What does it look like?
Feral pigs are smaller and more muscular than domestic pigs. They are usually black but they can be ginger, sandy brown, white, grey or combinations of these colours. Their tusks are triangular in cross-section, approximately 150mm long and extend out from the lower jaw and curve upwards, outward and backwards.
Feral pigs occur in both native forest and in exotic plantations, and are well established throughout New Zealand.
Why is it a problem?
Feral pigs eat a wide variety of food including grasses, roots, seeds and other plant material as well as carrion, invertebrates (e.g. snails) and ground-nesting birds. They damage forests by uprooting trees and saplings and eating native plants and invertebrates. They also eat pasture and crops and are known to be carriers of bovine tuberculosis and leptospirosis.
Feral pigs breed throughout the year. Each litter comprises 6-10 piglets but only 3-6 are likely to survive. Newborn piglets stay within or near the nest for first 2-3 weeks, wean at 2-4 months and stay with the sow until the next litter is due.
How do you know if you have feral pigs?
The most obvious sign of feral pigs is the animals themselves. Feral pigs have large shoulders, small hindquarters and long straight tails. They are often black in colour, but can be grey, brown, ginger or white.
A common sign of feral pigs is their digging or ‘rooting’ of topsoil. Pigs dig up the ground with their snouts looking for roots, worms and grubs. Pig rooting can cause extensive damage in a short space of time. This digging can be aged by turning over the turfs; if the grass is still green and fresh the activity is relatively recent.
Other sign of pigs includes turned over cowpats, broken rotten logs and wallowing in wet areas with mud and scratch marks on the surrounding trees. Their droppings are relatively large oval pellets that are all joined together. Pig footprints have a round, cloven hoof, sometimes with a visible dew-claw.
Hunting with trained pig hunting dogs and stalking and shooting are the traditional methods of control, and are effective if undertaken correctly. These methods are only suitable in some areas.
Shooting can be restricted by the proximity of neighbours or the place where the pigs are living. There are similar restraints when hunting with dogs.
GW has live-capture pig traps which can be loaned out in specific situations. Where other control options are not available, GW will loan a trap to manage problem feral pigs on private land.
If the trap is borrowed, the person is responsible for the welfare of any captured pigs, including their humane disposal by shooting. The individual must have legal access to a large calibre firearm, and the trap set in a place where it is appropriate to destroy the pig.
Live capture cage trap
The live capture cage trap catches feral pigs behind a swinging one-way door. It is baited with fermented barley to attract the pigs into the trap. It must be placed in a location regularly visited by pigs, and pre-fed before the trap is set.
Setting the cage trap
A flat, clear location is needed to set the trap. Vehicle access is necessary to transport the trap and fermented barley bait. The trap must be securely fastened to the ground by at least four waratah standards, which the trap is then wired to. The site must be flat to ensure that the swing door will close correctly.
Once the trap is in place it should be pre-fed with barley, which can be bought from a farm supply store. Put the barley in a bin or bucket, mix with water, put a lid on it and leave in the sun. Add more water as it is soaked up by the barley. When the barley ferments it emits a strong smell, which is very attractive to pigs. Wire the door of the trap open and lay piles of barley around and in the back of the trap.
If the trap is set immediately it may discourage pigs from entering through the small gap. They need to be regularly entering and feeding from the trap before it is set. This can be a lengthy process, and although pigs are present in an area they may be reluctant to enter the trap. It is important that all hunting with dogs and rifles cease while the trap is in use. Successful trapping requires regular visits from undisturbed pigs.
Once the pigs are regularly entering the trap, it can be set by propping the swinging door open at 45 degrees with a short stick. When a pig pushes under the door it will knock the stick out of the way and the door will close behind it. The pig in the trap cannot push its way out, but more pigs on the outside can push through the one-way door.
By law the trap must be checked within 12 hours of daylight on every day that it is set.
Any feral pigs caught in the trap must be destroyed by shooting with a head or vitals shot. The diagram below shows the correct places to shoot a pig, with a minimum calibre of .223. Do not enter the trap and attempt to capture the pig by hand as even a small pig can inflict a dangerous bite.
It is an offence to capture and release feral pigs. All pigs captured must be destroyed.