Trapping of feral pigs

Standard Operating Procedure – PIG001

Background

Feral pigs (Sus scrofa) have a significant impact on the environment and agricultural production and are a potential reservoir and vector of exotic diseases. Control methods include poisoning, trapping, exclusion fencing, ground shooting and shooting from helicopters. Commercial harvesters also use traps to capture pigs for export as wild boar meat.

Prior to trapping, free feeding of bait is offered at sites where pigs are active. After selecting a suitable site, a trap is then erected and free feeding is continued for a number of days before the trap is set. After pigs have been caught they are shot whilst still inside the trap. Good trapping techniques may enable whole groups of pigs to be caught at one time with minimal impact on non-target animals.

This standard operating procedure (SOP) is a guide only; it does not replace or override the legislation that applies in the relevant state or territory jurisdiction. The SOP should only be used subject to the applicable legal requirements (including OH&S) operating in the relevant jurisdiction.

Application

  • Trapping should only be used in a strategic manner as part of a co-ordinated program designed to achieve sustained effective control.
  • Trapping is effective for reducing numbers of feral pigs in areas where 1080 poisoning cannot safely be used or when pig populations are relatively low. It is often used as a follow-up control method after initial reduction of high pig populations.
  • It is most successful when food resources are limited.
  • Maintenance of traps is time consuming. Therefore, it is only suitable to use traps in situations where the operator has time to check them on a regular basis.
  • Shooting of pigs should only be performed by skilled operators who have the necessary experience with firearms and who hold the appropriate licences and accreditation. Storage and transportation of firearms and ammunition must comply with relevant legislation requirements.

Animal Welfare Considerations

Impact on target animals

  • Traps should be set up at sites where vegetation can provide shade and shelter. Pigs have poor thermoregulation and can suffer greatly when exposed to extremes of heat and cold.
  • To minimise the possibility of dehydration and heat or cold stress, all traps must be inspected daily. Shade cloth or hessian can be used for protection during extremes of weather.
  • The trap should be constructed in a way so as not to cause injury from loose wire, sharp edges or malfunctioning gates.
  • Captured animals must be approached carefully and quietly to reduce panic, further stress and risk of injury.
    Trapped pigs must be destroyed by shooting as quickly and humanely as possible.
  • If lactating sows are caught in a trap without their young, efforts should be made to find dependent piglets and kill them quickly and humanely.

Impact on non-target animals

  • Traps are designed for the capture of feral pigs and so pose only a small risk of capturing other species. Use of a pig-specific gate trip mechanism minimises the risk of catching some species e.g. cassowaries and wallabies. Placement of a steel post across a funnel trap entrance at a height of 1 m above the ground will prevent cattle from entering.
  • Live non-target animals caught in traps must be examined for injuries and signs of illness or distress and dealt with as follows:
    Animals which are unharmed or have only received minimal injuries such as minor cuts or abrasions should be immediately released at the site of capture.
  • Animals which have more severe injuries or which are suffering from thermal stress should receive appropriate attention. An animal suffering from thermal stress can initially be placed in a suitable quiet holding area which provides warmth or shade to allow recovery before release. Animals with treatable injuries that cannot be immediately released or those failing to recover from thermal stress should be presented to a veterinarian or a registered wildlife carer for treatment.
  • Animals that have injuries which are untreatable or which would compromise their survival in the wild should be euthanased using a technique that is suitable for the species. For more information on euthanasia techniques refer to Methods of Euthanasia.
  • If a trap continually catches non-target animals, an alternative bait attractant could be considered or the trap could be moved to another site where it will have minimal effect on other species.

Health and safety considerations

  • During construction of traps, operators should be wary of the risks of injury from lifting heavy items. Leather gloves and eye protection will help prevent injuries from wire, steel panels and hammers.
  • Firearms are potentially hazardous. All people should stand well behind the shooter when pigs are being shot. The line of fire must be chosen to prevent accidents or injury from stray bullets or ricochets.
  • Care must be taken when handling pig carcasses as they may carry diseases such as leptospirosis, Q fever, brucellosis, sparganosis, melioidosis and tuberculosis that can affect humans and other animals. Routinely wash hands after handling all carcasses. Carcasses can be heavy (>100 kg), so care must be taken when lifting/dragging.
  • Never enter a trap with a captured adult pig. Feral pigs can be aggressive and will attack, especially in situations when they, or their dependent piglets, are distressed or threatened.
Carpentaria Land Council rangers with a cache of feral pigs

