Lake Wendouree Black Swans susceptible to viral disease, according to research on the species

The study, by University of Queensland (UQ), found the Australian Black Swan lacks immune genes which helped other wild waterfowl stave off infectious diseases.

"We've got to be really conscious in our efforts in surveillance of avian flu, but also we've got to be really conscientious with our biosecurity," UQ Associate Professor Kirsty Short said.

"Ultimately, all it takes is one migrating bird to bring this virus into Australia and then based on our research, we think that we would potentially lose the black swan population."

Nature Notes writer Roger Thomas said while the Black Swan is found Australia-wide, Ballarat's particular affinity with the birds was "hard to explain".

"They're a long-term feature of Lake Wendouree," he said.

"They're certainly important for tourism and for locals. Everyone always like to see the first cygnets in early spring.

"They're probably tamer here than elsewhere ... They're easier to see closely than anywhere else [because] they're not as timid."

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The species are relatively isolated in Australia compared to other waterbirds around the world, meaning they have not had exposure to other pathogens found elsewhere that help build strong immune health.

This isolation, paired with the bird's genetics, make them particularly vulnerable to infectious disease.

Lake Wendouree's Black Swans have not had any recorded serious diseases.

While Australia has had avian flu outbreaks in the past, the disease is not currently in active here. It is widespread in Asia, Europe, North America and has recently appeared in South America, where it has "decimated" populations.

Professor Short said the UQ research made her "alert but not alarmed".

"We do have that barrier of being an island but we're certainly not 100 per cent immune to avian flu," she said.

"There was an avian flu outbreak in 2020 in Victoria so it's not impossible and I think it's now in a very unusual position with avian flu with how global [viral] events become."

When infected with a highly-pathogenic strain - that is, where the virus can replicate and move through a population quickly - a Black Swan can die within three days.

Ballarat wildlife veterinarian Dr Adrienne Lavinia said even low-pathogenic strains could be devastating for Lake Wendouree swans.

"It's still going to have really significant morbidity [and] sickness in birds," she said.

"Any birds that are either young and vulnerable or older can still have an impact."

Dr Lavinia said she supported calls for routine monitoring of the virus in Ballarat wildlife.

"There's not funding and resources for that kind of ongoing surveillance unless it's something that we're ... specifically concerned about, [then] it becomes available," she said.

"Unfortunately, that's usually when things are critical."

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