Register      Login
Australian Journal of Zoology Australian Journal of Zoology Society
Evolutionary, molecular and comparative zoology
RESEARCH ARTICLE

How many feral pigs in Australia? An update

Jim Hone https://orcid.org/0000-0002-8104-8852
+ Author Affiliations
- Author Affiliations

Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Email: jim.hone@canberra.edu.au

Australian Journal of Zoology 67(4) 215-220 https://doi.org/10.1071/ZO20077
Submitted: 24 August 2020  Accepted: 8 October 2020   Published: 4 November 2020

Abstract

The abundance of feral pigs in Australia has been estimated previously and been a topic of some debate. This study aims to update a previous estimate of abundance (13.5 million, 95% CI: 3.5 million to 23.5 million) of feral pigs in Australia. Abundance estimates for the 1970s, 1980s, 1990s, 2000s and 2010s were collated from published literature. Mean abundances in the middle decades were estimated using the ratio method. The average abundance of feral pigs varied from 4.4 million (95% CI: 2.4 million to 6.3 million) in the 1980s, to 3.0 million (95% CI: 2.3 million to 3.7 million) in the 1990s, to 3.2 million (95% CI: 2.4 million to 4.0 million) in the 2000s. Mean density across all 142 studies was 1.03 pigs km–2. The average abundance of feral pigs in Australia during the 1980s to 2000s was much lower and more precise than estimated previously, so scientists and managers should update their use of abundance estimates. Density estimates are above, and below, estimates of threshold host densities for infectious exotic disease establishment.

Keywords: abundance, bias, feral pig, precision, Sus scrofa, threshold host density.


References

Adams, P. J., Fontaine, J. B., Huston, R. M., and Fleming, P. A. (2019). Quantifying efficacy of feral pig (Sus scrofa) population management. Wildlife Research 46, 587–598.
Quantifying efficacy of feral pig (Sus scrofa) population management.Crossref | GoogleScholarGoogle Scholar |

Caley, P. (1989). Feral pigs in the Douglas–Daly area of the Northern Territory. Report to the Conservation Commission of the Northern Territory, Darwin.

Caley, P. (1993). Population dynamics of feral pigs (Sus scrofa) in a tropical riverine habitat complex. Wildlife Research 20, 625–636.
Population dynamics of feral pigs (Sus scrofa) in a tropical riverine habitat complex.Crossref | GoogleScholarGoogle Scholar |

Caughley, G. (1977). Sampling in aerial surveys. Journal of Wildlife Management 41, 605–615.
Sampling in aerial surveys.Crossref | GoogleScholarGoogle Scholar |

Choquenot, D. (1995). Assessing visibility bias associated with helicopter counts of feral pigs in Australia’s semi-arid rangelands. Wildlife Research 22, 569–578.
Assessing visibility bias associated with helicopter counts of feral pigs in Australia’s semi-arid rangelands.Crossref | GoogleScholarGoogle Scholar |

Choquenot, D., Kay, B., and Lukins, B. (1990). An evaluation of warfarin for the control of feral pigs. Journal of Wildlife Management 54, 353–359.
An evaluation of warfarin for the control of feral pigs.Crossref | GoogleScholarGoogle Scholar |

Choquenot, D., Kilgour, R., and Lukins, B. (1993). An evaluation of feral pig trapping. Wildlife Research 20, 15–22.
An evaluation of feral pig trapping.Crossref | GoogleScholarGoogle Scholar |

Choquenot, D., McIlroy, J., and Korn, T. (1996). ‘Managing Vertebrate Pests. Feral Pigs.’ (Bureau of Resource Sciences: Canberra.)

Choquenot, D., Lukins, B., and Curran, G. (1997). Assessing lamb predation by feral pigs in Australia’s semi-arid rangelands. Journal of Applied Ecology 34, 1445–1454.
Assessing lamb predation by feral pigs in Australia’s semi-arid rangelands.Crossref | GoogleScholarGoogle Scholar |

Corbett, L. (1995). Does dingo predation or buffalo competition regulate feral pig populations in the Australian wet–dry tropics? Wildlife Research 22, 65–74.
Does dingo predation or buffalo competition regulate feral pig populations in the Australian wet–dry tropics?Crossref | GoogleScholarGoogle Scholar |

Cowled, B., and Garner, G. (2008). A review of geospatial and ecological factors affecting disease spread in wild pigs: considerations for foot-and-mouth disease spread. Preventive Veterinary Medicine 87, 197–212.
A review of geospatial and ecological factors affecting disease spread in wild pigs: considerations for foot-and-mouth disease spread.Crossref | GoogleScholarGoogle Scholar | 18508144PubMed |

Cowled, B. D., Garner, M. G., Negus, K., and Ward, M. P. (2012). Controlling disease outbreaks in wildlife using limited culling: modelling classical swine fever incursions in wild pigs in Australia. Veterinary Research 43, 3.
Controlling disease outbreaks in wildlife using limited culling: modelling classical swine fever incursions in wild pigs in Australia.Crossref | GoogleScholarGoogle Scholar | 22243996PubMed |

