Gentoo penguins on a remote sub-Antarctic island have become the first birds in an Australian territory to test positive for the highly pathogenic H5N1 avian influenza, federal authorities confirmed Tuesday. The discovery, made on Heard Island, follows earlier detections of the virus in southern elephant seals and fur seals, raising concerns about the broader impact of the outbreak on vulnerable Antarctic wildlife.
Heard Island, an Australian territory approximately 4,000 kilometers southwest of Perth and 1,700 kilometers north of Antarctica, has been experiencing an outbreak of H5N1 since the virus was first suspected in November 2025. Australian Antarctic Program scientists, conducting a second voyage to the island, collected samples that confirmed the presence of the virus in gentoo penguins.
“The gentoo penguins of Heard Island are now the first birds in an Australian territory to test positive for this virus that has devastated wildlife around the world,” said Professor Hugh Possingham, vice-president of BirdLife Australia. “They will certainly not be the last.”
The H5N1 virus has been spreading rapidly across the globe, causing significant mortality in seabirds, wild birds, and poultry. It initially entered the Antarctic region during the 2023-24 season, with initial detections in South Georgia and the Antarctic peninsula. Over the following year, the virus spread to Marion Island and the French sub-Antarctic islands of Kerguelen and Crozet, located approximately 500 kilometers from Heard and McDonald islands.
Dr. Michelle Wille, an expert in avian influenza viruses at the University of Melbourne, described the situation as “catastrophic for wildlife,” noting the virus has already spread thousands of kilometers over the ocean. She cautioned that the virus could potentially spread to other Australian and New Zealand sub-Antarctic islands, such as Macquarie Island, and eventually reach the Australian mainland.
“We are at risk of this virus arriving to Australia, either from this potential southern route, or from a northern route,” Wille said, emphasizing the importance of ongoing surveillance and preparedness efforts.
Federal Agriculture Minister Julie Collins stated that the Australian government takes the threat of bird flu seriously and has invested over $100 million to strengthen preparedness and response capabilities. She acknowledged that continued detections on Heard Island reinforce the demand for continued vigilance.
“Biosecurity is a shared responsibility, and Australia’s success depends on close cooperation between governments, industry, communities and individuals,” Collins said in a statement.
Possingham expressed disappointment with the government’s response to inquiries regarding increased protections for Australian wildlife. “Since the virus was first suspected and subsequently confirmed on Heard Island, we’ve been asking the government highly directly how protections for wildlife are being ramped up to safeguard Australian wildlife from this virus that is very clearly on the move,” he said. “We’re disappointed that those questions largely remain unanswered.”
The federal government maintains that Australia remains free of H5N1, and the recent detections on Heard Island do not substantially increase the risk to the mainland. However, scientists warn that the virus’s ability to spread rapidly and affect multiple species poses a significant threat to the unique and vulnerable bird populations of the region, including the Heard Island cormorant and Heard Island sheathbill, which are found nowhere else on Earth.
