edge. A netting of galvanized wire with 1-1/2-inch mesh and
2-1/2 to 3 feet high is a sufficient barrier against cottontails. Where
snow is infrequent market gardeners and nurserymen use a 2-foot fence,
but in the North they prefer to use a netting 3-1/2 feet wide, and to
turn from 4 to 6 inches of the lower edge flat and cover it with soil.
Netting made of No. 20 wire costs from 25 to 35 cents a rod. Heavier
netting slightly increases the cost, but adds to the durability of the
fence. Where lumber is cheap, a picket fence or one made of laths and
wire is practicable. When deep snows fall and drifts form, fences offer
no protection to crops against rabbits.




TREE PROTECTION.


WASHES.

Many devices for protecting trees from rabbits have been recommended,
the majority of which are paints, smears, or washes supposed to be
distasteful to the animals. Many are not sufficiently permanent to
afford protection for an entire winter, and most of those that are
lasting are injurious to trees. Coal tar, pine tar, tarred paper, and
oils, under certain conditions, are dangerous to young trees. Carbolic
acid and other volatile substances afford only temporary protection, and
must be renewed too often to warrant their use. Bitter substances, like
commercial aloes and quassia, are useless against rabbits.

The most promising simple washes for protecting large trees from rabbits
are those containing lime mixed with sulphur or copperas in various
combinations. Lime alone is not sufficiently permanent, especially where
much rain falls. When mixed with sufficient copperas it has a deep green
color and sticks much better. The lime-sulphur wash commonly used to
destroy San Jose scale in winter has often proved successful as a rabbit
repellent, but its lack of adhesive qualities often makes it fail. The
defects may be partly corrected by mixing salt, soap, or a cheap glue
with the lime and sulphur while the wash is still hot.

A poisoned wash of starch and glycerin, tried during the winter of
1913-14 in Idaho by a field agent of the Biological Survey, gave
excellent results in protecting young orchards from jack rabbits, and
would probably be equally effective where cottontails are concerned. The
wash is prepared as follows:

Dissolve 1 ounce of strychnine (sulphate) in 3 quarts of boiling water.
Dissolve 1/2 pound of laundry starch in 1 pint of cold water. Pour the
starch into the vessel containing the strychnine and boil the mixture a
short time until it is clear, adding 6 ounces of glycerin and stirring
thoroughly. When it is cool enough apply with a paint brush to the tree
trunks.

The glycerin and starch adhere well and form a thin coating to the bark.
Rabbits attacking the trees will be quickly killed. In the Idaho
experiments none of the trees were damaged badly enough to affect their
growth and all the rabbits in the orchards were destroyed. The method is
well worth trying; but ~care should be taken not to endanger domestic
animals~.


MECHANICAL CONTRIVANCES.

Among the best mechanical contrivances for protecting trees from rabbits
are cylinders of woven wire netting. Poultry netting of 1-inch mesh,
made of No. 20 galvanized wire, will answer every requirement. Rolls 18
inches wide are used for cottontails, and the material is cut into
1-foot lengths. One of the sections is rolled into cylindrical shape
about the trunk of each tree and fastened at several places by bending
and twisting the projecting ends of wire. No other fastening is needed,
but stakes or spreaders may be used to prevent rabbits from pressing the
wire against the bark and doing injury through the meshes. These guards
should be left on the trunks, and will last as long as the trees require
protection. The cost of material is less than 2 cents for each tree.
These protectors may vary in size to suit the requirements of any
particular locality or kind of tree. They may be adapted to protection
from the larger rabbits by using wider rolls and to protection from both
meadow mice and rabbits by using wire of finer mesh and by pressing the
lower edges into the ground.

Veneer and other forms of wooden protectors are popular, and have
several advantages when used for cottontail rabbits. When left
permanently upon the trees, however, they furnish retreats for insect
pests. For this reason they should be removed each spring. While the
labor of removing and replacing them is considerable, they have the
advantage when pressed well into the soil of protecting from both mice
and rabbits. They cost from 60 cents a hundred upward, and are much
superior to building paper or newspaper wrappings. The writer has known
instances where rabbits tore wrappings of building paper from apple
trees and in a single night injured hundreds. "Gunny-sack" and other
cloth wrappings well tied on are effective protectors. Cornstalks
furnish a cheap material for orchard protection when cut into lengths of
18 to 20 inches, split, and tied with the flat side against the tree, so
as fully to cover the trunk. However, they last but one season and
putting them in place involves much labor.


OTHER MEANS.

Few of these methods for the protection of individual trees in orchards
or elsewhere are applicable to young woodlands or forest plantations
where trees grow close together. In these cases the only remedy is the
destruction of the animals or their exclusion by wire nettings.

Clean cultivation, generally, possesses advantages in preventing rabbit
depredations, since it reduces the number of places of refuge for the
animals; but rabbits go long distances in search of food, especially in
winter, and clean cultivation can not be applied on the western plains,
where dense windbreaks are essential to successful orcharding.

Feeding rabbits in winter to prevent their attacks on orchards has been
practiced successfully, on the theory that it is cheaper to feed than to
fight them. One plan is to leave the winter prunings of apple trees
scattered about the orchard. Another is to furnish corn, cabbage, or
turnips in sufficient quantity to provide food for the rabbits during
cold weather. These methods have considerable merit, particularly the
first, which seems to give satisfactory results when both mice and
rabbits are present.

WASHINGTON: GOVERNMENT PRINTING OFFICE: 1916