Dexter, N. (2003). Stochastic models of foot and mouth disease in feral pigs in the Australian semi-arid rangelands. Journal of Applied Ecology 40, 293–306.
Stochastic models of foot and mouth disease in feral pigs in the Australian semi-arid rangelands.Crossref | GoogleScholarGoogle Scholar |

Doran, R. J., and Laffan, S. W. (2005). Simulating the spatial dynamics of foot and mouth disease outbreaks in feral pigs and livestock in Queensland, Australia, using a susceptible–infected–recovered cellular automata model. Preventive Veterinary Medicine 70, 133–152.
Simulating the spatial dynamics of foot and mouth disease outbreaks in feral pigs and livestock in Queensland, Australia, using a susceptible–infected–recovered cellular automata model.Crossref | GoogleScholarGoogle Scholar | 15967247PubMed |

Fleming, P. J. S., Choquenot, D., and Mason, R. J. (2000). Aerial baiting of feral pigs (Sus scrofa) for the control of exotic disease in the semi-arid rangelands of New South Wales. Wildlife Research 27, 531–537.
Aerial baiting of feral pigs (Sus scrofa) for the control of exotic disease in the semi-arid rangelands of New South Wales.Crossref | GoogleScholarGoogle Scholar |

Gentle, M., Pople, A., Scanlan, J. C., and Carter, J. (2019). The dynamics of feral pig (Sus scrofa) populations in response to food supply. Wildlife Research 46, 191–204.
The dynamics of feral pig (Sus scrofa) populations in response to food supply.Crossref | GoogleScholarGoogle Scholar |

Giles, J. R. (1980). The ecology of feral pigs in New South Wales. Ph.D. thesis, University of Sydney.

Hone, J. (1990a). How many feral pigs in Australia? Wildlife Research 17, 571–572.
How many feral pigs in Australia?Crossref | GoogleScholarGoogle Scholar |

Hone, J. (1990b). Predator–prey theory and control of feral pigs, with emphasis on shooting from a helicopter. Wildlife Research 17, 123–130.
Predator–prey theory and control of feral pigs, with emphasis on shooting from a helicopter.Crossref | GoogleScholarGoogle Scholar |

Hone, J. (2012). ‘Applied Population and Community Ecology. The Case of Feral Pigs in Australia.’ (Wiley Blackwell: Oxford.)

Hone, J. (2016). Probably fewer wild pigs than that. New Scientist 230, 53..

Hone, J., and Buckmaster, T. (2014). How many are there? The use and misuse of continental-scale wildlife abundance estimates. Wildlife Research 41, 473–479.
How many are there? The use and misuse of continental-scale wildlife abundance estimates.Crossref | GoogleScholarGoogle Scholar |

Hone, J., Pech, R., and Yip, P. (1992). Estimation of the dynamics and rate of transmission of classical swine fever (hog cholera) in wild pigs. Epidemiology and Infection 108, 377–386.
Estimation of the dynamics and rate of transmission of classical swine fever (hog cholera) in wild pigs.Crossref | GoogleScholarGoogle Scholar | 1582476PubMed |

Legge, S., Murphy, B. P., McGregor, H., Woinarski, J. C. Z., Augusteyn, J., Ballard, G., Baseler, M., Buckmaster, T., Dickman, C. R., Doherty, T., Edwards, G., Eyre, T., Fancourt, B. A., Ferguson, D., Forsyth, D. M., Geary, W. L., Gentle, M., Gillespie, G., Greenwood, L., Hohnen, R., Hume, S., Johnson, C. N., Maxwell, M., McDonald, P. J., Morris, K., Moseby, K., Newsome, T., Nimmo, D., Paltridge, R., Ramsey, D., Read, J., Rendall, A., Rich, M., Ritchie, E., Rowland, J., Short, J., Stokeld, D., Sutherland, D. R., Wayne, A. F., Woodford, L., and Zewe, F. (2017). Enumerating a continental-scale threat: how many feral cats are in Australia? Biological Conservation 206, 293–303.
Enumerating a continental-scale threat: how many feral cats are in Australia?Crossref | GoogleScholarGoogle Scholar |

Lewis, J. S., Fransworth, M. L., Burdett, C. L., Theobald, D. M., Gray, M., and Miller, R. S. (2017). Biotic and abiotic factors predicting global distribution and population density of an invasive large mammal. Scientific Reports 7, 44152.
Biotic and abiotic factors predicting global distribution and population density of an invasive large mammal.Crossref | GoogleScholarGoogle Scholar | 28276519PubMed |

Massei, G., Kindberg, J., Liccope, A., Gacic, D., Sprem, N., Kamler, J., Baubet, E., Hohmann, U., Monaco, A., Ozolins, J., Cellina, S., Podgorski, T., Fonseca, C., Markov, N., Pokorny, B., Rosell, C., and Nahlik, A. (2015). Wild boar populations up, number of hunters down? A review of trends and implications for Europe. Pest Management Science 71, 492–500.
Wild boar populations up, number of hunters down? A review of trends and implications for Europe.Crossref | GoogleScholarGoogle Scholar | 25512181PubMed |

