Australia’s populations of threatened and near-threatened bird species have declined by 60% on average in the past 40 years, new research shows.
The threatened bird index, which is produced by scientists working with the University of Queensland, reveals some of the largest declines were among species found in South Australia and Queensland.
The index brings together almost 20,000 monitoring datasets from across Australia to measure long-term trends among threatened and near-threatened birds.
The 2023 index examined 72 species – 43 terrestrial, 13 migratory, 15 marine and one wetland species – for which enough data was available to assess trends. They include the curlew sandpiper, the helmeted honeyeater and the gang-gang cockatoo.
The scientists found the abundance of the species declined, on average, by 60% between 1985 and 2020 and that the average annual decline since 2000 was 2.2%.
“It’s not going well,” said the conservation data-scientist, Elisa Bayraktarov. “We need to do better in protecting our threatened and near-threatened birds. When we see these levels of decline we need to be thinking about conservation actions.
“First of all making sure these birds have habitat to live in – not removing any more – and removing predator species, particularly cats and foxes.”
Since 2000 terrestrial bird species showed the greatest declines (62.5%), followed by migratory shorebirds (42.5%) and marine birds (33.8%).
By state, the most significant declines since 2000 were in species found in South Australia, where populations had fallen on average 69.6%, and in Queensland, where the average decline was 65.7%.
New South Wales and the Australian Capital Territory recorded a decline of 56.3%, Victoria 47.9%, Western Australia 29.9% and Tasmania 27.6% since 2000. The trend for the Northern Territory showed a decline of only 3.4% overall but it has fluctuated significantly since 2000, driven strongly by data for migratory shorebird species.
Hugh Possingham, a professor at the University of Queensland and vice-president of BirdLife Australia, said a potential reason for the larger declines in South Australia and Queensland was the amount of land-clearing that had occurred in those states.
“In South Australia, a lot of the declines are in the agricultural regions,” he said. “A lot of habitat disappears and the bits left are fragments that are disconnected. And Queensland is the state where the most clearing continues.”
The data has been released to coincide with the Australasian Ornithological Conference, which has issued a formal statement for strong reform of federal nature laws to better protect species from extinction.
“The Albanese government is rewriting our federal nature laws right now and the outcome of this process is critical to our ability to protect habitat and implement species recovery actions,” said BirdLife Australia’s chief executive, Kate Millar.
“If we want to start turning these population trends around we need to see good, strong new laws in this term of government.”