Carpentaria Land Council rangers with a cache of feral pigs

Equipment required

Traps

  • Several trap designs exist, differing mainly in their gate construction. These include the silo trap, the drop-gate trap, the panel trap and the box trap. All are basically an enclosed area with a one-way gate
  • It is best to use steel mesh with a small grid size eg 50 mm x 75 mm or 50 mm x 100 mm. A grid larger than this will damage the pigs’ snouts if they charge the mesh.
  • The minimum height needs to be 1.5 m.
  • Entrance to the trap can be a funnel entrance, a tripped gate or a pig specific trigger.
  • Choice of trap design will depend upon habitat, material available and accessibility to site.
  • Details of trap specifications and construction can be obtained from relevant State pest control manuals and guidelines, for example:
    • NSW Agriculture Agfact A9.0.15 Feral pigs: Trapping in NSW (1989)
    • NSW Agriculture Pest Control Manual (2003)
    • QLD NRM Facts Control of feral pigs (2001)

Bait

  • Bait preferences can vary from area to area. Current diet will sometimes determine how readily the pigs will accept an alternative food.
  • Pigs will be more attracted to bait with a strong odour.
  • Bait can include grain, or fermented grain (eg. wheat, oats, barley or triticale that has been soaked in water with molasses added), commercial pig or poultry pellets, vegetables and fruit.
  • Feeding meat or carcasses to feral pigs for the purposes of control may be illegal in some jurisdictions.
  • Large amounts of bait will be required; around 10—20 kg each time the trap is set.

Firearms and ammunition

  • Smaller calibre rifles such as .22 magnum rimfire with hollow/soft point ammunition are adequate for euthanasia of pigs at short range (<5 m).
    12 gauge shotguns may also be used with shot sizes of SG or SSG for large pigs over 40 kg, and BB or AAA cartridges for small pigs less than 40 kg.

Procedures

Selection of trap sites

  • Free feeding should be undertaken at sites where pigs are active, for example, near watering points, holes in fences, wallow areas or old carcasses that pigs are feeding on. This helps to retain pigs in the area and will give an indication of the most suitable trap site. Leave 3 to 10 kg of bait at each selected site. If necessary a trail of bait can be used to lure pigs to a chosen trap site.
  • Cease any activity in the area that will disturb normal feeding behaviour eg. shooting, use of dogs or chasing.
    If possible, choose a site that is in a shady area with as much natural vegetation as possible.

Placing the trap

  • Build the trap at a site where bait is being regularly taken.
  • Place fresh bait both inside and outside the trap to keep pigs feeding for 1 to 2 days.
  • Once the pigs have become accustomed to the trap and are still regularly feeding, only place bait inside the trap. Keep feeding until all pigs within a group are going into the trap to feed before it is actually set. This may take 1 to 2 weeks.

Setting the trap

  • Once bait is being taken inside the trap, set each evening and check the following day, preferably in the morning.
  • Continue to set the trap each evening until no more pigs are caught.A change of bait may be tried to entice more pigs, with free-feeding again for 1 to 2 nights before activating the trap.
  • Traps can be left at permanent sites and reactivated when fresh pig activity is detected or they can be moved to new sites depending on requirements.
    Some baits e.g. grain, may attract birds. Where this happens, lightly cover the bait with vegetation. Alternatively, grain that has been dyed green may help to deter consumption by birds.

Shooting of pigs

  • Caught pigs should be destroyed by shooting inside the trap.
  • Shooting must be conducted to cause sudden and painless death with minimum distress to the animal. Only head shots are acceptable.
    The shooter should approach the animals in a calm and quiet manner.
  • To prevent unnecessary agitation of the trapped pigs, other people should keep away from the area until shooting is completed.
  • DO NOT SHOOT THROUGH THE TRAP. To maximise the impact of the shot and to minimise the risk of misdirection the range should be as short as possible.
  • Never fire when the pig is moving its head, be patient and wait until the pig is motionless before shooting. Accuracy is important to achieve a humane death. One shot should ensure instantaneous loss of consciousness and rapid death without resumption of consciousness.
  • Shots must be aimed to destroy the major centres at the back of the brain near the spinal cord. This can be achieved by one of the following methods (see diagrams – recommended shot placements, side view skeleton and head shot frontal).

