Migratory Seabird Tests Positive for Avian Influenza in Western Australia

A migratory seabird found in southern Western Australia has tested positive for avian influenza with further testing under way to confirm if it is Australia’s first mainland case of the deadly H5N1 strain.

The brown skua, a subantarctic species, was found at Cape Le Grand national park on Sunday and had since died, the WA government said on Friday.

A second bird, a giant petrel, was sick and being tested.

Initial testing at a WA laboratory returned a “suspected positive result for avian influenza”, the agriculture minister, Julie Collins, said.

Samples have been sent to CSIRO’s Australian Centre for Disease Preparedness for confirmation, with results expected on Saturday.

Collins met with state and territory agencies and industry experts on Friday, with further briefings planned for Saturday.

“There is no evidence of any mass mortality at this time. Nor is there any evidence of infection in poultry,” she said.

“If it is confirmed to be the H5 bird flu, this will be sobering, but not unexpected given the spread globally.”

“We certainly expected we couldn’t remain H5 free forever, as the only continent currently that is free of the H5 bird flu.”

She reminded people not to touch sick or dead birds, or other animals, and to report any sighting to the emergency animal disease hotline (1800 675 888) or to birdflu.gov.au.

WA agriculture minister Jackie Jarvis said the brown skua bird was found unwell on Cape Le Grand beach on 14 June, and subsequently died. “Appropriate action, including isolating the bird, was taken and samples collected for testing.”

The second bird, a sick giant petrel was also found in the same area, she said. “This has also been tested, and we are awaiting results.”

“In recent years, H5 bird flu has spread fast around the world, causing severe disease and high death rates in poultry, wild birds, and affected mammals,” Jarvis said.

“If this is a confirmed H5 bird incursion, there will be a rapid and coordinated national response.”

The news comes days after scientists confirmed thousands of southern elephant seal pups on Heard Island and hundreds of adult king penguins in the subantarctic had died from the disease through 2025 and 2026.

Dr Carol Booth, a policy director with the Invasive Species Council, said while test results were necessary to confirm if it was the deadly H5N1 strain, the “detection is deeply concerning given the devastating impacts the virus is having on wildlife around the world”.

“We desperately hope this is not the realisation of our worst dreams. The recently reported mass deaths of elephant seals on Heard Island were a harbinger of the potential catastrophe for Australian wildlife if the virus has made it to mainland Australia.”

“If H5N1 is confirmed, the government’s own risk assessment predicts potentially catastrophic impacts on native birds, while the virus’s increasing ability to infect mammals raises the prospect of severe impacts on marine mammals and other wildlife.”

Booth said it was a “good thing” that Australian governments had spent the past two years preparing for the arrival of the deadly strain but a mainland detection would be “a critical test of Australia’s preparedness and response systems”.

“Even if this is a false alarm, it warns against any complacency. Australia needs to be ready at any time with clear response plans. It also highlights the urgency of mitigating other threats to potentially susceptible wildlife,” she said.

Birdlife Australia’s chief executive Kate Millar said the development was “highly concerning”.

Millar said the organisation’s scientists and grassroots members had worked with governments to increase monitoring for suspected cases and train people in how to report and respond appropriately.

Birdlife had also helped model possible entry points for the deadly H5N1 strain and how it might spread, she said. That included the risk of the disease spreading from entry points on the subantartic islands or via entry points in the north of Australia from birds migrating from Asia.

She called on the government to “ensure that the expertise of an organisation like BirdLife Australia is part of any ongoing discussions that are happening around this suspected case in WA”.

Millar said the organisation was “very concerned” about the effects of the deadly strain on Heard Island, about 4,000km south-west of Perth, which has caused mass mortality of southern elephant seal pups.

Several hundred dead adult king penguins were also observed, on scientific voyages to the island in 2025 and 2026.