Integrated feral pig control
In Victoria feral or wild populations of pigs (Sus scrofa) are declared as established pest animals under the Catchment and Land Protection Act 1994. Under the Act all landowners have a responsibility to prevent the spread of — and as far as possible eradicate, established pest animals from their land.
Feral pigs have been present in Australia since early European settlement. Their populations were originally concentrated around settlement areas but they have since spread across 45 per cent the mainland, and occur in all states and territories
Feral pigs affect large sections of Australian agriculture and the natural environment by:
- preying on lambs and wildlife
- destroying crops, pastures and native vegetation
- damaging waterways and causing reduced water quality.
Feral pig impacts are estimated to cost the Australian economy over $100 million annually.
Feral pig biology and behaviour
Before designing your feral pig control program, it is important to understand feral pig behaviour and characteristics:
- Feral pigs eat both meat and vegetable material (that is they are 'omnivorous').
- Feral pigs are highly intelligent and capable of adapting their behaviours to allow them to live in a wide range of habitats. Feral pigs change location and behaviour over the seasons of the year. They use different habitats to obtain shade and water and exploit seasonally abundant food resources.
- Feral pigs require a reliable and adequate supply of water, food and shelter.
- Feral pigs require food that is high in protein to reproduce.
- The reproductive potential of feral pigs is more similar to that of rabbits than to other large animals. Under favourable conditions, breeding can occur throughout the year and sows can produce two weaned litters every 12 to 15 months, with an average of 6 piglets per litter. This gives feral pigs the capacity to recover quickly from the effects of control programs or drought.
- Feral pigs form herds or 'mobs' based on a maternal hierarchy — a dominant female (sow) leads the group. The dominant sow will lead other members of the group to food, water and shelter. Adult males (boars) are mostly solitary. Groups of young males under 18 months of age will form 'bachelor' mobs.
- Feral pigs can travel long distances to find food or water or to escape hunting pressure.
See feral pig for more information about their characteristics and behaviour.
Managing feral pigs on your property
- Control feral pigs before they cause severe crop losses, vegetation damage, waterway sedimentation, soil erosion and livestock predation.
- Ensure your feral pig control program doesn't affect native wildlife.
- If any feral pig control work is to be undertaken that may result in disturbance of native vegetation, culturally significant areas or waterways. You must contact the responsible authorities prior to works being conducted. The responsible authorities may include Local government, Agriculture Victoria, Aboriginal Affairs Victoria or the local Registered Aboriginal Party, and the local Catchment Management Authority.
- If you are planning to use traps to control feral pigs — the trap specifications, trap checking times, provision of food, water and shade, and humane destruction of trapped feral pigs must be carried out in accordance with the requirements of the Prevention of Cruelty to Animals Act 1986 (POCTA) and associated regulations. Trapping has several animal welfare implications and anyone considering trapping should read Humane Vertebrate Pest Control.
- If you are planning to use dogs for feral pig control, be mindful that there are specific requirements for the use of dogs for hunting. Under Section 28 of the Domestic Animals Act 1994, a person must not set or urge a dog to attack, bite, rush at or chase any animal except when hunting in accordance with the Prevention of Cruelty to Animals Act 1986 (POCTA).
- If you are planning to use chemicals to treat feral pigs all applicable requirements of the Agricultural and Veterinary Chemicals (Control of Use) Act 1992 and Agricultural and Veterinary Chemicals (Control of Use) Regulations 2007 must be met. This includes adhering to the directions for use on the chemical label, keeping the relevant chemical use records and only using 'restricted use chemicals' if you hold the required Agricultural Chemical User Permit or other relevant permit. Chemical use record sheets and further information regarding agricultural chemical use can be found on chemicals.
Planning your program
Planning can maximise the effectiveness of feral pig control while minimising damage to other animals. Consider pig density, distribution and the habitat in which the feral pigs are living as this will determine what actions are appropriate. The following steps will help in planning.
Coordinate control work with your neighbours. The best results are achieved when neighbours work together to conduct simultaneous feral pig control across a landscape, rather than just on individual properties. Work on your property can be undermined by the inactivity of your neighbours. Talk to your neighbours and your local Landcare group to work out a plan for coordinated action.
- Identify feral pig feeding behaviour and activity areas in and around your property. Map these areas for future reference. Feral pigs are often found around watering points, wallows, waterways and swampy areas, areas with vulnerable livestock, plantations, crops and thick vegetation.
- Feral pigs can be monitored by constructing sand pads, using motion sensor cameras and measuring bait uptake at feral pig free-feed bait stations or by observing rooting damage.
- Feral pig density can also be assessed by ground-based or aerial counts.
- Assess the risks to non-target animals when implementing baiting or shooting.