For smaller pigs

Frontal position

The firearm should be aimed at a point midway across the forehead and about 2cm above the level of the eyes. The bullet should be directed horizontally into the skull.

For larger pigs

  • These methods are preferred for adult pigs due to the heavier bone structure of the front of the skull.
Behind the ear
  • The firearm is aimed at a point behind the ear directed towards the opposite eye.
Temporal position
  • The firearm is aimed from the side of the head so that the bullet enters the skull at a point midway between the eye and the base of the ear on the same side of the head. The bullet should be directed horizontally into the skull.
  • Death of shot animals should always be confirmed by observing at least 3 of the following:
    • absence of rhythmic, respiratory movements
    • absence of eye protection reflex (corneal reflex) or ‘blink’
    • a fixed, glazed expression in the eyes
    • loss of colour in mucous membranes (become mottled and pale without refill after pressure is applied).
  • If death cannot be verified, a second shot to the head should be taken immediately.
  • If small piglets (>5 kg) are caught in the trap, the adult pigs should be shot first and then the piglets shot – preferably with a shotgun since they are small targets and likely to be moving rapidly around the pen.

Disposal of carcasses

  • Carcasses should be removed from the trap. Although pig carcasses can attract others into a trap, they are not the most effective bait to catch all pigs in an area.

References

  1. Agriculture Notes (2001). Code of accepted farming practice for the welfare of pigs. Bureau of Animal Welfare. Department of Natural Resources and Environment, Victoria.
  2. Department of Natural Resources and Mines (2001). NRM facts: Control of feral pigs. Department of Natural Resources and Mines, Queensland.
    AUSVETPLAN (1996). Operational Procedures Manual: Destruction of animals. Agriculture and Resource Management Council of Australia and New Zealand.
  3. Blackmore DK, Bowling MC, Madie P, Nutman A, Barnes GRG, Davies AS, Donoghue M and Kirk EJ (1995). The use of a shotgun for the emergency slaughter or euthanasia of large mature pigs. New Zealand Veterinary Journal. 43; 134-137.
  4. Choquenot D, McIlroy J and Korn T (1996). Managing Vertebrate Pests: Feral Pigs. Bureau of Resource Sciences. Australian Government Publishing Service, Canberra.
  5. Hamrick B, Smith M, Jaworowski C and Strickland B (2011). A landholder’s guide for a wild pig management: Practical methods for wild pig control. Mississippi State University, Mississippi.
  6. Lukins BS (1989). Feral pigs: trapping in New South Wales. Agfact A9.0.15. New South Wales Agriculture.
  7. McGaw CC and Mitchell J (1998). Feral pigs (Sus scrofa in Queensland). Pest status Review series – Land Protection. Department of Natural Resources and Mines, Queensland.
  8. Mitchell J (2011). Feral pig control. NQ Dry Tropics, Townsville, Queensland.
  9. Standing Committee on Agriculture, Animal Health Committee (1991). Model Code of Practice for the Welfare of Animals: Feral Livestock animals – Destruction or Capture, Handling and Marketing. CSIRO, Australia.

The Centre for Invasive Species Solutions manages these documents on behalf of the Environment and Invasives Committee (EIC). The authors of these documents have taken care to validate the accuracy of the information at the time of writing. This information has been prepared with care but it is provided “as is”, without warranty of any kind, to the extent permitted by law.

Connect with Government

It is important to connect with the relevant government authorities to ensure you have the right permits in place prior to undertaking your management program.

Connect

How to reference this page:

Trudy Sharp, 2012. Trapping of feral pigs. Standard Operating Procedure. PestSmart website. https://pestsmart.org.au/toolkit-resource/trapping-of-feral-pigs accessed 28-10-2020

FURTHER RESOURCES AND INFORMATION

It is important to contact the relevant federal, state or territory government agency using our connect section, prior to undertaking management.

In this video below Jason Neville and Paul Meek discuss and demonstrate the use of both a silo mesh or heat-shaped trap and the panel trap for catching feral pigs.

Below is some further additional information on feral pig trapping types and methods

Trap types

Panel, silo and box traps are the different types of traps currently available. A panel trap is a series of weldmesh panels wired together and supported with steel posts at the corners and panel centres. The size and shape of the panel trap can be changed by removing or adding panels so that rocks and stumps are avoided. Panel traps are relatively easy to construct, dismantle and transport.

A silo trap is built from a continuous mesh and is stronger than the panel trap while being flexible enough to prevent pigs from climbing out or breaking the mesh.

