H5 bird flu: BirdLife Australia expert sheds light on brown skua that contracted disease, WA sighting rare
An Australian bird expert has shed light on how an Antarctic brown skua that died after contracting the highly contagious H5 bird flu reached the shores of Western Australia.
On Sunday, June 14, a brown skua was discovered on a beach in Cape Le Grand National Park, about 700 kilometers southeast of Perth.
He tested positive for the disease on Saturday, and Australian Agriculture Minister Julie Collins confirmed it was the first time the virus had been detected on the Australian continent.
A giant bird found nearby was also tested and returned a suspected positive result.
Both birds tested are thought to have migrated to Australia from below Antarctica, where H5 is already having devastating effects on wildlife on Australia’s Heard Island, according to BirdLife Australia.
Analysis of drone surveys conducted on two trips to the island in October 2025 and January 2026 found very high mortality rates in southern elephant seal pups and increased mortality rates in king and gentoo penguins.
The brown skua is a sub-Antarctic migratory species that spends most of its life offshore, and although they occasionally visit southern Australia, it is rare to spot them in Western Australia.
Birdlife Australia seabird project co-ordinator Yuna Kim said these birds were rarely seen off the coast of Western Australia, but they could be drawn ashore when sick or after extreme weather events.
Dr Kim said he was surprised that the infected skua and bird were found alive because they are usually not fit enough to leave their colonies after becoming infected.
“They’ve probably been fighting for so long that they haven’t managed to fly and are swimming in the sea, but are being dragged onto the beach with the current,” he said.
“When it’s a highly pathogenic, dangerous virus, I would probably expect them to be dead by now.”
Dr Kim said the infected birds likely came from Heard Island or elsewhere in the Antarctic region. Their origins can be confirmed through genetic testing, but studies can be difficult due to the large number of inaccessible islands.
“This bird may have contracted the virus somewhere in Antarctica, but that could mean another island may have also been exposed to this virus, but we don’t know,” he said.
“They hang out around fishing grounds and fishing boats. There are thousands of birds looking for food, and the disease can be transmitted from there.”
Dr Kim said the brown skua was on the authorities’ list of birds identified as being at high risk of spreading H5 due to their migratory and scavenger behavior.
The brown skua breeds in the harsh environments of the sub-Antarctic and Antarctic regions, where it is well adapted to the cold and often inhospitable conditions.
They remain almost exclusively in the open ocean to hunt and feed, although they sometimes venture into Australian waters during the non-breeding months (March to October).
Their movements during the breeding season are not as extensive as those of some other migratory species, according to birding app Birda.
When they are spotted closer to the Australian mainland, it is usually during private pelagic birding boat trips offshore, or if they fall ill and become stranded or stranded on remote beaches; Such as the brown skua found in Cape Le Grand National Park.
The south polar skua, a relative of the brown skua, was rarely observed in the Bremer Bay area by photographer Martin Cake in early April 2012.
Birda reported observing skuas exhibiting intelligent behavior, including the ability to recognize individual humans.
In some cases, they have been known to bond with humans who stay in their Antarctic habitats for long periods of time.
According to a document published by Wildlife Health Australia in January, the H5 strain of bird flu originated in Asia, but since 2021 it has spread to Europe, North and South America, and more recently to Antarctica and sub-Antarctic islands.
It has infected more than 560 species of birds abroad and more than 100 species of mammals, including wild marine and terrestrial mammals.
