Environmental issues

Pests and weeds

Feral pigs - fact sheet

History

Feral pigs originated from domestic stock brought to Australia by the early European settlers. By the 1880s feral pig populations were fully established in NSW and they can now be found across about 38 per cent of the continent.

As a result, by August 2004, 'predation, habitat degradation, competition and disease transmission by feral pigs' had been listed as a key threatening process by both the federal and NSW governments.

Distribution in NSW today

Medium-to-high densities of feral pigs are most prevalent in western and northern NSW. They prefer wetlands, floodplains and watercourses. About 30 million hectares in NSW is free of feral pigs with around 10 per cent of this area in national parks.

This means that NSW national parks have relatively more areas free from this pest animal than other land tenures. In fact, the NSW National Parks and Wildlife Service (NPWS), now part of the Department of Environment and Conservation, has over 600,000 hectares more pig-free land than would be expected for the proportion of land it manages (about 8 per cent of the state).

Impact on the environment and agriculture

Feral pigs cause severe environmental degradation by:

  • feeding selectively on plant communities;
  • creating drainage channels in swamps;
  • eroding soil and fouling watering points with their wallowing;
  • eating frogs, reptiles, birds and small mammals;
  • spreading weeds and possibly disease.

Damage by feral pigs is estimated to cost Australian agriculture over $100 million a year. Feral pigs can kill and eat young lambs, compete with livestock for pasture and drought feed, and damage fences and waterholes. They are also a major potential host of a number of exotic diseases such as foot-and-mouth disease.

Management by NPWS

NPWS has control programs for all parks and reserves where feral pigs pose a significant problem. Many of these are in conjunction with local landholders and other government or non-government agencies such as rural lands protection boards (RLPBs).

NPWS also directs considerable resources to tackling illegal pig hunting, which disrupts pig control programs and often allows dogs to escape into parks. Illegal hunters may also release pigs and vandalise or steal NPWS traps.

Control techniques

Aerial shooting of feral pigs is most commonly used by NPWS because it is more efficient than shooting from the ground. However ground shooting is used where trees obscure vision from the air.

Pigs fitted with radio collars are sometimes used to guide shooters to the location of other feral pigs, a control method known as the 'Judas pig' technique. Trapping and 1080 baiting are also used in some areas.

Some NPWS feral pig control programs

Northern Plains

NPWS has run a successful feral pig control program in the Macquarie Marshes since 1980. Between January 2004 and May 2005, more than 1350 feral pigs were removed from Macquarie Marshes Nature Reserve. In 2004, NPWS removed over 700 feral pigs from Narran Lakes Nature Reserve, while between February and May 2005, it culled around 150 feral pigs from the newly acquired Budelah Nature Reserve.

NPWS removed more than 1200 pigs from Planchonella Nature Reserve and surrounding properties near Warialda in 2001. Two years later, feral pig numbers were at an all-time low due to DEC programs. Another 100 pigs a year were removed between 2004 and 2005.

Northern Tablelands

In 2004, 92 feral pigs were removed from national parks, nature reserves and adjoining properties in the Armidale-Walcha area. The program has been expanded to include new reserves, as well as a number of private properties and state forests. In 2004, over 100 feral pigs were culled in the Glen Innes area and more than 85 found and destroyed in Warra and Guy Fawkes River national parks using the 'Judas pig' technique.

Southern NSW

As part of the Alps Memorandum of Understanding, NPWS and the ACT Parks and Conservation Service have implemented a cooperative cross-border pig-baiting program that greatly reduced pig numbers. In South East Forest National Park, the Bombala RLPB has been contracted to assist NPWS to trap pigs. More than 300 pigs were removed from this area between 2002 and 2005.

Blue Mountains

In 2004, more than 500 pigs were destroyed in the southern Blue Mountains area, which includes wilderness areas such as Kanangra-Boyd and Blue Mountains national parks, Yerranderie State Conservation Area and the proposed Murruin wilderness area.

NPWS, together with Sydney Catchment Authority and local RLPBs, have developed a feral pig management strategy for the southern Blue Mountains. This strategy covers 300,000 hectares and is essential for the long-term protection of the Blue Mountains, Nattai and Kanangra-Boyd park systems, which immediately surround Lake Burragorang, the source of Sydney's drinking water.

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Page last updated: 26 February 2011