Perspective: methods for controlling fox populations

by Shannon Dundas.  Baiting using sustained, coordinated, broad-scale baiting programs between government agencies and private landowners is the most effective way to control red fox numbers.

For agricultural areas, effective fox control will reduce stock losses.  Effective predator control is also essential to enable native species to survive within their natural habitat, a much more feasible long-term option compared to expensive predator-free enclosures.

Unfortunately, many native species interfere with ground-distributed fox baits. They eat baits or and can move them from bait stations, disrupting bait-take by foxes as well as monitoring of bait-take. The quokka (Setonix brachyurus) is just one native species of conservation significance that benefits from ongoing ground-based poison baiting to control foxes. Unfortunately, quokkas also seem to have a penchant for these baits, and the greater the number of quokkas there are, the more baits they will consume.

In Western Australia, sodium fluoroacetate (more commonly known as ‘1080’) is the best option for a targeted poison because many native species have high tolerances to 1080 due to the natural occurrence of this compound in several native plant species. Quokkas have a high tolerance to the poison used and therefore should not suffer any side effects themselves, but they are consuming baits meant for foxes, sometimes just hours after they have been distributed.

In a recent study, fox baits were monitored by regular visits and remote cameras were positioned at seven forest sites in WA near Jarrahdale, Dwellingup and Collie within areas inhabited by quokkas. In total, 99% of baits were observed being taken by species other than foxes: 95% were taken by native fauna and 4% by introduced pigs and black rats. Additionally, baits did not last very long in the environment, with 62% of 299 baits monitored taken on or before the first night after distribution, and 95% taken within seven days.

Control programs need to be continually assessed and adjusted, especially during long-term baiting programs.  This includes measuring fox presence in addition to assessing population changes in native species, which may be influenced by other non-predation related factors such as climate and disease.

Further research is needed to improve baiting methods

Further research is required to investigate methods for improving targeted ground bait delivery towards foxes while reducing interference from other species.

Feral cats are also a predation concern and ideally control programs should target both species, although broad-scale cat control is proving to be more of a challenge.

Options such as aversion training of non-target species to incite negative associations towards fox baits could potentially allow baits to remain in the environment for longer periods; therefore increasing opportunities for foxes to find and consume a poison bait.

How baits are presented could help to reduce the likelihood of other animals to interact with baits, but could also help to make baits more attractive to foxes.  We especially need something to make baits more attractive than alternative available food sources.

Baiting will be less effective when alternative food sources (e.g. sheep carrion) is abundant. Image: Murdoch University
Baiting will be less effective when alternative food sources (e.g. sheep carrion) is abundant. Image: Murdoch University

Overall, improvements are required to further enhance fox control programs in WA which rely on ground baiting.

Effective control of introduced predators is of paramount importance to ensure the ongoing preservation of our native species in their natural habitats, as well as reducing stock losses in agricultural areas.

Dr Shannon Dundas is a Post-Doctoral Research Fellow at the School of Veterinary and Life Sciences at Murdoch University.

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