The heartbreaking moment when scientists discovered bird flu signs in Australian territory

When Australian scientists investigated whether a deadly wave of bird flu that has decimated wildlife globally had reached the sub-Antarctic Australian territory of Heard Island, they were initially reassured.

Wildlife ecologist Dr Julie McInnes, one of the team on board the ship RSV Nuyina, said the expedition to the remote island started with drone surveys, which covered a large area of coastline and showed healthy populations of seabirds, king penguins and both elephant seals and Antarctic fur seals.

The early ground surveys were also promising. Then the team visited a beach on the southern end of the island used as a breeding colony for elephant seals and made a devastating discovery: the shoreline was littered with dead pups and a few dead adults. The females usually feed their pups for three weeks, but most were absent, possibly having returned to sea after losing their babies.

“This is the peak breeding time for seals on the island and for elephant seals,” McInnes said. “The females come ashore, they give birth to the pups, and there are males defending their harems, so the beach is very full. Unfortunately, when we turned up at this area, we did find a number of mortalities across the site.

“It’s quite difficult for the teams on the ground when they see the species that they love impacted this way, but the team has been incredible, very professional, very good at actually getting the tasks done under very trying circumstances.”

The symptoms were consistent with the H5N1 avian influenza virus, which has spread to every continent except Australia and has been detected less than 450 kilometres away on the French sub-Antarctic islands of Kerguelen and Crozet.

The scientists wore personal protective equipment to take swabs from the dead animals and securely package the samples for transport back to Australia. The estimated wildlife deaths will be calculated based on the surveys over coming weeks on the return voyage, while the H5N1 outbreak will be confirmed after testing by the CSIRO Australian Centre for Disease Preparedness next month.

Dr Michelle Wille, at the University of Melbourne’s WHO Collaborating Centre for Reference and Research on Influenza, said this flu strain had killed huge numbers of animals, affecting more than 400 species of birds and probably 60 species of mammals globally.

For example, in South America since late 2022, H5N1 bird flu has killed more than 30,000 sea lions, 18,000 pups in one breeding colony of southern elephant seal pups alone, and at least 650,000 native birds, including 40 per cent of Peru’s pelicans. At least 40 per cent of all northern gannets that exist on the planet were wiped out in 2022, Wille said.

“It’s been catastrophic everywhere, and somehow we have managed to escape it thus far,” she said. “I think it will arrive [in Australia] at some point. However, the exact time and the exact mechanism of arrival is uncertain.”

This masthead has previously reported that a H5N1 outbreak in mainland Australia could wipe out the 12,000 Australian sea lions left on the planet and send black swans extinct.

The Heard and McDonald Islands external Australian territory is 4000 kilometres southwest of Perth and 1700 kilometres north of Antarctica in the Southern Ocean, and part of a marine park that quadrupled in size last year. The uninhabited islands made headlines earlier this year when US President Donald Trump slapped a 10 per cent tariff on their non-existent exports.

The mission, which left Australia in September, will also visit McDonald Island, but the scientists will confine themselves to drone surveys because of the sensitive ecology. McInnes said there were also plans to return over summer, and the scientists would be bracing themselves for signs of the virus spreading to more species.

Wille said one of the ways the virus spread was through water, which made marine and aquatic animals particularly vulnerable, and that the disease attacked the nervous system.

“We’re seeing lots of animals with signs of neurological disease: they can’t stand up, they fall over, and birds are often twisted in this really strange position called torticollis,” Wille said. “When they die, we also see respiratory signs in animals, so they struggle to breathe. On ... Kerguelen and Crozet ... they’ve reported seeing southern elephant seals with eyes that look like they’re wearing goggles, so we’re seeing lots of infection in the eyes.”

The virus reached Antarctica in the 2023-24 season, Wille said, with detections on the sub-Antarctic island of South Georgia, the Antarctic Peninsula and South Shetland Islands. It was found again in the 2024-25 summer in the same locations before it spread to Kerguelen and Crozet.

Wille said king penguins in the sub-Antarctic islands were heavily affected, as were African penguins, but many of the charismatic species such as emperor penguins were so far mostly unscathed for unknown reasons.

The Australian government is investing more than $100 million into strengthening bird flu preparedness, including surveillance of wild birds, and is encouraging members of the public to report any wildlife showing symptoms.

Other countries have vaccinated wild birds – New Zealand has vaccinated critically endangered kakapos and four other endangered bird species, while the United States has successfully vaccinated and released condors.

A spokesperson for the Department of Agriculture said the Australian government had procured H5N1 avian influenza vaccine and was considering vaccination of priority threatened and native bird species in captivity, but was still determining the dosage and studying the immune response in birds of different sizes. The department ruled out broadscale vaccination of wild birds as not feasible.

Wille said there had been no cases yet of human-to-human transmission, but humans had caught it from wildlife and farm animals.

Invasive Species Council policy director Dr Carol Booth said Australia needed to prepare not just for the “looming H5N1 catastrophe”, but to update federal environmental laws to ensure Australia would be prepared for similar threats in future.

“This outbreak warning from Heard Island reinforces the need for EPBC [Environment Protection and Biodiversity Conservation] Act reforms to give governments the legal tools, funding and co-ordination to prevent and manage major threats to Australia’s wildlife – not just streamline development approvals,” Booth said.

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