Review of the management of feral animals and their impact on ...

5.9 Management <strong>of</strong> foxes
Eradication <strong>of</strong> foxes is not currently considered a viable proposition for mainl<strong>and</strong>
Australia due to <strong>the</strong>ir population size <strong>and</strong> expansive range. A variety <strong>of</strong> fox control
techniques are used including trapping, shooting, poisoning, den fumigation,
exclusion fencing <strong>and</strong> changed farming practices. The most effective measures for
conservation <strong>and</strong> protection <strong>of</strong> endangered species are poison baiting <strong>and</strong> exclusion
fencing. The effectiveness <strong>of</strong> <strong>the</strong>se can be greatly enhanced by developing buffer
zones <strong>of</strong> up to 20 kilometres where foxes are held at a low density to decrease <strong>the</strong> risk
<strong>of</strong> inward migration rapidly replacing foxes killed (Saunders et al. 1995).
Bounty systems
The payment <strong>of</strong> a bounty or bonus upon presenting pro<strong>of</strong> <strong>of</strong> <strong>the</strong> destruction <strong>of</strong> a pest
animal has been frequently used against foxes (Rolls 1969, Whitehouse 1977, Lloyd
1980). These bounty systems have been shown to be an ineffective form <strong>of</strong> control
<strong>and</strong> provide no long-term relief from fox <strong>impact</strong>s (Smith 1990, Braysher 1993,
Saunders et al. 1995). Where private l<strong>and</strong> adjoins or contains important wildlife
habitat, assistance or encouragement to l<strong>and</strong>holders <strong>and</strong> <strong>the</strong> development <strong>of</strong> incentives
to promote fox control on private l<strong>and</strong> may be appropriate, especially if <strong>the</strong> property
forms part <strong>of</strong> a buffer zone to protect threatened species populations. This should be
achieved through incentives such as resources to assist with control, ra<strong>the</strong>r than
provision <strong>of</strong> bounties.
Poison baiting
In most situations, poison baiting is <strong>the</strong> most effective method <strong>of</strong> reducing fox
numbers <strong>and</strong> <strong>impact</strong>, although a major drawback is that it may affect native carnivores
<strong>and</strong> scavengers <strong>and</strong> also domestic pets. The benefits <strong>of</strong> this control method are
confined to <strong>the</strong> baited area <strong>and</strong>, unless some barrier prevents reinvasion, last only for
as long as baiting is regularly applied. A variety <strong>of</strong> toxins <strong>and</strong> bait types have been
used, however only 1080 <strong>and</strong> strychnine are registered for fox control in Australia.
1080 is now <strong>the</strong> only widely recommended poison for fox control <strong>and</strong> <strong>the</strong> use <strong>of</strong>
strychnine is being phased out. A variety <strong>of</strong> baits are used to deliver poison to foxes,
including injected eggs, dried meat baits, fresh meat, <strong>and</strong> commercial products (eg
Fox<strong>of</strong>f baits). However meat is <strong>the</strong> primary bait used to deliver poisons to foxes. It is
very palatable to foxes, easily obtained <strong>and</strong> h<strong>and</strong>led, <strong>and</strong> is relatively target-specific,
being attractive only to a limited number <strong>of</strong> carnivores <strong>and</strong> omnivores. Targetspecificity
can be fur<strong>the</strong>r enhanced by <strong>the</strong> manipulation <strong>of</strong> size <strong>and</strong> by drying. Tests
have shown that smaller carnivorous marsupials <strong>and</strong> scavenging birds such as ravens,
cannot consume dried meat baits as <strong>the</strong>y are too tough <strong>and</strong> stringy (Calver et al.
1989). However, <strong>the</strong> assumption that dried baits maintain <strong>the</strong>ir consistency in <strong>the</strong>
field, <strong>and</strong> hence <strong>the</strong>ir target-specificity, has not been demonstrated in <strong>the</strong> higher
rainfall areas <strong>of</strong> south-eastern Australia. Surface application <strong>of</strong> manufactured or fresh
meat baits, which are equally or more attractive than dried meat baits, may put nontargets
at risk because <strong>the</strong>y can be readily ingested. Dried meat is <strong>the</strong> preferred bait
material in Western Australia especially for aerial application where native fauna have
a tolerance to 1080. Manufactured baits, such as Fox<strong>of</strong>f, are now used extensively
throughout south-eastern Australia. They can be easily distributed, stored on <strong>the</strong> shelf
until required, have accurate amounts <strong>of</strong> poison <strong>and</strong> <strong>the</strong> potential to include
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