This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for passerines.
Lynx Edicions and BirdLife International will soon publish the second volume of the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.
The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.
Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.
The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder to be incorporated into subsequent Red List updates.
Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.
Black-winged Myna (Acridotheres melanopterus) is being split into A. melanopterus, A tricolor and A. tertius, following the application of criteria set out by Tobias et al. (2010).
Prior to the taxonomic change Acridotheres melanopterus (BirdLife species factsheet) was listed as Critically Endangered under criterion A2d + 3d + 4d, on the basis that it has undergone and extremely rapid decline over the past 13 years (three generations) due to unsustainable exploitation for the cage-bird trade.
Large numbers of A. melanopterus are now being bred at specialist bird farms to supply the market, alongside Bali Starling Leucopsar rothschildi (e.g. http://anfbirdfarm.com/). However the maintenance of the wild genotypes is in no way assured in these ventures. On Bali A. tertius is apparently being reared, but other taxa may have been bred and released, at least in the past (Eaton et al. 2015). These facilities are now the main source of birds for the markets, but the maintenance of the market in this way leaves open a route to allow the continued sale of wild caught birds (Shepherd et al. 2015). The continuing demand for the birds is evident from repeated theft from these facilities by organised gangs; Cikanaga Wildlife Center was targeted ten times in a short period in June 2014 with three successful raids stealing 149 A. melanopterus and two A. tertius (Tritto and Sözer 2014, Shepherd et al. 2015).
The new nominate taxon, A. melanopterus is perhaps in the worst situation of the three newly-defined species, having almost been entirely extirpated from the wild across its former range in lowland Java (west of A. tricolor) and Madura Island over a short timeframe (Eaton et al. 2015). The remaining population is estimated to be only around 20 individuals, at two locations and some of these are considered likely to be escapes from captivity (Eaton et al. 2015).
The species is proposed to continue to qualify as Critically Endangered under criterion A2d+3d+4d, on the basis that declines in the species in the wild have been very rapid and are continuing. Additionally, it is proposed that it also qualifies under criterion C2a(i), <250 mature individuals and fewer than 50 mature individuals in each subpopulation; and criterion D, on the basis that there are fewer than 50 mature individuals remaining in the wild.
Acridotheres tricolor has been reduced to very low numbers as a result of exploitation for the bird trade (Collar et al. 2012, Eaton et al. 2015, Shepherd et al. 2015). It is restricted to south-eastern Java, east of Gunung Bromo to the east of Malang town (Eaton et al. 2015, Shepherd et al. 2015). There is no accurate population estimate for the taxon, which now appears to be restricted to Baluran and Alas Purwo National Parks where flocks of 25 and 35 individuals have been observed in recent years (Eaton et al. 2015). Additionally some birds may survive in Meru Betiri National Park (Eaton et al. 2015).
It is proposed that this newly split species qualifies as Critically Endangered under criterion C2a(i), and may qualify under criterion A2d+3d+4d, though trends for this taxon over the past 13 years (three generations) are highly uncertain.
Acridotheres tertius is endemic to the island of Bali with a population recently estimated to total around 200 birds (Shepherd et al. 2015). Most of these are found within Bali Barat National Park, with perhaps 190 individuals remaining there in 2014 (Eaton et al. 2015). A few individuals are also present in the far south of the island (Eaton et al. 2015). Birds of an unknown taxa were released on Nusa Penida in 1986 and while still present in 2011, have only been seen on the adjacent island of Nusa Lembongan more recently (Eaton et al. 2015).
It is proposed that the species qualifies as Critically Endangered under criterion C2a(ii), and may qualify under criterion A2d + 3d + 4d, though trends for this taxon over the past 13 years (three generations) are highly uncertain.
Collar, N. J., Gardner, L., Jeggo, D. F., Marcordes, B., Owen, A., Pagel, T., Pes, T., Vaidl, A., Wilkinson, R. & Wirth, R. 2012. Conservation breeding and the most threatened birds in Asia. BirdingASIA 18: 50–57.
Eaton, J.A., Shepherd, C.R., Rheindt, F.E., Harris, J.B.C., van Balen, S. (B.), Wilcove, D.S. and Collar, N.J.C. 2015. Trade-driven extinctions and near-extinctions of avian taxa in Sundaic Indonesia. Forktail 31: 1-12.
Shepherd, C. R., Nijman, V., Krishnasamy, K., Eaton, J. A. & Chng, S. C. L. 2015. Illegal trade pushing the Critically Endangered Black-winged Myna Acridotheres melanopterus towards imminent extinction. Bird Conservation International. DOI: 10.1017/S0959270915000106.
Tritto, A. & Sözer, R. 2014. Bird thieves in Java show that Indonesian wildlife crime knows no boundaries. J. Indonesian Nat. Hist. 2: 11–12.