BirdLife Australia undertakes Australia’s largest citizen-science effort in producing regular national assessments of the state of Australia’s birds, known as the Australian Bird Indices. BirdLife Australia also publishes an assessment of trends in bird numbers and distribution on a regional level every 5 years in the State of Australia’s Birds (BirdLife Australia 2015). The Action Plan for Australian Birds provides 10-yearly updates on the status of Australia’s bird taxa. The action plan for Australian birds 2010 (Garnett et al. 2011), assesses 27 taxa as extinct, 20 as critically endangered, 60 as endangered, 68 as vulnerable and 63 as near threatened (as at 31 December 2010). The state of Australia’s birds 2015 shows variable trends in the IUCN status of Australian bird taxa from 2010 to 2015. The number of critically endangered (possibly extinct) and near threatened species has remained stable, the number of critically endangered and vulnerable taxa has increased, and the number of endangered taxa has decreased. Overall, in the threatened categories, the number of listed taxa has risen by 1 from 147 taxa (2010) to 148 taxa (2015).
The state of Australia’s birds 2015 assesses trends on a regional level and across functional groupings of birds (including aerial insectivores, carnivores, common species, ground nesters, hollow nesters and mallee woodland–dependent species). Based on data up to 2013, major trends identified include the following (Figure BIO21):
- In the eastern mallee region, index values for common species, hollow nesters and mallee woodland–dependent species remained significantly below baseline levels (mallee woodland–dependent species being well below the baseline level).
- In the arid zone, the index values of 4 of the 6 functional groups were in significant decline by 2013. The most dramatic decline was in the carnivore group, where 12 of 20 species showed significant declines (see Box BIO9).
- In the east coast region, the index values do not show a consistent pattern. Some groups, such as rainforest-dependent species, appear to be increasing.
- In the south-eastern mainland, by 2013, index values for 4 groups were marginally above and indices for 2 groups were marginally below baseline levels.
- Mixed results (both decreases and increases) produce no consistent trend in the tropical savanna, Brigalow Belt and Tasmanian regions.
- The overall results can be judged as an overall decline in the state of birds.