McIlroy, J. C., and Saillard, R. J. (1989). The effects of hunting with dogs on the numbers and movements of feral pigs, Sus scrofa, and the subsequent success of poisoning exercises in Namadgi National Park, A.C.T. Australian Wildlife Research 16, 353–363.
The effects of hunting with dogs on the numbers and movements of feral pigs, Sus scrofa, and the subsequent success of poisoning exercises in Namadgi National Park, A.C.T.Crossref | GoogleScholarGoogle Scholar |

McIlroy, J., Braysher, M., and Saunders, G. (1989). Effectiveness of a warfarin-poisoning campaign against feral pigs, Sus scrofa, in Namadgi National Park, A.C.T. Australian Wildlife Research 16, 195–202.
Effectiveness of a warfarin-poisoning campaign against feral pigs, Sus scrofa, in Namadgi National Park, A.C.T.Crossref | GoogleScholarGoogle Scholar |

Mitchell, J. (1998). The effectiveness of aerial baiting for control of feral pigs (Sus scrofa) in north Queensland. Wildlife Research 25, 297–303.
The effectiveness of aerial baiting for control of feral pigs (Sus scrofa) in north Queensland.Crossref | GoogleScholarGoogle Scholar |

Pech, R. P., and Hone, J. (1988). A model of the dynamics and control of an outbreak of foot and mouth disease in feral pigs in Australia. Journal of Applied Ecology 25, 63–77.
A model of the dynamics and control of an outbreak of foot and mouth disease in feral pigs in Australia.Crossref | GoogleScholarGoogle Scholar |

Pech, R. P., and McIlroy, J. C. (1990). A model of the velocity of advance of foot and mouth disease in feral pigs. Journal of Applied Ecology 27, 635–650.
A model of the velocity of advance of foot and mouth disease in feral pigs.Crossref | GoogleScholarGoogle Scholar |

Saunders, G. (1988). The ecology and management of feral pigs in New South Wales. M.Sc. thesis, Macquarie University, Sydney.

Saunders, G., and Bryant, H. (1988). The evaluation of a feral pig eradication program during a simulated exotic disease outbreak. Australian Wildlife Research 15, 73–81.
The evaluation of a feral pig eradication program during a simulated exotic disease outbreak.Crossref | GoogleScholarGoogle Scholar |

Saunders, G., and Kay, B. (1991). Movements of feral pigs (Sus scrofa) at Sunny Corner, New South Wales. Wildlife Research 18, 49–61.
Movements of feral pigs (Sus scrofa) at Sunny Corner, New South Wales.Crossref | GoogleScholarGoogle Scholar |

Saunders, G., Kay, B., and Parker, B. (1990). Evaluation of a warfarin poisoning programme for feral pigs (Sus scrofa). Wildlife Research 17, 525–533.
Evaluation of a warfarin poisoning programme for feral pigs (Sus scrofa).Crossref | GoogleScholarGoogle Scholar |

Saunders, G., Kay, B., and Nichol, H. (1993). Factors affecting bait uptake and trapping success for feral pigs (Sus scrofa) in Kosciusko National Park. Wildlife Research 20, 653–665.
Factors affecting bait uptake and trapping success for feral pigs (Sus scrofa) in Kosciusko National Park.Crossref | GoogleScholarGoogle Scholar |

Statham, M., and Middleton, M. (1987). Feral pigs on Flinders Island. Papers and Proceedings of the Royal Society of Tasmania 121, 121–124.
Feral pigs on Flinders Island.Crossref | GoogleScholarGoogle Scholar |

Strahan, R. (1995). ‘The Mammals of Australia.’ 2nd edn. (Reed: Sydney.)

Twigg, L., Lowe, T., Martin, G., and Everett, M. (2005). Feral pigs in north-western Australia: basic biology, bait consumption, and the efficacy of 1080 baits. Wildlife Research 32, 281–296.
Feral pigs in north-western Australia: basic biology, bait consumption, and the efficacy of 1080 baits.Crossref | GoogleScholarGoogle Scholar |

Twigg, L., Lowe, T., Everett, M., and Martin, G. (2006). Feral pigs in north-western Australia: population recovery after 1080 baiting and further control. Wildlife Research 33, 417–425.
Feral pigs in north-western Australia: population recovery after 1080 baiting and further control.Crossref | GoogleScholarGoogle Scholar |

Van Dyck, S., and Strahan, R. (2008). ‘The Mammals of Australia.’ 3rd edn. (New Holland: Sydney.)

West, P. (2008). ‘Assessing Invasive Animals in Australia.’ (National Land and Water Resources Audit & Invasive Animals Cooperative Research Centre: Canberra.)

Wilson, G., Hill, G. J. E., and Barnes, A. (1987). An aerial survey of feral pigs and emus in south-eastern Queensland. Australian Wildlife Research 14, 515–520.
An aerial survey of feral pigs and emus in south-eastern Queensland.Crossref | GoogleScholarGoogle Scholar |