- Establish a benchmark of the impact of feral pigs on your property. This will be used to measure the effectiveness of your control programs.
Use the information you have gained from monitoring to:
- target your control effort
- monitor the progress and success of your control program
- vary and improve your program.
It is important to continue monitoring on an ongoing basis to detect and treat any re-infestation of feral pigs on your property.
Use all the tools
Effective feral pig control uses all the available control measures that are suitable on your property. Every individual feral pig should be exposed to as many different control measures as possible to make your property an undesirable environment for feral pigs.
Consider seasonal movements of feral pigs and your ability to access areas of feral pig activity. Time your control program to manage feral pigs prior to the time of year when they cause the most damage.
Drier times when less food is available will be more suitable for baiting and trapping. Aerial shooting may be suitable during wetter seasons when food is plentiful.
Evaluate your success
Conduct a second round of monitoring after your control program:
- Are pigs still present?
- Are you still experiencing damage caused by feral pigs?
- Is the feral pig damage above or below acceptable thresholds?
- What is working well?
- What could be improved?
- Do you need to change your plan?
- Have you managed all the risks?
Continue monitoring on an ongoing basis. Feral pig populations will rebound quickly. Plan your pig control as a regular and ongoing component of your property management activities.
Feral pig control is time-consuming and there is no quick-fix solution.
There are a range of parasites and diseases present in Australia's feral pig population but none are likely to have any significant impact on the overall population.
New biological control agents are unlikely to be released due to the potential for non-target impacts on agricultural pig production industries.
Baiting is a useful technique to reduce feral pig populations. However, populations will quickly recover unless follow-up control.
1080 (sodium monofluoroacetate) is a lethal poison registered to control vertebrate rabbits, foxes, wild dogs and feral pigs in Victoria.
1080 is derived from a compound found in many Australian native plants. Some Australian native animals have a higher tolerance to 1080, depending on the species. Introduced species such as domestic dogs and cats, livestock and pest species such as rabbits, foxes, wild dogs and wild or feral pigs are highly susceptible to 1080 poisoning.
1080 pest animal bait products registered to control feral pigs in Victoria are available as commercially produced shelf-stable bait. Shelf-stable feral pig baits are designed to attract omnivores (such as feral pigs) but are less attractive to herbivores or carnivores.
To purchase and use 1080 Pest Animal Bait Products in Victoria you must have either an Agricultural Chemical Users Permit (ACUP) with a 1080 endorsement — or a Commercial Operators Licence (COL) with a vermin destroyer endorsement — or hold a valid Licence To Use Pesticides (LTUP) with an authorisation for the control of pest animals.
Non-target animals may be killed as a result of consuming 1080 bait or poisoned carcasses. Livestock should not have access to 1080 pest animal bait products. All baits must be used in accordance with the product label and the Directions for the Use of 1080 Pest Animal Bait Products in Victoria.
All uneaten and unused bait and poisoned carcasses must be disposed of as per the Directions for the Use of 1080 Pest Animal Bait Products in Victoria. 1080 baiting programs should not be implemented where they pose a risk of killing non-target species.
Anyone considering implementing a 1080 baiting program must read and adhere to the Direction for the use of 1080 pest animal bait products in Victoria.
HOGGONE feral pig bait was recently registered for the control of feral pigs in victoria and it contains a relatively new vertebrate pest toxicant called sodium nitrite. Once ingested, sodium nitrite induces the formation of Methaemoglobin by oxidising haemoglobin. This essentially reduces the blood's ability to carry oxygen throughout the body causing major organs including the heart and brain to shut down leading to death. Death typically occurs within 2 hours after bait ingestion. Available data shows feral pigs are particularly susceptible to sodium nitrite poisoning, but other species are also susceptible.
HOGGONE feral pig bait is the only product containing sodium nitrite that is registered for the control of feral pigs. You do not need to hold authorisation — for example, ACUP — to use HOGGONE feral pig bait, but like any other agricultural chemical it is recommended that users successfully complete a course in agricultural chemical use.
Although you do not need to hold authorisation to use HOGGONE feral pig bait, there are restriction for its use. The product label provides details of these restrictions as well as specific directions for use.
In order to further minimise any risks a thorough risk assessment should be undertaken before any HOGGONE feral pig bait is laid and all HOGGONE feral pig bait must be delivered in a purpose built bait hopper to reduce the chances of non-target species gaining access to bait material.
Free-feeding must be conducted before baiting to:
- familiarise feral pigs with the bait product
- to calibrate the baiting rate (to ensure that sufficient baits are available for all pigs)
- allow the pest manager to monitor for non-target species.
Free-feeding can be conducted with unpoisoned grains or commercially available shelf stable baits. Free-feed baits can be laid in cluster-bait piles or in specially constructed bait stations depending on the bait being used.
