Owing to their cunning, it is not always easy to clear rats from
premises by trapping; if food is abundant, it is impossible. A few
adults refuse to enter the most innocent-looking trap. And yet trapping,
if persistently followed, is one of the most effective ways of
destroying the animals.
=Guillotine trap.=--For general use the improved modern traps with a
wire fall released by a baited trigger and driven by a coiled spring
have marked advantages over the old forms, and many of them may be used
at the same time. These traps, sometimes called "guillotine" traps, are
of many designs, but the more simply constructed are preferable.
Probably those made entirely of metal are the best, as they are more
durable. Traps with tin or sheet-metal bases are not recommended.
Guillotine traps of the type shown in figure 5 should be baited with
small pieces of Vienna sausage (Wienerwurst) or fried bacon. A small
section of an ear of corn is an excellent bait if other grain is not
present. The trigger wire should be bent inward to bring the bait into
proper position for the fall to strike the rat in the neck, as shown in
figure 6.
Other excellent baits for rats and mice are oatmeal, toasted cheese,
toasted bread (buttered), fish, fish offal, fresh liver, raw meat, pine
nuts, apples, carrots, and corn, and sunflower, squash, or pumpkin
seeds. Broken fresh eggs are good bait at all seasons, and ripe
tomatoes, green cucumbers, and other fresh vegetables are very tempting
to the animals in winter. When seed, grain, or meal is used with a
guillotine trap, it is put on the trigger plate, or the trigger wire may
be bent outward and the bait placed directly under it.
Oatmeal (rolled oats) is recommended as a bait for guillotine traps made
with wooden base and trigger plate (fig. 7). These traps are especially
convenient to use on ledges or other narrow rat runs or at the openings
of rat burrows. They are often used without bait.
[Illustration: FIG. 6.--Method of baiting guillotine trap.]
A common mistake in trapping for rats and mice is to use only one or two
traps when dozens are needed. For a large establishment hundreds of
traps may be used to advantage, and a dozen is none too many for an
ordinary barn or dwelling infested with rats. House mice are less
suspicious than rats and are much more easily trapped. Small guillotine
traps baited with oatmeal will soon rid an ordinary dwelling of the
smaller pests.
=Cage trap.=--When rats are abundant, the large French wire cage traps
may be used to advantage. They should be made of stiff wire, well
reinforced. Many of those sold in stores are useless, because a
full-grown rat can bend the light wires apart and so escape.
[Illustration: FIG. 7.--Guillotine trap with wooden base and trigger
plate.]
Cage traps may be baited and left open for several nights until the rats
are accustomed to enter them to obtain food. They should then be closed
and freshly baited, when a larger catch may be expected, especially of
young rats (fig. 8). As many as 25, and even more, partly grown rats
have been taken at a time in one of these traps. It is better to cover
the trap than to leave it exposed. A short board should be laid on the
trap and an old cloth or bag or a bunch of hay or straw thrown
carelessly over the top. Often the trap may be placed with the entrance
opposite a rat hole and fitting it so closely that rats can not pass
through without entering the trap. If a single rat is caught it may be
left in the trap as a decoy to others.
Notwithstanding the fact that sometimes a large number of rats may be
taken at a time in cage traps, a few good guillotine traps intelligently
used will prove more effective in the long run.
[Illustration: FIG. 8.--Cage trap with catch of rats.]
=Figure-4 trigger trap.=--The old-fashioned box trap set with a
figure-4 trigger is sometimes useful to secure a wise old rat that
refuses to be enticed into a modern trap. Better still is a simple
deadfall--a flat stone or a heavy plank--supported by a figure-4
trigger. An old rat will go under such a contrivance to feed without
fear.
=Steel trap.=--The ordinary steel trap (No. 0 or 1) may sometimes be
satisfactorily employed to capture a rat. The animal is usually caught
by the foot, and its squealing has a tendency to frighten other rats.
The trap may be set in a shallow pan or box and covered with bran or
oats, care being taken to have the space under the trigger pan free of
grain. This may be done by placing a very little cotton under the
trigger and setting as lightly as possible. In a narrow run or at the
mouth of a burrow a steel trap unbaited and covered with very light
cloth or tissue paper is often effective.
[Illustration: FIG. 9.--Barrel trap: 1, With stiff paper cover; 2, with
hinged barrel cover; _a_, stop; _b_, baits.]
The best bait usually is food of a kind that the rats and mice do not
get in the vicinity. In a meat market, vegetables or grain should be
used; in a feed store, meat. As far as possible food other than the bait
should be inaccessible while trapping is in progress. The bait should be
kept fresh and attractive, and the kind changed when necessary. Baits
and traps should be handled as little as possible.
[Illustration: FIG. 10--Pit trap. _aa_, Rat run; _bb_, cover; _cc_,
position of weights; _dd_, rods on which covers turn.]
=Barrel trap.=--About 60 years ago a writer in the Cornhill Magazine
gave details of a trap, by means of which it was claimed that 3,000 rats
were caught in a warehouse in a single night. The plan involved tolling
the rats to the place and feeding them for several nights on the tops of
barrels covered with coarse brown paper. Afterwards a cross was cut in
the paper, so that the rats fell into the barrel (fig. 9 (1)). Many
variations of the plan, but few improvements upon it, have been
suggested by agricultural writers since that time. Reports are
frequently made of large catches of rats by means of a barrel fitted
with a light cover of wood, hinged on a rod so as to turn with the
weight of a rat (fig. 9 (2)).
=Pit trap.=--A modification of the barrel trap is the pit trap (fig.
10). This consists of a stout narrow box sunk in the ground so that the
top is level with the rat run. It is fixed with a cover of light wood or
metal in two sections, the sections fitting nicely inside the box and
working independently. They turn on rods, to which they are fastened.
They are weighted near the ends of the box and so adjusted that they
swing easily. An animal stepping upon the cover beyond the rods is
precipitated into the box, while the cover immediately swings back to
its place. Besides rats, the trap is well adapted to capture larger
animals, as minks, raccoons, opossums, and cats. It is especially useful
to protect poultry yards, game preserves, and the like. The trap should
be placed along the fence outside the yard, and behind a shelter of
boards or brush that leans against the fence.
=Fence and battue.=--In the rice fields of the Far East the natives
build numerous piles of brush and rice straw, and leave them for several
days until many rats have taken shelter in them. A portable bamboo
inclosure several feet in height is then set up around each pile in
succession and the straw and brush are thrown out over the top, while
dogs and men kill the trapped rodents. Large numbers are destroyed in
this way, and the plan with modifications may be utilized in America
with satisfactory results. A wire netting of fine mesh may be used for
the inclosure. The scheme is applicable at the removal of grain, straw,
or haystacks, as well as brush piles.
In a large barn near Washington, a few years ago, piles of unhusked corn
were left in the loft and were soon infested with rats. A wooden pen was
set down surrounding the piles in turn and the corn thrown out until
dogs were able to get at the rats. In this way several men and dogs
killed 500 rats in a single day.