Gentoo penguins on Heard Island, a remote Australian territory in the sub-Antarctic, have tested positive for the H5N1 avian influenza virus, marking the first confirmed cases of the disease in birds within Australian territory. The discovery, announced by the Australian Antarctic Program, follows earlier confirmation of the virus in southern elephant seals on the island in November 2025.
Australian Antarctic Program scientists detected the virus in gentoo penguins and fur seals during a second voyage to Heard Island to monitor the outbreak. Heard Island, approximately 4,000 kilometers southwest of Perth and 1,700 kilometers north of Antarctica, serves as a crucial breeding ground for a variety of wildlife.
The H5N1 strain, which has caused widespread mortality among seabirds, wild birds, and poultry globally, represents a “very concerning development,” according to Professor Hugh Possingham, vice-president of BirdLife Australia. “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,” Possingham stated. “They will certainly not be the last.”
Preliminary test results confirming the expanded presence of the H5 avian influenza were also released by the Hon Julie Collins MP, Minister for Agriculture, Fisheries and Forestry.
The spread of the virus to gentoo penguins raises concerns about the potential impact on other vulnerable bird species endemic to Heard Island, including the Heard Island cormorant and Heard Island sheathbill. These species, found nowhere else on Earth, could face significant threats from the highly pathogenic strain.
Scientists are continuing to monitor the situation on Heard Island to assess the full extent of the outbreak and its potential consequences for the region’s unique biodiversity. The remote location and isolated nature of the island’s wildlife populations may render them particularly susceptible to the virus due to a lack of prior exposure.
