ABOVE: Photo: J Oostrom, supplied by the Centre for Invasive Species Solutions
In early December, the final stakeholder forum for 2022 of the National Feral Pig Action Plan addressed the theme of ‘The power of data to inform feral pig management strategies’.
Feral pig management is difficult, expensive and time consuming.
Unfortunately, no single technique can be used effectively to achieve population reduction targets in an area.
At least 70 percent of the feral pig population needs to be removed in a short period of time to keep ahead of their breeding rate and ensure that populations can’t recover quickly.
This is easier said than done if the right combinations of control methods appropriate for the landscape are not being used, are not being applied well, at the right time and management decisions are not backed by good information.
Department of Agriculture and Fisheries Queensland’s Cameron Wilson discussed new learnings of feral pig movement in the landscape, generated from his recent analysis of data collected by GPS collars fitted to feral pigs.
Dr Jack Pascoe from the Conservation Ecology Centre at Cape Otway in Victoria presented on work underway to reduce environmental and cultural impacts caused by feral pigs as part of the Wild Otways Initiative program, funded by the Australian Government.
Techniques including camera traps, environmental DNA monitoring of waterways, GPS collars and FeralScan reporting of sightings by the community are being used in this project to inform management strategies.
Regional information on a real-time basis to know where feral pigs go, what they do and why they move to different locations at different times of the year would be a game-changer to improve outcomes from population reduction programs.
Such knowledge would be extremely useful in setting feral pig management strategies to optimise population reduction and reduce costs and effort of programs.
DAF has been working in collaboration with Darren Marshall from Southern Queensland Landscapes to analyse movement data captured from GPS collars fitted to 59 feral pigs in four sites in Queensland, southern NSW and Torres Strait.
These pigs were collared between 2017 and 2021 for an average of 368 days per pig.
A summary of Cameron’s key messages is provided below.
These points may be useful to consider when updating your feral pig management plans for your property.
Feral pigs move across the landscape and ignore fence lines.
Therefore, a coordinated approach by land managers working together for extended periods of time is needed to reduce both their populations and the many impacts that they cause.
This is what is being advocated by the National Feral Pig Action Plan.
Feral pigs spent 50 percent of their time in only 9 percent of the entire area of their home range.
Targeting control efforts to this smaller core area would save resources, reduce costs and labour required while achieving higher population reductions.
For most land managers, this knowledge is currently limited due to the lack of information but may become increasingly possible over the next five years as technology becomes more affordable.
The average home range of an adult male pig was 13.9sq km and 7.5sq km for females.
This highlights that sounder groups remain in smaller areas close to available water and feed, with males moving through the landscape to service different sows.
Across the four landscapes involved in this study, feral pigs preferred habitat with canopy cover of 21-30 percent.
Overall, the movement data demonstrated that 91 percent of feral pigs preferred habitat with 11-50 percent canopy cover.
For many collared pigs, active avoidance of dense vegetation with a canopy cover of >50 percent was observed.
Open country with 0-10 percent was also avoided.
This debunks commonly held perceptions that feral pigs prefer dense vegetation.
An analysis of highly visited points in the landscape showed that 44 percent were water-related, including dams, rivers, creeks and landscape drainage lines.
It was also found that 50 percent of revisitations to a site were within 150m of a water source, indicating preferred habitat.
Visits to dam-related points on the inlet side only were 93 percent – this may be due to food, shade or preferred habitat for wallowing.
Surveillance monitoring and control tools would be best to locate in these areas.
Of all highly revisited points in woody vegetation, 89 percent were within 150m of the boundary between open and woody vegetation.
While these outcomes do not cover every landscape across Australia, this knowledge provides very useful insights that can be applied by land managers in many other landscapes when designing and conducting feral pig management programs.
When thinking about whether feral pigs may be in your area and where they may be, consider the resources that are present and map them – for water, food and shade.
This includes access to refuse pits, feed troughs and water points for other livestock and grain spillage around silos, as well as to water points.
Manage access to these areas by installing and regularly maintaining feral animal-proof fencing to minimise risks of disease transmission between feral and domestic livestock.
Visits to these areas by feral pigs may occur mainly at night in areas inhabited by humans – while you may never see them, it doesn’t mean they are not there!
The stakeholder forum presentations were recorded and can be accessed via feralpigs.com.au.
Feel free to contact me on firstname.lastname@example.org or call 0423 056 045 to discuss your feral pig management issues or any information presented in this article.