Poisoning operations for the control of predatory animals should be
limited strictly to areas where there is urgent need. They will not
be undertaken under the direction of the Biological Survey where
trapping or other means of control are practicable and the cost is not
prohibitive.
The handling of poisons should be intrusted only to properly trained
men working under the supervision of the Bureau of Biological Survey.
Poison stations set for coyotes and wolves should be placed away from
the timbered and well-watered areas that are frequented by foxes,
raccoons, skunks, minks, and other valuable forms of carnivorous
animals.
In many agricultural sections poisons should not be used at all because
of the obvious risks.
The methods of handling poisons developed and used by the Biological
Survey can be employed most effectively and economically in controlling
predatory animals at proper seasons in regions where conditions are
favorable. Poison is especially suitable for winter use against
predators on some of the great stock ranges of the West, as it can then
be employed with little or no danger to useful life. The cost of the
same measure of control by any other known means would be practically
prohibitive.
The control of predatory animals is an exceedingly difficult and
costly task, and the use of poisons in this work, particularly under
experienced supervision, materially reduces the expense. When properly
used, poison should not be more destructive to other species than the
use of traps, and in some cases it has been found to be even less
harmful and more humane.
Hunters should take every precaution to protect harmless and valuable
mammals and birds and should be familiar with the antidotes for each
poison used.
Only strychnine as processed by the Biological Survey should be used
in operations against predatory mammals, because it can be handled
safely, is constant in effect, and, since it kills quickly, its action
is humane.
Baits made of small pieces of perishable fat should be used almost to
the exclusion of others by field men and cooperators of the bureau.
They should be systematically placed about "decoy stations" consisting
of carcasses of worn-out horses or other useless animals or pieces of
meat. Wherever possible they should be placed in slight depressions and
covered with thin flat stones, pieces of hide, or other light material,
as coyotes and wolves can easily detect them under such cover, but they
are thus made inaccessible to birds.
Stations where poison is placed should be posted to warn owners of
stock or valuable dogs of the danger. Conspicuous warning signs such as
those furnished by the Bureau of Biological Survey in its cooperative
work should be used for the purpose.
In dispensing poisons for the use of cooperators in predatory-animal
control, Biological Survey field leaders are instructed to exercise the
greatest care to make sure of the integrity, honesty, and cooperative
spirit of those requesting supplies. When the leader has satisfied
himself as to the intent of the cooperator, he should keep in close
touch with him and observe his methods, to make sure that the poison
is being properly used and that no supplies are left in his possession
after cooperative work has been terminated.
Studded stations, or those in which the poison is placed in parts of
the carcass instead of about it, are to be used only under especially
favorable conditions. Their use is sometimes justified along the known
runways of predatory animals on high barren mountain ridges, high
benches, or stock driveways that can not be visited by the hunter after
the first heavy snowfall. Such stations should be at some distance from
timber, to make remote the danger of poisoning fur bearers. As soon
as trails are open in spring, the hunter is directed to revisit such
stations and bury or burn all the baits.
All predatory-animal hunters must visit their poison stations as
frequently as possible, and except under extraordinary conditions
should avoid making long poison lines. Baits that have become rancid
should be destroyed, and on completion of the poisoning work a general
clean-up must be made, and all baits possible destroyed. The use of
perishable fat baits is particularly recommended for the reason that
they are readily disposed of naturally, for those that can not be
located usually disintegrate in warm weather and become harmless after
they have melted and soaked into the ground.
Bears are ordinarily classed as game animals and are protected as
such. Only when they are doing material damage should they be taken,
and then by traps or by aid of dogs, and not by poison. State laws on
the subject must be observed. Field men and cooperators must exercise
the greatest possible care to kill only those individuals responsible
for damage, and must remove no more bears from a locality than it
is absolutely necessary to take in order to stop the destruction of
livestock.
In placing traps for the capture of injurious wild animals every
possible precaution is to be taken to avoid the accidental capture of
valuable game and fur-bearing animals and other harmless or beneficial
forms of wild life. Hunters working under the supervision of the
Biological Survey are instructed to visit their trap lines
as frequently as possible and to liberate game animals and
foxes, badgers, skunks, martens, minks, raccoons, and other animals
accidentally caught, unless they are so injured that they can not
survive. In occasional individual cases, however, where fur bearers do
serious injury to livestock or poultry, it is permissible to trap and
kill them if in accordance with State laws.
The most nearly humane traps available should be used, and trap lines
should be so placed that they can be visited at frequent intervals, to
avoid any unnecessary suffering, injury, or loss of trapped animals.