In 2023, a comprehensive update to Australia’s Threatened Bird Index (TBX) occurred. This is the first major update to the bird index since it was first released in 2018. This significant update occurred in collaboration with BirdLife Australia, the largest data contributor to the Threatened Bird Index to date. This page provides users with a summary of the results from the Threatened Bird Index 2023. The full set of trends for the bird index can be explored using the TSX trend visualiser tool here.
Figure 1: The Threatened Bird Index 2023, showing trends up to 2020 across all bird taxa.
Interpreting the index graphs
The index shows the average change in populations compared to a base year. It shows a relative change and not population numbers themselves. The base year of our index is 1985, which gets an index score of one. A score of 1.2 would mean a 20% increase compared to numbers in 1985 on average, while a score of 0.8 would mean a 20% decrease compared to 1985 on average.
Threatened Bird Index 2023
The dataset
Taxa represented …………………………………………….…………. 72 (up 14 from 2018)
Terrestrial birds ……………………………………….……….…….. 43 (up 8 from 2018)
Shoreline (migratory) birds ……………………….……….……. 13 (up 3 from 2018)
Marine birds …………………..……………………….………….…… 15 (up 4 from 2018)
Wetland birds ………………………………….……….…….…….. 1 (down 1 from 2018)
EPBC listed taxa represented …………………………………………………….……………..58
National priority taxa represented ..…………………….………………….………………….9
IUCN listed taxa represented (threatened) ………….……………….…………………..29
IUCN listed taxa represented (near threatened) ..……..………….…………………. 10
2020 Bird Action Plan listed taxa represented ..……………….…….…………………58
Total data sources ………………………………………..……….…… 54 (up 15 from 2018)
Total number of time series ……………………..…..… 19,814 (up 9,065 from 2018)
Total number of sites …………………………………..…. 10,784 (up 6,548 from 2018)
Key findings: Headline trends
- At the national scale, threatened and near-threatened bird species continue to trend downward, with an average decline of 60% in relative abundance since 1985 for the 72 species represented (Figure 1). Overall, the relative abundance of threatened and near-threatened bird species in the TBX database has declined by 2.2% per annum since the year 2000.
- Among groups with adequate data, terrestrial birds showed the greatest declines (62.5%), followed by migratory shorebirds (42.5%) and marine birds (33.8%), since the year 2000.
- The most significant declines since 2000 across all species were in South Australia (69.6%) and Queensland (65.7%).
- The ACT and New South Wales recorded a decline of 56.3%, Victoria 47.9%, WA 29.9% and Tasmania 27.6% since 2000.
- The trend for NT showed a decline of only 3.4% overall but the trend has fluctuated significantly since 2000, driven strongly by data for migratory shorebird species.
