‘Devastating’: Western Australia fears black swan moment as bird flu threatens iconic species | Western Australia

When black swans start dying, Western Australians will know that bird flu has really arrived.

Birds are an “indicator species” because once infected with the H5N1 virus they are more likely to die than survive, according to University of Queensland virologist Kirsty Short.

“If bird flu gets to a place where there are black swans… then I think we will see swan mortality and, if there are significant numbers of swans, significant mortality.”

Now, the bird that has come to define the West faces devastating consequences.

Unlike many birds, black swans lack a key immune protein involved in recognizing viral infections, a difference that can leave them vulnerable to a deadly inflammatory response.

The species has been classified as being at “very high risk” of becoming infected with the virus, according to a Commonwealth national risk assessment.

Experts do not yet know how black swans will respond to living with a virus that, once established, is expected to circulate and evolve in wild bird populations.

‘Potential’ to lose entire populations

Black swans live in both coastal and inland freshwater areas and can form large colonies when they breed. One infected bird could cause an entire colony to become extinct, says ornithologist Floyd Holmes of Phoenix Environmental Sciences.

“It’s not likely to wipe out all the swans, but for any local group of swans, particularly in the southwest, that congregate and breed in one place, there’s definitely a chance of losing that entire population at once,” Holmes says.

“It would be quite devastating for that local area.”

South Australia, where the virus was first reported, has already reported three mass mortality events involving more than 1,000 great-crested terns. Holmes says the public is also more likely to notice impacts on black swans because the birds are so large and distinctive.

Nine weeks after a migratory bird brought H5N1 to WA shores (and five years after this variant of the virus reached North America), the WA government says it is now testing the vaccine on five endangered black cockatoos at Perth Zoo.

“The feasibility of vaccinating black swans is being studied,” says Western Australian Environment Minister Matthew Swinbourn. “This is just one tool in the fight against the disease.”

Federal Agriculture Minister Julie Collins says the government has spent $113 million on bird flu preparedness, including purchasing $2 million worth of vaccines to protect captive populations of priority species.

The vaccine is produced by US animal health company Zoetis and was originally designed for use in chickens. It is not registered for use in wildlife and would need to be evaluated before its use could be extended to native birds, says Swinbourn.

Collins remained tight-lipped about the strength of the evidence that the vaccine will work in native species.

“The state and territory-led vaccination rollout has begun and will continue across the country over the coming weeks and months,” a ministerial spokesperson says.

Birds require two doses of the vaccine, given weeks apart, so vaccinating most wild populations is not feasible, experts say. Efforts have been launched to vaccinate 5,000 little penguins in wild colonies in Victoria, a process only considered possible because the colonies are well studied, accustomed to humans and return to the same burrows every night.

Short says that until now there has been a lack of investment in research to understand what avian influenza and avian vaccines do to native species.

“There were some studies done vaccinating different birds in a zoo with an H5N1 vaccine and they found that the parrots didn’t generate a very good antibody response for some reason,” Short says.

“So there are obviously species-dependent variations, and I think we really should have invested in understanding what this virus means specifically for Australia.”

Birds are already threatened

BirdLife Australia waterfowl ecologist Lindall Kidd says WA is now playing catch-up after much of its bird flu preparedness funding went to agriculture.

“Our birds are already under pressure from habitat loss due to land clearing and climate change; we could be facing death by thousands of cuts,” he says.

“There was a known gap in preparedness before the bird flu incursion, and we didn’t have enough plans in place, especially for some of our most common and widespread species. They’re the ones found in our urban areas, like pelicans and swans,” Kidd says.

She says the psychosocial effect of losing large numbers of swans will be “enormous”.

For the Noongar people of southwestern WA, the black swan is called Maarli or Kuljak and has a totemic meaning that predates its adoption as a state symbol, according to Glen Stasiuk, a Noongar researcher at Murdoch University.

“Because of its connections to brotherhood and the seasons, it is a very important bird,” Stasiuk says.

While the future of WA’s bird emblem remains unknown, Holmes lays out the possibilities simply.

“The first option is that they develop immunity to the virus, the second option is that the virus doesn’t end up reaching all of them, or the third option is that we lose them all,” Holmes says.

“I suspect the number of swans is going to decrease. Let’s hope it doesn’t go to zero. I don’t think it will, but I guess time will tell.”