Data Zone
Justification of Red List category
The species is thought to have declined by >30-49% in the last ten years and this is likely to continue. For this reason the species is classified as Vulnerable.
Population justification
The population of the nominate subspecies is the product of the three measures of AOO used by Newman et al. (2021) where the minimum AOO is the number of 2x2 km squares (3,700 km2) encompassing all records from Birdata (Birdlife Australia 2020), the best estimate is 20% higher (4,400 km2) due to incomplete surveying, and the maximum value is double that (7,400 km2). An average density of 9.7 birds/km² (range 3–18 birds/km²) was applied to these AOO calculations, based on consultation with experts (G.B. Baker unpublished data, in Newman et al. 2021).
Subspecies kingi occurs on King Island, which has a land area c.1.2% that of the nominate subspecies’ range. The same density of this taxon (given an identical ecology in the same habitat) is assumed and hence the population size values of the nominate subspecies are increased by 1.2% to give a global total of 36,000-73,000, with a best estimate of 43,000 mature individuals.
Trend justification
Reporting rates from several sites across Tasmania (where >95% of the global population is) indicate rapid declines over the past 10 years.
The reporting rates that are available from systematically collected 2-ha 20-min surveys, 500-m radius and 5-km area searches (BirdLife Australia 2020) declined by 65% (500-m) and 35% (5-km) in north-western Tasmania; by 94% (500-m) at Pyengana in north-eastern Tasmania; and, in south-eastern Tasmania, by 51% (2-ha) at Meehan Range, 64% (5-km) on Tasman Peninsula, and 62% (2-ha) at North Bruny Island.
Elsewhere, the trends are less consistent. Trends in the reporting rate across the entire range are inconsistent (+19% 2-ha, -48% 500-m; BirdLife Australia 2020) but these are subject to more inter-annual variations in effort compared to the more robust systematic surveys, thus are considered a less robust trend measure. Population trends were positive at one site: 43% (500-m) at South Arm and a separate analysis of 72 sites in the Midlands, Tasmania, found no significant difference between 1996–1998 and 2016 (Bain et al. 2020), but there was no monitoring in the intervening period. In north-west Tasmania, declines from 2000–2019 were 86% (500-m) and 94% (5-km). Given that similar trends are apparent at widely dispersed locations, but that there is some inconsistency, it is concluded (following Newman et al. 2021) that the population as a whole has declined by 30%–49% in the last decade. The trend of the King Island population (subspecies kingi) is unknown, however with a land area 1.5% of that of Tasmania, it is unlikely to disrupt the global trends presented herein. Given the uncertainty over what has caused these declines, the rate of decline over the next 10 years is not estimated.
Dusky Robin occurs throughout Tasmania as well as on Maria, Bruny and Flinders Islands, and other islands in the Furneaux Group (Higgins and Peter 2002). There is also an additional subpopulation (subspecies kingi) present on King Island.
Dusky Robins occur in most open habitats up to 1,200 m including dry sclerophyll forest, the ecotones between forests and clearings, coastal heathland and sedgeland, and button grass Gymnoschoenus sphaerocephalus plains, especially in recently burnt areas. There they feed on invertebrates, mainly insects, and occasionally seeds, obtained on the ground or in trees. They typically sit on stumps or posts and dart to the ground for prey, but occasionally hop along the ground or forage among foliage or in the air. They build untidy cups of grass, bark and rootlets in the cavity of a stump, the bole of a eucalypt, a tree fork or a bark crevice in which they usually lay three eggs (Higgins and Peter 2002).
Reasons for the population decline are not understood and may not have ceased. Land clearing has been removing some habitat given that up to 40 ha can now be cleared without a permit (FPA 2020). Although they often feed in burnt areas (Higgins & Peter 2002), fire may have affected birds at some sites, and fire frequency and intensity are expected to increase (Di Virgilio et al. 2019, Dowdy et al. 2019). Changes in the abundance of Tasmanian Devils Sarcophilus harrisii, which may have affected predation rates by other predators (Hollings et al. 2014, Fancourt et al. 2015), may warrant investigation and cats Felis catus may take some individuals given their ecology (Woinarski et al. 2017). Drought may have contributed to some declines (Newman 2017; Newman et al. 2020, 2021), an aspect of climate change likely to intensify.
Conservation Actions Underway
Some subpopulations and their habitat conserved as World Heritage Area or National Parks.
Conservation Actions Proposed
Continue to monitor population trends. Determine reasons for population declines. Understand demography and ecology with respect to climate variables (drought). Develop appropriate management interventions. List as threatened under appropriate legislation. Secure key occupied habitat patches from degradation and loss.
Text account compilers
Berryman, A., Vine, J.
Contributors
Butchart, S. & Ekstrom, J.
Recommended citation
BirdLife International (2024) Species factsheet: Dusky Robin Melanodryas vittata. Downloaded from
https://datazone.birdlife.org/species/factsheet/dusky-robin-melanodryas-vittata on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.