Chapter 31: Wild boar management in Europe345
location, number of trap nights, type of bait used and duration
of pre-feeding before the traps are set (Saunders et al. 1993;
Williams et al. 2011).
Trapping has been employed in many projects aimed at
eradicating wild boar and wild pigs or at reducing their den-
sity. For instance, trapping was carried out as the main method
to reduce the local abundance of wild boar in Bulgaria during
an outbreak of classical swine fever and was found more reli-
able than hunting for reducing a wild boar population within a
short period (Alexandrov et al. 2011). Trapping was also used
as a method to decrease wild boar abundance from peri-urban
areas in Barcelona (Cahill et al. 2012) as hunting was not feasible
due to public opposition. In the Pinnacles National Monument
(California), trapping removed 70 per cent of the pig population
in the first three months, and the combination of trapping and
opportunistic shooting increased the efficiency of pig eradica-
tion (McCann & Garcelon 2008).
Once trapped, wild boar can be translocated to another
area or killed humanely. Translocations of problem animals,
including wild boar, are often advocated by the public to miti-
gate human–wildlife conflicts (e.g. Beringer et al. 2002; Conover
2002). However, despite their perceived humaneness, transloca-
tions may affect the welfare of the animals moved to another
area: translocated wildlife typically suffers from malnutrition,
dehydration, decreased immunocompetence, and increased
predation (Massei et al. 2010). Translocations also perpetuate
the ‘quick-fix’ solution and have the potential to spread diseases
to conspecifics, humans, domestic animals, and livestock: for
instance, Fernández-de-Mera et al. (2003) found that several
species of helminths were introduced into Spain from France
following the translocation of wild boar.
A non-lethal method that could be used in some contexts to
reduce wild boar abundance is fertility control through immuno-
contraception (Massei & Cowan 2014). Immunocontraceptives
induce the production of antibodies against hormones or pro-
teins essential for reproduction (Miller et al. 2008). These com-
pounds, which have recently been formulated as single-shot
vaccines, induce long-term infertility after a single injection.
For instance, gonadotropin-releasing hormone (GnRH)-based
vaccines stimulate the production of antibodies against GnRH,
which is in turn responsible for the production of sex hormones
that lead to ovulation and spermatogenesis (Miller et al. 2008).
In wild boar, a GnRH-based vaccine was found to be safe and
effective in inducing infertility for at least 3–6 years, after a single
injection, with no observable side effects on behaviour, welfare,
or physiology (Massei et al. 2008, 2012). Immunocontraceptives
have also been proposed as a possible means of decreasing
transmission of brucellosis and several other diseases (Killian
et al. 2007) by reducing the abundance of newborn, susceptible
animals within the population.
With a high level of public acceptance, fertility control
could be used to decrease numbers of wild boar, particularly
for isolated populations where immigration and emigration do
not affect the population dynamics. However, managing wild
boar populations by using injectable contraceptives could be as
expensive as trapping and thus is more likely to be confined to
small-scale, specific contexts where lethal control is not feasible
or desirable. Examples include wild boar populations in urban
areas or in national parks where hunting is not allowed, or where
lethal control could affect contact rates and spread of diseases.
When a reduction of wild boar density is required, different
control methods should be evaluated to assess their feasibility, sus-
tainability, costs, humaneness, and social acceptance (Engeman
et al. 2007; Massei et al. 2011). Compared to culling, fertility con-
trol is relatively slow in decreasing local abundance because the
benefits of this method can only be accrued after several years or if
this method is applied in conjunction with other population con-
trol options. For instance, fertility control could be used to keep
the density of wild boar at a set level once lethal control has been
applied. More research is ongoing to develop oral contraceptives
to increase the efficacy of fertility control applications for popula-
tion control. If oral, non-species-specific contraceptives become
available, the possibility of affecting non-target species must be
addressed. Wild boar-specific feeders such as the BOS™ (Boar
Operated System) are available as effective, species-specific devices
developed to deliver contraceptives and other pharmaceuticals to
wild boar (Massei et al. 2010; Ferretti et al. 2014) (Figure 31.5).Management for Hunting Wild Boar in
Enclosed Areas
Wild boar game enclosures are widespread in Europe and world-
wide (Dezorzova-Tomanova et al. 2006; Vicente et al. 2007; West
et al. 2009; Jánoska 2010; Andersson et al. 2011). Wild boar play
a significant role in hunting both in the wild and when enclosed.
However, the manner of managing boar differs in the wild and
in enclosed spaces.Technology and Habitat
Wild boar can be kept together with different wild ruminant spe-
cies in large enclosed parks which can be thousands of hectares,
or they can be kept alone in parks that are a few hundred hectares.
Wild boar enclosures can be operated by implementing either
a ‘unified’ or a ‘divided’ management. The first type keeps and
breeds wild boar in a large area of at least 200–300 ha; the average
recruitment in these circumstances is around 1.5–2 piglets/sow/
year. The goal is to reach a population density of 1 wild boar/ha
before the start of the hunting season so that 55–60 per cent of the
spring stock can be utilized for hunting. Parks that employ the
‘divided’ management are also known as storage parks. ‘Divided’
management often contain sow storage gardens, so-called piglet
gardens for separated piglets, and a garden for the ageing of tuskers
for hunting. With the use of piglet gardens, 3–3.5 piglets/sow can
be nurtured, which can reduce piglet mortality by 15–20 per cent
when compared to the unified method. (Jánoska 2010).
Wild boar parks should also satisfy the biological needs of the
animals by providing enough waterholes (for drinking and wal-
lows), shelters, and food sources. It is vital to have a well-composed
diverse flora of trees and underbrush for habitat in parks used for
hunting. It should be noted that where wildlife density is too high,
the underbrush will die or, at the very least, wither within one or
two years (Jánoska & Varju 2009; Lebocký & Petrás 2015). Game
fields are a crucial part of wild boar enclosures, which account for
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