In a huge win for Australian wildlife, authorities say they have effectively eliminated feral pigs from the nation’s third-biggest island, where they previously ran amok in plague proportions.
Once over 5,000 of the introduced pests, known as one of the country’s most significant and invasive threats, roamed Kangaroo Island in South Australia — there are now thought to be virtually none left.
During the horror 2019-2020 Black Summer bushfires, which tore across more than half of the island, destroying countless native animals and protected plant species, it’s believed feral population pig numbers were also reduced by an astonishing 90 per cent —an unexpected but welcomed outcome.
While it’s “not the nicest thing to think about”, the fact that over 4,000 pigs perished in the fires meant that authorities finally had a leg-up on the situation. They were able to quickly spring into action with a multi-million-dollar eradication program — which commenced in July — to wipe out the remaining population before the animals, among the most prolific breeders of land mammals, could bounce back.
The pigs were attacked on all fronts with a “range” of methods including a clever pig-specific bait device that affects pigs in a way similar to carbon monoxide poisoning, killing them quickly. These boxes, cannot be opened by any other animal, Peter Hamnett of Flinders University’s University’s Global Ecology Lab told Yahoo News Australia.
In Australia, recent estimates suggest feral pig numbers may have skyrocketed to as high as 50 million, a jaw-dropping figure that experts warn is vastly at odds with official government statistics, which suggest populations are instead between three to 13 million.
Hamnett, the lead author of a new paper on optimal strategies for culling feral pigs. He explained to Yahoo News Australia what this incredible feat means for pig eradication across the rest of the country.
A range of methods were used to eliminate remaining Kangaroo Island feral pig populations, including these pig-specific traps. Source: PIRSA
What can we learn from Kangaroo Island’s success in eliminating feral pigs?
Currently, feral pigs occupy about 40 per cent of the mainland and offshore islands.
Hamnett said while full eradication on Kangaroo Island is well and truly in sight, surveillance efforts will take place until 2026 to ensure none are missed. He said “one of the main lessons” learned from the program is the importance of speed in hitting populations “hard and early”.
“Pigs have a really high reproductive rate, they’re extremely succumbed, they have large litters, and they’re able to repopulate really quickly,” he said. “So it’s critical that land managers aim to reduce these populations rapidly.
“Many eradication programs have failed because the level of effort required to reduce populations isn’t achieved. We need to make sure that when people seek to achieve these outcomes, they hit the populations hard and early, and make sure that the reductions are significant enough to drive populations down.”
Authorities aim to have fully eliminated feral pigs from Kangaroo Island by 2026. Source: PIRSA
Hamnett said while bushfires are responsible for initially wiping out large numbers of pigs, the eradication program that was rolled out after swiftly managed those remaining.
He said crews used “a range of control methods” in eradication efforts, the “most effective” being thermal assisted aerial culling, which involves using aircraft equipped with thermal imaging technology to identify and target animals from the air during night-time operations.
He said from July, through to June 2026, a surveillance program will use a range of methods to confirm pigs have in fact been eradicated.
“We’re hoping that there’s none left, but we have to be guarded in or cautious in that, and take the time to do the surveillance before we can finally confirm or make that statement with a high level of confidence,” he said.
Feral pigs destroy natural landscapes, prey on native wildlife, and breed extremely quickly. Source: South Australian Government
What makes Kangaroo Island so unique?
Feral pigs are direct predators of local wildlife in the region, including endangered species such as the Kangaroo Island dunnart and the echidna. Their activity also threatens ecosystems by destroying vegetation and compacting soil.
Kangaroo Island spans approximately 4,405 square kilometres and features 509 kilometres of unspoiled coastline. Known for its remarkable conservation efforts, over one-third of the island is designated as protected areas, including national and conservation parks.
This pristine environment is home to unique wildlife, including kangaroos, koalas, echidnas, and the endangered glossy black cockatoo, thriving in the absence of invasive species like foxes and rabbits.
The $7 million eradication program is funded by both the state and Commonwealth governments in collaboration with the Department of Primary Industries and Regions South Australia (PIRSA) and investors. The program managed to kill 900 pigs in total, after some 4,500 were wiped out in fires.
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