Waterbirds are not breeding at anywhere near their historic levels even as they stage a slow recovery from a mysterious drop in population last year.
New data from an annual waterbird survey led by UNSW’s Centre for Ecosystem Science with the NSW Department of Environment counted 375,419 birds across a third of the continent this year.
Last year, there were 287,231 birds compared to 579,641 birds in 2023: the 2025 population is the 12th highest surveyed, but no mass deaths have been detected (usually due to bird flu), the UNSW says.
“The total abundance of waterbirds, the number of species breeding and wetland habitat areas continue to show significant long-term decline,” says Scientia Professor Richard Kingsford, Director of the Centre for Ecosystem Science.
WATERBIRDS HIT BY EXTREME WEATHER?
Waterbirds rely on wetland habitats for breeding, but climate change, river regulation and water extraction have resulted in long-term habitat degradation, particularly in the Murray-Darling Basin, the UNSW says.
The survey results capture a country experiencing more volatile and unpredictable weather as global temperatures climb.
“We had some significant river flow and flooding events this year, with extreme rainfall in southwestern and western Queensland,” Prof. Kingsford says.
“A lot of the waterbirds have gone up in that part of the world, right out in the desert. At the same time, we also saw drier conditions persist across parts of southeastern Australia.”
DRAWN TO REFRESHED WATERS
While wetland habitats are in long-term decline, wetland areas rose this year to 334,324 hectares compared to 122,283 hectares in 2024.
Much of this extra habitat came from major inland systems: Kati Thanda–Lake Eyre, Cooper Creek, Lake Yamma Yamma and the Diamantina floodplain accounted for 51% of all wetland areas surveyed.
But these wetlands only support about 4% of the total waterbirds that were counted, the UNSW says.
The most birds were recorded at temporary saline desert wetlands — Lakes Mumbleberry and Torquinie in South Australia and Lake Galilee in Queensland — with more than 99,000 birds, nearly a quarter of this year’s population.
BREEDING REMAINS SUBDUED
The survey also shows a continual fall in breeding.
“We had a bounce in numbers after solid breeding in the flood years of 2021 and 2022,” Prof. Kingsford says.
“But now numbers are below the long-term average, with little breeding happening in 2023, 2024 and now, 2025.”
The number of nests with broods were counted at 1270 (up 10-fold on last year) for 16 species but breeding activity was still well below the long-term average and heavily concentrated at just a few sites in Queensland’s Channel Country.
Magpie geese, little black cormorants and pelicans accounted for most of the recorded breeding.
The researchers found waterbirds were strongly clustered: just 10 wetlands supported 59% of all birds counted, while about 44% of surveyed wetlands (including many that were dry) supported no birds at all.
Several duck species commonly hunted in Victoria and South Australia (such as Australasian shovelers, chestnut teal, mountain ducks, pink-eared ducks and wood ducks) were well below their long-term averages.
Five of eight game species showed significant falls in numbers over the 40-year record of the survey while some species also appear to be contracting in range.
Black ducks, mountain ducks and Australasian shovelers showed decreases in the number of wetlands they occupied.
ABOUT THE SURVEY
The survey took place from October to the first week of November this year covering 2000 wetlands across 38,000 km. Observers sat on either side of a light plan as it flew 50 metres above water; their counts were brought together for each wetland.
The survey covered inland and coastal areas from Northern Queensland down south of Melbourne with more than 70 different species of waterbirds identified.
The survey “has underpinned major management decisions,” says Dr John Porter, a Research Fellow at the UNSW Centre and senior scientist at the NSW Environment Department.
“The surveys have led to the identification of new protected areas and changed water policy in the Murray-Darling Basin,” he explains.
He says targeted releases of environmental water allocations is offsetting some of the impacts of climate change, water extraction and river regulation, but the long-term trends remain on a downward path.
As climate volatility increases, the researchers warn these long-term trends, not annual changes, that offer the clearest picture of waterbird health.
“Those trends continue to point to decline even in a year of partial recovery,” says Prof. Kingsford.
The annual survey is run by UNSW’s Centre for Ecosystem Science, supported by the NSW, South Australian, Queensland and Victorian governments.
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