Since bird flu first reached Australia’s mainland in June 2026, the virus has spread rapidly. Cases have been confirmed across most of the mainland states and territories and Tasmania. The virus continues to spread to an ever-increasing list of species, from seabirds and shorebirds to marine mammals such as seals, sea lions, and dolphins.
The latest case numbers can be found at the federal government’s webpage here
On Australia’s remote Heard Island, bird flu caused a mass mortality of southern elephant seals over the 2025/26 summer. Researchers estimate over 13,000 pups were lost, with 97% of pups recorded dead in the worst-hit harem (social and mating group).
Delays in the virus reaching Australia have provided us with valuable time to prepare and protect our wildlife, but now we must do more to confront this existential threat to our unique wildlife.
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What is Bird Flu?
Bird flu, or avian influenza, is a type of viral infection that affects birds, including domestic poultry and wild birds.
This highly infectious virus can cause a range of symptoms, from mild respiratory problems, fever and decreased egg production to sudden death.
It is spread through direct contact with infected birds, contaminated food and water, and airborne transmission.
What is the H5N1 Strain?
The strain that is currently sweeping around the globe is called H5N1, also known as H5 High Pathogenicity Avian Influenza (HPAI).
The H5N1/HPAI strain is the most highly contagious and deadly version of the bird flu virus, particularly to vulnerable wildlife, including some mammals.
Three separate strains of bird flu – H7N3, H7N9 and H7N8 – circulate within bird populations and have previously already been detected in Australian poultry farms.
What is the Risk to Marine Wildlife?
Bird flu can have devastating impacts on marine wildlife, including seabirds, shorebirds and marine mammals like pinnipeds (seals and sea lions) and cetaceans (whales and dolphins), potentially leading to significant population declines or even localised extinctions.
The deadly H5N1 strain can also be transmitted between mammals, as shown by the ‘unprecedented’ mass deaths of elephant seals and sea lions in South America. The virus reached South America in 2022 and spread from north to south within six months, killing an estimated 30,000 sea lion pups. However, mammal-to-mammal transmission has not yet been documented in Australia.
H5N1 has now been detected in pinnipeds on Australia’s mainland. Cases have been confirmed in Australian sea lions, including at key colonies such as Kangaroo Island and The Pages in South Australia, and in long-nosed fur seals and Australian fur seals. Sea lions and fur seals breed in dense groups, meaning the disease could spread quickly once it takes hold. Australia’s pinnipeds are already under pressure from commercial fishing, pollution, habitat destruction and climate change. Mortalities from bird flu would put further pressure on these species, with potentially devastating consequences for colonies that are already depleted.
Australia is home to wildlife found nowhere else on Earth, and some of these species are already in danger of extinction, such as the little penguin and shy albatross. The H5N1 bird flu could have a devastating impact on our unique wildlife, including a real extinction risk for the already endangered Australian sea lion, with a remaining population of about 12,000 along WA and South Australian coasts.
The Australian sea lion, Subantarctic fur seal, blue whale and the southern right whale are among those identified as high risk marine mammals based on their conservation listings. Antarctic fur seal, New Zealand fur seal, Australian fur seal, leopard seal, Weddell seal, Ross seal, and New Zealand sea lion are all identified as highly susceptible in the government’s recent risk assessment report, accessed here.
What Should be Done to Protect Australian Wildlife from Bird Flu?
Collaboration is crucial: state and federal government agencies, conservation organisations and the community must work together to protect Australia’s precious marine wildlife.
Unfortunately, this is no longer a question of prevention. Now that the virus has reached Australia, it is here to stay. AMCS is working with an alliance of environmental organisations to press for immediate, coordinated national action to protect remaining populations. We are calling for the federal government to commit to a wildlife resilience fund of at least $200 million over the next two years.
The experience worldwide demonstrates the potential for this virus to be catastrophic for Australia’s unique wildlife and threatened species. Investing in boosting the resilience of our threatened species by protecting and restoring their habitat, and reducing pressures on their populations is now essential to ensure their future.
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Could vaccination help?
Vaccination can’t stop bird flu spreading through wild populations, but targeted vaccination for certain species and locations could prevent a local extinction. Australia has a policy allowing emergency vaccination of rare and protected bird species, but a vaccine designed specifically for marine mammals is not yet available. Experts are calling for authorities to identify priority seal and sea lion colonies now, and trial candidate vaccines, rather than waiting until mass deaths are already underway. AMCS supports this call as part of a properly funded national resilience plan.
What to do:
If you find a sick or dead bird or other wildlife that you suspect could have bird flu (H5N1), remember to:
AVOID contact with sick or dead wildlife and their environment. Do not touch, move or approach the bird, and do not allow pets to touch or eat sick or dead wildlife.
RECORD what you see, the location the animal was found, and take photos or video (if possible) without approaching the bird / animal.
REPORT any unusual illness or death in wild birds and other wildlife immediately via the Emergency Animal Disease Hotline on 1800 675 888
Infected live birds may show a wide range of signs if they are sick, including:
- lack of coordination, tremors, swimming in circles
- twisted necks or other unusual posture
- inability to stand or fly
- diarrhoea
- difficulty breathing, coughing or sneezing
- swelling around the head, neck and eyes
- cloudiness or change in colour of the eyes.
Want to learn more?
Listen to the webinar hosted by the Biodiversity Council and find further resources here.