NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The Scarlet Robin Petroica boodang (Lesson 1838) is a small (13 cm) songbird with black upperparts and chin, red breast, white lower belly, a large white forehead spot, and white flashes in the wings and tail. The female is brown with a large white forehead spot, dull brick-red breast, and white flashes in the wings and tail. The male Flame Robin Petroica phoenicea is similar but has dark grey upperparts, orange-red underparts from chin to belly, and a small white forehead spot, while the female has a brown chest.
2. The Scarlet Robin is found in south-eastern Australia (extreme south-east Queensland to Tasmania, western Victoria and south-east South Australia) and south-west Western Australia. In NSW it occupies open forests and woodlands from the coast to the inland slopes (Higgins and Peter 2002). Some dispersing birds may appear in autumn or winter on the eastern fringe of the inland plains.
3. The Scarlet Robin breeds in drier eucalypt forests and temperate woodlands, often on ridges and slopes, within an open understorey of shrubs and grasses and sometimes in open areas. Abundant logs and coarse woody debris are important structural components of its habitat. In autumn and winter it migrates to more open habitats such as grassy open woodland or paddocks with scattered trees. It forages from low perches, feeding on invertebrates taken from the ground, tree trunks, logs and other coarse woody debris. The Scarlet Robin builds an open cup nest of plant fibres and cobwebs, sited in the fork of tree (often a dead branch in a live tree, or in a dead tree or shrub) which is usually more than 2 m above the ground (Higgins and Peter 2002; Debus 2006a,b). Generation length is estimated as 5 years based on the congeneric Flame Robin (Garnett and Crowley 2000)
4. In recent decades the Scarlet Robin is believed to have undergone a moderate reduction in population size in NSW based on comparative evidence from broadscale surveys. The Scarlet Robin was recorded in 43 one-degree grids in NSW during the first national bird atlas in 1977-81 at mostly moderate to high reporting rates (Blakers et al. 1984). In the second national bird atlas of 1998-2002 it was recorded in 37 one-degree grids at mostly low reporting rates (Barrett et al. 2003). Its index of abundance (reporting rate) declined significantly by 55% in NSW and 31% nationally over the 20 years between the two atlases (Barrett et al. 2003, 2007). Assuming a linear decline this is equivalent to a state wide decline of 45% of 3 generation (15 years) the time frame recommended by IUCN (2008) for estimating population change. Declines of more than 20% were recorded in the robin's core NSW bioregions (NSW North Coast, New England Tableland, Nandewar, Sydney Basin, South East Corner, South Eastern Highlands and NSW South Western Slopes) (Barrett et al. 2003, 2007). The robin was not less likely to be detected in Atlas 2 versus Atlas 1 due to the different survey methods used (Barrett et al. 2003) and therefore comparison of the two atlases is unlikely to be significantly affected by survey bias.
5. The Scarlet Robin is sensitive to habitat degradation (Watson et al. 2001, 2003; Radford et al. 2005; Radford and Bennett 2007), and overgrazing (Olsen et al. 2005). For instance, its occurrence (presence/absence) is positively associated with patch size and components of habitat complexity including increasing tree canopy cover, shrub cover, ground cover, logs, fallen branches and litter (Watson et al. 2003). In a comparison of intensively surveyed woodland sites stratified by habitat attributes and land-use category (Barrett et al. 2003), the Scarlet Robin was found to be (a) less common in isolated patches of 30 ha or less where there was no tree cover within 200 m and less than 20% cover within 1 km; (b) less common in sites surrounded by cattle grazing; (c) absent from sites surrounded by cereal cropping; (d) more common as time increased since removal of grazing; and (e) more common in sites with native versus exotic grasses if ungrazed for more than 10 years. Nest sites, food sources and foraging substrates, such as standing dead timber, logs and coarse woody debris, are susceptible to depletion by grazing, firewood collection and 'tidying up' of rough pasture (e.g. Recher et al. 2002). Core bioregions in the Scarlet Robin’s NSW range (New England Tableland, Nandewar, NSW South Western Slopes and South Eastern Highlands) are 53-84% cleared and moderately to highly stressed (landscape stress factor 3-6 out of 6) (Morgan 2000; Barrett et al. 2007). 'Clearing of native vegetation' and 'Removal of dead wood and dead trees' are listed as Key Threatening Processes under the NSW Threatened Species Conservation Act 1995. Over-abundant populations of Pied Currawong Strepera graculina, supported by exotic berry-producing shrubs, may be a potentially severe threat to the Scarlet Robin's breeding productivity (Debus 2006c), exacerbated by other native and exotic predators.
6. The Scarlet Robin Petroica boodang (Lesson 1838) is not eligible to be listed as an Endangered or Critically Endangered species.
7. The Scarlet Robin Petroica boodang (Lesson 1838) is eligible to be listed as a Vulnerable species as, in the opinion of the Scientific Committee, it is facing a high risk of extinction in New South Wales in the medium-term future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:
The species has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon:
(c) a moderate reduction in population size,
(d) an index of abundance appropriate to the taxon.
Dr Richard Major
Proposed Gazettal date: 12/02/10
Exhibition period: 12/02/10 – 09/04/10
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