Reassessment of the status of Australian species and subspecies of birds was undertaken in four stages.
1. In early 2010, a complete list of the species and subspecies of Australian birds was assembled. Each taxon was assessed against the IUCN Red List Guidelines Version 8.1 (IUCN Standards and Petitions Subcommittee 2010). The IUCN Red list protocols consist of a set of rules that make up a logic tree; if a species is assessed to be consistent with the specifications of any one of five rule sets, it may be classified at that level.
Interpretations of the rules require data on a range of features that reflect the likelihood of extinction including adult population size, geographic range and occupancy, trends in population size and habitat, severe fluctuations and habitat fragmentation. The guidelines used in 2010 have been refined significantly from the version of the IUCN Red List Guidelines used for The Action Plan for Australian Birds 2000 (IUCN 1994).
2. The initial assessments were tested in workshops held in all Australian State and Territory capital cities as well as in Townsville, Queensland. Knowledgeable individuals from state and federal governments and the wider ornithological community were invited to these workshops to discuss the status of all taxa in their area, and any other taxa on which they had particular expertise. At the same time the draft list was widely disseminated among the birdwatching community, soliciting comments, as well as being sent to members of the Birds Australia Threatened Species Committee. There was also discussion outside the workshops with experts holding particular knowledge of specific taxa.
3. Detailed texts were prepared for all taxa that were to be listed as threatened or near threatened in the 2010 Action Plan. In the course of preparing these texts some new information came to light. When this occurred, experts were again consulted to determine whether they concurred with the interpretation of the new material. While the status is current as of 31 December 2010, final comments were incorporated up to 1 June 2011.
4. For all but nine taxa, agreement was reached during workshops or in subsequent discussions. For these nine, 16 members of the Birds Australia Threatened Species Committee, whose members have wide experience in IUCN Red Listing as well as specialist skills, engaged in a structured elicitation (Burgman 2005) to answer 108 questions needed to estimate the IUCN Red List parameters.
The experts were provided with background information derived from literature published on the taxon and submissions by species specialists. The experts then made an initial judgement, viewed the estimates of the same value by other committee members then provided a second, confidential estimate. The medians of the combined final results were then used to construct an IUCN Red List assessment for each taxon. For three of the nine taxa – Southern Cassowary Casuarius casuarius johnsonii, Superb Parrot Polytelis swainsonii and Gouldian Finch Erythura gouldiae – the expert panel’s judgements were further analysed using the RAMAS Red List software (Akçakaya 2007). This software takes into account the uncertainty around estimates of the true value. The RAMAS software has explicit settings for dispute tolerance and risk tolerance. In each case this was set at the default level, as it was judged that this would most closely approximate the international standards to which the project aspires.
The use of the RAMAS software produced results that differed from simple analysis of the median values provided by the expert panel who contributed to each taxon’s results, because it also included the uncertainty around judgements.