Serious questions are being asked about the health of eastern Australia's ecosystem as the number of waterbirds in the region plummets close to its lowest level in 30 years.
The University of NSW's latest Centre for Ecosystem Science confirmed a long-term drop in waterbirds, showing average numbers have slumped more than 60 percent in three decades.
The bad news continued in 2015, with the survey recording a fall compared to the previous three-to-five-year period, the ABC reports.
The annual survey looked at rivers, lakes and wetlands in Queensland, NSW, Victoria and South Australia.
It also examined the important ecologies of the Murray-Darling Basin and the Riverina.
The centre's project leader Richard Kingsford told Fairfax Media the decline in waterbird numbers was a negative sign for the broader environment.
"Waterbirds are the canary in the coalmine for the ecosystem because they track all of the processes and organisms that are difficult to track at a large scale," he said.
"They are a great indicator of what is going on in the El Nino and La Nina cycles and what is going on in this drought we are in and the impact of water allocation policies."
The researchers said drought was largely to blame for the low waterbird numbers in the 2015 survey, with dry conditions causing more birds to die, or meant they were unable to thrive.
According to Kingsford, the survey results also indicated longer term environmental decay in areas like the Menindee Lakes, in far west NSW.
That area, especially around the town of Sunset Strip, was once known as an oasis in the middle of the desert, but these days most of the water has dried up.
Indeed, the Menindee Lake System is said to be at an all time low leading even to uncertainty over future water supply at Broken Hill.
Given the results of the waterbird survey, Kingsford is calling for the duck hunting season in Victoria and South Australia to be scaled back.
BirdLife Australia, a conservation group committed to protecting birds, also backed a crackdown on hunting in the wake of the survey.
The group's chief executive Paul Sullivan took to Twitter on Sunday:
Species in real trouble reportedly include the Australasian shoveler, glossy ibis and straw-necked ibis.