Why did it take so long? Asia has lived with H5N1 since the 1990s, and the virus reached Antarctica in 2024. Yet Australia stayed clear until a brown skua turned up sick on the south coast of Western Australia in June 2026.
The bird was found at Cape Le Grand, a park close to Esperance and roughly 700 kilometres south-east of Perth. It died, and tests confirmed H5N1 of clade 2.3.4.4b. Agriculture minister Julie Collins announced the result at a Saturday press conference, June 20, and a sick southern giant petrel from the same spot also looked infected on preliminary testing, with samples going to the CSIRO for confirmation. Before that week, no other continent had stayed free of the strain. Collins admitted that “we all knew that we couldn’t be bird [flu]-free forever.”
The missing ducks
The explanation researchers offer in The Conversation is a matter of travel routes. In the northern hemisphere, freshwater dabbling ducks carry the virus. They show very limited signs of disease and keep migrating while infected, which lets them spread it over long distances. No duck species regularly flies between Asia and Australia, and none migrates through Antarctica either.
So the virus took another road. It reached Antarctica in the summer of 2023-24 and then travelled thousands of kilometres across the subantarctic over 2024-25, apparently on gulls, skuas and giant petrels. Those birds breed in Antarctic waters and roam the Southern Ocean in winter and sometimes range as far as three other oceans. Skuas and petrels are seabirds, not freshwater birds, which is why some biologists hope the virus may struggle to move inland.
It had already announced itself on Australian territory. Australia’s remote subantarctic territories had logged the virus the previous October, on Heard Island and the McDonald group, and about 13,000 baby southern elephant seals on Heard Island are projected to have died over the 2025-26 summer, with bird flu the most likely cause.
What officials said
Prime minister Anthony Albanese called the arrival “concerning” and said Canberra had put $113m into preparations. “What we’re about is making sure, firstly, that we do whatever we can to restrict the spread,” he said. Collins said officials had seen no mass deaths and no infected poultry. BirdLife Australia’s chief executive, Kate Millar, put the stakes bluntly: “This could be the beginning of a long fight to protect birds and wildlife in Australia.”
The worry, according to the researchers, is scavenging. If sick birds are eaten by native birds and mammals, the virus could pass to ducks, and from there the outlook gets far worse.
By August the virus had moved. On August 13, Tasmania confirmed its first case, another brown skua, found dead at Burgess Cove on Rocky Cape on the state’s north-west coast. ABC News reported that the virus had by then touched wildlife in five other Australian states. Tasmania’s primary industries minister, Gavin Pearce, said it was not an outbreak and that commercial poultry had tested clear. Department secretary Jason Jacobi called the arrival “inevitable”.
Sources
- Anthony Albanese says Australia's first mainland case of deadly H5N1 bird flu 'concerning' (The Guardian)
- The first case of H5N1 bird flu in Australia has been confirmed. What does this mean? (The Conversation)
- Tasmania confirms first case of deadly bird flu strain H5N1 (ABC News)