Silo traps are more suitable for semi-permanent trap sites because they are more difficult to construct, dismantle and transport than the other designs.

A box trap is portable and designed to fit onto the back of a standard 4WD tray back. It is particularly useful on smaller properties. The easy relocation of box traps makes them ideal for feral pig control, as seasonal movement of pigs caused by changing food availability means that traps often need to be moved to where the pigs are. Steel posts used at the corners of the box trap also prevent pigs from lifting the trap.

Trapping methods

Trapping is a process, not an event. Trapping success depends on several key components such as timing, location, bait material and free feeding. Trapping is most successful when alternative food resources are limited. An ideal trapping site is in the vicinity of recent pig activity, which tends to be in shaded areas of thick cover close to a water source. Trap sites should also be accessible by vehicle so pest controllers can carry large amounts of bait to the trap.

FPFS5 Image 1

To maximise the probability of pigs encountering traps, sufficient numbers of traps need to be distributed in a given area. Mitchell recommends that traps be set out in a circuit to make daily checking easy2.

Grain (wheat, oats or barley with molasses or Carasweet® added) is often used as bait material. To improve bait attractiveness to pigs, grain may be soaked in water for at least 3-5 days to ferment. This will produce a strong odour and pigs will be more likely to find the bait. In some jurisdictions (eg Qld), it is illegal to directly feed animal meat or meat by- products to feral pigs. Operators will need to use a large amount of bait each time the trap is set (around 10-20 kg), so it is best to use materials that are readily available at little or no cost (eg discarded bananas in North Queensland).

The success of trapping also depends on free-feeding before setting a trap. The goal of free feeding is to accustom pigs to the new food source and attract them to the trap site, and importantly, to get all of the pigs in a group conditioned to entering and leaving the trap unharmed. Some pigs are trap-shy, especially older pigs and pigs that have been previously trapped and released. Usually one to two weeks of free feeding is necessary before the entire group will enter the trap.

Once bait is continually being taken from a site, trap materials should be left for 2-3 days so that pigs become familiar with the smell of the steel mesh. The trap can then be partially erected with the gate open and poisoned bait placed inside the trap. If pigs hesitate to enter the trap at first, some bait material should be placed outside the door or laid in a trail leading to the trap. Aromatic attractants such as vanilla essence, aniseed and creosote or sump oil, can also be added to bait materials. A few different bait types such as bananas, mangoes, pumpkins or rockmelons, can also be used if readily available.

Traps can also be incorporated into existing fence lines to funnel pigs toward the traps. The use of dogs will be counterproductive while trapping because they push pigs away from traps. Human activity at the trap sites should also be kept to a minimum. Ideally, remote cameras should be used to ensure the entire mob is readily feeding from the trap before it is set.

FPFS5 Image 2

Once traps are set, animal welfare considerations need to be addressed. It is important to inspect them daily to release non-target animals as quickly as possible if they are trapped. Trapped pigs should also be removed as quickly and humanely as possible to prevent dehydration and heat/cold stress. Captured pigs need to be approached in a calm and quiet manner to prevent their unnecessary agitation, panic, stress and risk of injury. When shooting captured pigs inside the trap, only head shots are acceptable. The pig needs to be shot when it is motionless – never shoot when the head is moving. Smaller calibre rifles (eg .22 magnum rimfire with hollow/soft point ammunition) are recommended for euthanasia of pigs at short range (<5 m). For large pigs over 40 kg, 12 gauge shotguns may be used with shot sizes of SG or SSG. BB cartridges are suitable for small pigs less than 40 kg. The range should be as short as possible to maximise the impact of the shot and minimise the risk of misdirection. Shooting should only be performed by skilled operators with experience using firearms, and who hold the appropriate licences and accreditation. Firearms users must also comply with relevant legislation requirements for storage and transportation of firearms and ammunition.

The Centre for Invasive Species Solutions manages these documents on behalf of the Environment and Invasives Committee (EIC). The authors of these documents have taken care to validate the accuracy of the information at the time of writing. This information has been prepared with care but it is provided “as is”, without warranty of any kind, to the extent permitted by law.

How to reference this page:

Centre for Invasive Species Solutions, 2014. Trapping of feral pigs. Factsheet. Centre for Invasive Species Solutions. PestSmart website. https://pestsmart.org.au/toolkit-resource/trapping-of-feral-pigs accessed 28-10-2020