Once feral pigs begin taking trail baits they should be reduced to cluster-bait stations to ensure bait is presented across the smallest possible area.
Due to natural wariness, feral pigs may sometimes fail to take baits. Should feral pigs fail to take bait, postpone the baiting program until conditions are better suited for baiting (when alternate feed is scarce).
Poison bait should be laid at the same location as free-feeding occurred. If using bait stations, initially use free feeds to allow time for feral pigs to learn how to access the bait inside the bait station — this is critical. Once the feral pigs are familiar with the bait stations, replace the free-feeds with the poisoned baits.
Bait stations that exclude access by non-target species but allow access by feral pigs may reduce the potential to harm to non-target animals. They can also help protect the bait from the weather elements.
Exclusion fencing is a non-lethal way of protecting high-value areas from feral pigs however it is expensive and not practical at a large scale. Fences must be strong enough to exclude robust animals like feral pigs.
Unfortunately no fence will guarantee protection from feral pigs especially if they are already habituated to accessing the food source or the area you wish to protect. Fences need to be regularly checked and maintained as a fence becomes ineffective once a breakthrough occurs.
Construct a fence around areas or assets you wish to protect from feral pigs and to restrict the ability of feral pigs to move from areas where they rest to areas where they feed.
Electrified strands can be added as outriggers or staked in front and will greatly improve the effectiveness and longevity of the fence. Consider wire spacings in relation to the size of the feral pigs to be excluded.
It is best to have fences erected by experienced or professional fencers.
While shooting is the most target-specific and humane form of feral pig control, hunting alone will not achieve long-term pig control. Shooting is likely to quickly educate pigs making them wary. This often results in difficulty estimated feral pig numbers as they will be less visible.
Due to the high reproductive capacity of feral pigs during favourable conditions, population numbers are likely to recover to original densities after only 1 year (or less) following shooting campaigns.
Ground shooting of feral pigs is the most common form of control. However, it is highly labour intensive and is likely to be opportunistic and uncoordinated. Ground shooting is unlikely to reduce the feral pig population enough to reduce the impacts. Where small isolated populations of feral pigs exist, a coordinated ground shooting campaign may provide a useful management tool.
Attractants such grain is used by hunters to attract feral pigs to an area where they can be shot. This approach can be useful for isolated small populations particularly when coupled with the use of a motion sensing camera and a thermal rifle scope. The camera can help determine when the pigs are active and the thermal scope helps prevent your detection.
Aerial shooting of feral pigs from a helicopter is suitable for controlling feral pigs over large areas where there is a high feral pig population density.
It is highly target-specific, humane and cost effective where the terrain is suitable to detect feral pigs on the ground and where shooting is carried out by an appropriately trained and skilled operator.
Aerial shooting is not cost effective when populations are low due to the difficulty in finding widely distributed animals, nor is it suitable for areas with closed tree canopies.
The use of firearms to control feral pigs must conform to relevant firearm legislation and be integrated with other control methods.
Trapping is an effective method for managing feral pigs where poisoning is not feasible. Well-designed traps can be feral pig specific, allowing access to feral pigs but preventing access to non-target species.
There are a range of trap designs including silo, panel or box traps which basically consist of an anchored steel mesh enclosure with a lure or bait that the target feral pigs find attractive.
Pigs gain access through a one-way entrance and are then unable to escape. To comply with animal welfare legislation, traps must be checked regularly to minimise the time that trapped feral pigs or non-target species are held. Trapped feral pigs must be quickly and humanely destroyed.
Trapping success is affected by season, food availability and trap placement in the landscape. Free-feeding is required to familiarise feral pigs with a trap and coax greater numbers of feral pigs into the trap before it is set.
Hunting activity in the area will make trapping less effective. Trapping requires considerable time and cost for construction and ongoing maintenance of traps. Some feral pigs may become 'trap shy' and prove difficult to capture requiring alternative control methods.
Any trapping of feral pigs must be carried out in accordance with the requirements of the Prevention of Cruelty to Animals Act 1986 (POCTA) and associated regulations.
Trapping has several animal welfare implications and anyone considering trapping should read Humane Vertebrate Pest Control.
Animal carcasses should be buried or burnt to prevent feral pigs feeding on them. Presence of carcasses may attract feral pigs onto your property.
In areas affected by feral pigs, small lambing paddocks should be used to allow easier monitoring of the flock and reduce the chances of young lambs or kids being left unattended a long way from their mothers. Lambing paddocks situated close to the house are also easier to check frequently.
Other management techniques
Changes in farming production systems may be considered as a last resort where the impacts of feral pigs are extremely difficult to control.
Wethers, billy goats, or females without young and cattle are less vulnerable to predation by feral pigs than breeding stock.