Justification of Red List Category
This species is listed as Endangered as it has a single, very small population which has rapidly declined and is continuing to decline owing to the destruction of its wetland habitats.
Based on results of surveys between 2001 and 2009 conducted by Birds Australia, it is thought that the population is highly unlikely to exceed 2,500 individuals and is more likely to be between 1,000 and 1,500 individuals (S. Garnett in litt. 2009), hence the population is placed in the band 1,000-2,499 individuals. This equates to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.
The population was previously estimated at 5,000 individuals in 2000, and more recently at 1,000 to 1,500 individuals. Although this indicates a decline of greater than 50%, and is supported by presence/absence survey data, the population size in 2000 may have been an over-estimate, and the lack of reason or evidence for a decline in northern Australia makes it unlikely that such a rapid decline has occurred across the entire population (S. Garnett in litt. 2009). Therefore, a population decline of 20-49% is estimated for the past 26 years (three generations), a trend which is likely to continue into the future (C. Jones in litt. 2009).
Rostratula australis has been recorded in wetlands in all states of Australia. It is more common in eastern Australia, where it has been recorded at scattered locations throughout much of Queensland, New South Wales, Victoria and south-eastern South Australia (C. Jones in litt. 2009). The Murray-Darling Basin appears to be a particular stronghold (Thomas et al. 2010). It has been recorded less frequently at a smaller number of more scattered locations farther west in South Australia, the Northern Territory and Western Australia (C. Jones in litt. 2009). However, the relevant importance of northern and southern habitats are still subject to debate (S. Garnett in litt. 2009). The population was previously thought to number 5,000 individuals, though it is now believed highly unlikely that the population exceeds 2,500 and it may number between 1,000 and 1,500 individuals (S. Garnett in litt. 2009). Analysis of data from Birds Australia confirms that the species has been in decline. Although the precise rate is difficult to establish due to different survey methods, the cryptic nature of the species, and the lack of extensive surveys in the arid zone of northern Australia, a population decline of >30% is estimated for the past 26 years (3 generations) (Garnett et al. 2011).
Behaviour Occasional records from remote places indicate that the species can move long distances and may be dispersive or migratory, and a north-south migration has been postulated (S. Garnett in litt. 2009, R. Jaensch in litt. 2009). It is generally thought to be crepuscular, but may be nocturnal. Individuals are usually seen singly, but it may be seen in pairs and also occasionally in flocks. It breeds between August and February in southern Australia, and breeding occurs earlier in northern Australia. The female may be polyandrous, with the male incubating the clutch of 3-4 eggs and rearing chicks (Marchant and Higgins 1993). Habitat This species occupies terrestrial shallow freshwater wetlands, and occasionally brackish wetlands, including lakes, swamps, saltmarsh and claypans. Ephemeral, recently flooded wetlands appear to be especially important (Thomas et al. 2010). It will also occupy modified habitats including sewage farms, dams, bores and irrigation schemes. It constructs nests among tall vegetation, frequently on small muddy islands, but also sometimes on the shore of wetlands (Marchant and Higgins 1993). Diet It feeds on vegetation, seeds, insects, worms, molluscs, crustaceans and other invertebrates (Marchant and Higgins 1993).
The primary reason for the decline of this species is the loss of its wetland habitats. The two major causes of this loss have been the drainage of wetlands and the diversion of water to agriculture and reservoirs. It is estimated that since European settlement, approximately 50% of wetlands in Australia have been converted for other uses, with losses being even greater in some regions of the country (C. Jones in litt. 2009). Substantial declines in the reporting rate of the species in the Murray-Darling Basin coincided with major changes in the management of water resources, including the diversion of large volumes of water to irrigated agriculture (Lane and Rogers 2000). The replacement of endemic wetland vegetation by invasive weeds may also render habitats less suitable or even totally unsuitable for the species (Rogers et al. 2005). Grazing and associated trampling of wetland vegetation by cattle may also be a threat to the snipe in certain regions, particularly where grazing tends to become concentrated around wetlands in the dry season (Rogers et al. 2005). Predation by feral animals has been suggested as a threat, though there is no evidence that it is a cause of recent declines (C. Jones in litt. 2009).
Conservation Actions Underway
In 2001 a project was initiated by the Threatened Bird Network and Australasian Wader Studies Group to improve knowledge of the species (Rogers et al. 2005). Recovery actions implemented as part of this study include the development of a database of records and an assessment of habitat preferences (Rogers et al. 2005, C. Jones in litt. 2009). Birds Australia has been conducting annual surveys of the species since 2001 (S. Garnett in litt. 2009).
Text account compilers
Calvert, R., Allinson, T & Symes, A.
Garnett, S., Jaensch, R. & Jones, C.
BirdLife International (2022) Species factsheet: Rostratula australis. Downloaded from http://www.birdlife.org on 17/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/08/2022.