Data Zone
Justification of Red List category
Purple-chinned Starling is assessed as Near Threatened, as it is believed to have a small population of below 10,000 mature individuals and is suspected of undergoing a continuing population reduction. In addition, there is currently thought to still be a second subpopulation on Damar, although there have been no recent records. If this population is declared extinct, the species would then occur in only one subpopulation. Because of the reasonable likelihood that the Damar population is close to extinction, the assessment is based on the species approaching the thresholds for listing as threatened under Criterion C2a(ii).
Population justification
The global population size is believed to be small, and is suspected to be unlikely to exceed 20,000 mature individuals given the area of mapped range in which it is known to occur and the low bound of congeners' density estimates. The low bound is valid to use for this species: it has been described as uncommon or rare (Feare and Craig 1998), and this is backed up by the low encounter rates reported during recent visits to Yamdena (B. van Balen in litt. 2020, J. A. Eaton in litt. 2020). The largest colony located recently consisted of only 20 birds (although the species may undertake seasonal movements or be highly localised [B van Balen in litt. 2020]). With any population remaining on Damar now likely to be very small, given that multiple visits over the past 20 years have failed to record the species, and with the large uncertainty in the population size on the Tanimbar Islands, it is considered that the lower estimate may approach 10,000 mature individuals.
Trend justification
The population trend is suspected to be declining at a rate at least in line with the rate of forest loss within the range of the species. This is measured at 6% between 2000-2018 (Global Forest Watch 2020), equating to 4% over three generations of this species. However, selective logging is widespread on the island of Yamdena, and targets trees that are believed to be the key breeding resources for Purple-chinned Starling and other cavity-nesting species on the island. As such, the rate of population reduction is suspected to be higher than the rate estimated from forest loss alone.
Purple-chinned Starling is restricted to the Tanimbar Islands and Damar Island, Indonesia (Collar 2018). It appears to be uncommon or rare, with observers typically encountering only small numbers and a single conlony of 20 adults during regular visits to Yamdena (Collar 2018, J. A. Eaton in litt. 2018). The species is noted to be much scarcer than the co-occurring Tanimbar Starling A. crassa (B. van Balen in litt. 2020, J. A. Eaton in litt. 2020). There do not appear to be recent records on Damar, with none located during 30 days of fieldwork in 2001 (Trainor 2007) nor in several subsequent visits (J. A. Eaton in litt. 2020). If it is extinct on Damar, the Extent of Occurrence (EOO) of the species would be greatly reduced and may meet the initial threshold for consideration as threatened.
The species occurs in lowland forest, including records from logging roads adjacent to intact forest. The scarcity of the species indicates that it may be relatively highly dependent on primary forest. In particular, large trees are necessary for the formation of breeding colonies, and may be a limiting resource in areas with high levels of selective logging.
Significant logging and conversion of forest for small-holder agriculture is ongoing on Yamdena (J. A. Eaton in litt. 2020). Based on Global Forest Watch (2020) data, the range for this species experienced a 6% tree cover loss between 2000-2018, a rate equating to <4% over three generations.
Selective logging of large trees for timber may have a disproportionate impact on the species, as colonies are located in these trees (J. A. Eaton in litt. 2020). As such, the actual impact of the degradation and loss combined may be much more substantial than indicated by the loss detected through remote sensing.
Conservation Actions Underway
No species-specific actions are known. The species occurs within the Tanimbar Wildlife Reserve, a National protected area designation of the Indonesian government.
Conservation Actions Proposed
Conduct standardised monitoring surveys for the suite of threatened and Near Threatened birds on Yamdena to produce more accurate population estimates for this and all of the restricted range species. Protect suitable habitat, including retaining areas where no selective logging can take place. Enforce the regulations associated with the Wildlife Reserve designation within the protected area boundary.
Text account compilers
Martin, R., Fernando, E.
Contributors
Eaton, J. & van Balen, S.
Recommended citation
BirdLife International (2024) Species factsheet: Purple-chinned Starling Aplonis circumscripta. Downloaded from
https://datazone.birdlife.org/species/factsheet/purple-chinned-starling-aplonis-circumscripta on 20/12/2024.
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 20/12/2024.