Macquarie Marshes Landholders Brace for Bird Flu Outbreak

Landholders in the Macquarie Marshes are bracing for the potential arrival of the H5 strain of bird flu, which could have a devastating impact on the region's waterbird populations. The internationally recognised wetlands, near Warren in central north-west NSW, provide habitat for tens of thousands of waterbirds, including many threatened species.

Risk of Outbreak

David Duncan from the Macquarie Wetlands Association manages Burrima, a conservation property bordering the nature reserve. He said an outbreak of the H5 strain of bird flu in the marshes could be particularly damaging, given the number and diversity of waterbirds that gathered in the wetlands.

"The potential to spread there is quite high and it would be absolutely devastating if it came on the back of a flood or a colonial nesting event," he said.

Mr Duncan said bird flu would add to an existing biosecurity problem in the marshes, with feral pigs, foxes and cats already taking a significant toll on native wildlife. Introduced predators are estimated to kill millions of native animals across Australia each day, while Mr Duncan said pig numbers around the marshes had surged after several favourable seasons since the 2017–2020 drought.

"The feral pigs and cats and foxes are already creating massive damage, and they are a threat as a potential vector to spread bird flu."

Controlling Feral Pigs

Mr Duncan said controlling pigs required a coordinated approach because they could travel long distances between properties, and the responsibility should not fall solely on individual landholders.

"They move big distances. They might be on your farm one day, but they can be three or four farms away the next night," he said.

"You can't do something on your own. You've got to do something at least at a district level to try and control them. It needs to be vigilant and constant."

He said greater attention needed to be paid to biosecurity threats already present in the environment, rather than focusing on only emerging threats.

"Biosecurity is far more than preparing for or reporting the next exotic disease or pest to arrive," he said.

"It must control or eradicate the introduced species and pests that are already here, killing out native wildlife."

Impact on Waterbird Populations

University of NSW conservation biologist Richard Kingsford said waterbirds were particularly vulnerable because they congregated in large numbers at wetlands, allowing the virus to spread through contact, faeces and scavenging birds.

"They will start to concentrate, particularly in an El Niño year as those inland wetlands start to dry up, and that's a real concern," he said.

"This influenza can kill sometimes half of a population. So that's how devastating it can be for wildlife," Professor Kingsford said.

Landholders fear a bird flu outbreak could have a devastating impact on wildlife in the Macquarie Marshes.

Responding to an Outbreak

There have been no cases detected in inland NSW, but authorities are urging landholders to maintain strong farm biosecurity and keep working and pet dogs away from wild birds and carcasses.

A NSW Government spokesperson said H5 bird flu infection or disease had not been reported in beef cattle herds globally.

"Although transmission to livestock is considered low risk, there is a need for vigilance and grazing on or near wetlands like Macquarie Marshes may increase the risk," the spokesperson said.

But Macquarie River landholder and RiverSmart Australia chair, Kate Milner, said that could be difficult to implement.

"That sounds great on a piece of paper, but not in practice," she said.

"Cattle need water, and they will graze in the marshes and along the river, which is where birds congregate."

Ms Milner said landholders still had questions about the potential impacts of an outbreak, including what it could mean for backyard poultry, water supplies and access to the marshes.

"There's quite a lot of talk flying around, but nobody really knows," she said.

A community information session will be held in Warren on Thursday to give landholders more information about preparing for and responding to an outbreak.