Environmental Engineering Reference
In-Depth Information
Live trapping is often ine cient compared with kill trapping or poisoning,
but nonetheless has been the sole method used in several successful eradication
attempts, usually because the lethal options threatened native non-target species.
Coypu (
Myocaster coypus
) were removed from England by trapping (Gosling and
Baker 1989). Mink (
Mustela vison
) have been removed from Hiiumaa Island in the
Baltic by lethal trapping (Macdonald and Harrington 2003), and from the south-
ern islands of the Hebrides by live-trapping (S. Roy, pers. comm.). A proposed
attempt to eradicate North American beavers (
Castor canadensis
) from the seven
million hectares they now occupy in Tierra del Fuego (where they were introduced
in 1948; Anderson
et al
. 2006) would have to rely on trapping (and shooting)
because these traditional tools are the only methods proven to eff ectively control
and locally eliminate beavers in parts of their natural range. h ere is major uncer-
tainty whether such simple tools will be as eff ective at huge scales, as they were
developed for local extirpation (Parkes
et al
. 2008a).
However, most successful eradication attempts that have included traps have
also used additional control methods, often because some animals cannot be
caught in traps. For example, on Santa Cruz Island, California, 13% of 1421 feral
pigs (
Sus scrofa
) were not caught in traps in a trial in a 2250-ha fenced area (Sterner
and Barrett 1991), and only 16% of pigs were trapped in the fi nal eradication over
the whole island in 2006 (Parkes
et al
. 2008c). Where there are no technically feas-
ible or socially acceptable alternatives to trapping, the resulting inability to catch
any trap-shy animals seems to be a major constraint in eradicating some invasive
species—musk shrews for the former reason (Seymour
et al
. 2005) and several
pests in Japan for the latter reason (Ikeda 2006).
Research on lures has also advanced with modern chemistry, although the 'privie
parts of a vixen mixed with galbanum' as recommended by Mascall (1590) still
have their use in, for example, the use of the castor glands of beavers to attract them
to traps. Successful control of insects using pheromones as lures has fewer coun-
terparts in terrestrial vertebrate pest management, although it is an option for fi sh
that rely on chemical cues to fi nd spawning sites (e.g. lampreys in the Great Lakes;
Li
et al
. 2003). Food is most commonly used to lure animals, but visual, auditory,
and olfactory lures are also widely used.
12.3.3.2 Shooting
The slings and arrows of the past have evolved into fi rearms. Modern fi rearms and
knowledge of ballistics allow several specialist applications to control pests, such
as in urban areas where human safety when shooting unwanted animals is para-
mount, e.g. white-tailed deer (
Odocoileus virginianus
) in suburban North America
(De Nicola
et al
. 1996). Other than the ongoing development of telescopic, low-
light, and infrared sights, the main improvements in using fi rearms methods have
been smarter applications using modern techniques such as radio-telemetry and
GPS to track the hunters, dogs, helicopters, and target animals, or the use of Judas-
animals for social species to enable hunters to locate con-specifi cs associating with
the telemetered animals (e.g. Campbell
et al
. 2005).
