Justification of Red List category
This species has a large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The species may be decreasing, however it does not meet or approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population is estimated to number less than 10,000 mature individuals, however there are thought to be more than 1,000 mature individuals in the largest subpopulation and hence it does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Population justification
The population is poorly known, but the species is described as uncommon to rare and occurs at very low population densities (Hadley and Parker 1965, G. Dutson pers. obs. 1998, Dutson 2011, G. Dutson in litt. 2023). Assuming an effective detection distance of 10 m in closed forest, densities of around 5 individuals/km2 in the mountains of Santo (likely covering less than 1,000 km2), 30 individuals/km2 on Nendo (500 km2), and <1 individual/km2 on Vanikoro (170 km2) have been suggested (G. Dutson in litt. 2023). Assuming that only a proportion of the range is occupied to account for this species' rarity, the total population is estimated to fall within the range 2,500-10,000 mature individuals (with more than 1,000 mature individuals in the largest subpopulation).
Trend justification
The species occurs at very low population densities, though there is no direct evidence of a decline. Remote sensing data (Global Forest Watch 2022, using data from Hansen et al. [2013] and methods disclosed therein) indicate slow but ongoing tree cover loss in this species range (<2% within three generations). Although there are records of the species from degraded forest and gardens, overall its tolerance of forest loss and degradation is little known; it therefore remains a possibility that ongoing forest loss and associated impacts of degradation are affecting the population (G. Dutson in litt. 2023). Considering this along with the potential impacts of invasive rats within the range that have caused rapid declines in congeners, a decline is precautionarily suspected.
Aplonis zelandica is endemic to Nendo and Vanikoro in the Santa Cruz islands of the Solomon Islands and most of Vanuatu south to Efate.
It is a forest species of the lowlands on smaller islands and uplands on the larger islands on Vanuatu (Bregulla 1992), but is also often recorded in gardens and degraded forest on Nendo and Vanikoro (G. Dutson in litt. 2009). It occurs from sea-level to over 1,000 m, but is usually commoner in hills, especially on Santo (Dutson 2011).
Although the Vanuatu highland population is presumably above altitudes threatened by logging, lowland and hill forests across the species' range are thought to be subject to this threat (Craig and Feare 2020, G. Dutson in litt. 2023), and remote sensing data indicate slow but ongoing forest loss within the range (Global Forest Watch 2022, using data from Hansen et al. [2013] and methods disclosed therein). There are records of the species from degraded forest and gardens, however overall its tolerance of forest loss and degradation is little known (G. Dutson in litt. 2023). The species may be threatened by invasive rats (Rattus spp.) within the range (a threat that has caused rapid declines in congeners) (G. Dutson in litt. 2023).
Conservation Actions Underway
No targeted conservation actions are known for this species.
Text account compilers
Vine, J.
Contributors
Dutson, G.
Recommended citation
BirdLife International (2024) Species factsheet: Rusty-winged Starling Aplonis zelandica. Downloaded from
https://datazone.birdlife.org/species/factsheet/rusty-winged-starling-aplonis-zelandica on 10/12/2024.
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 10/12/2024.