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.
Red-headed Parrotfinch Erythrura cyaneovirens and Royal Parrotfinch Erythrura regia are being lumped into Erythrura cyaneovirens following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, E. cyaneovirens was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. E. regia was listed as Vulnerable under criterion C2a(i), on the basis that it having a small declining estimated population split into multiple small sub-populations (BirdLife International 2016).
E. cyaneovirens (as now defined following the taxonomic change) is found in Samoa in native, closed-canopy or degraded forest, and in Vanuatu in predominantly closed-canopy forest (Payne 2016). The only sub-population for which there has been a population estimate is in the uplands of Tongoa, where there may be 200-300 individuals (Bregulla 1998). The global population size of the pre-lump E. regia was 2,500-9,999 mature individuals based on an assessment of range size, known records, and descriptions of abundance (BirdLife International 2016), with less than 1,000 mature individuals per sub-population. However, the Samoan populations of the newly defined E. cyaneovirens are widespread, if uncommon (Payne 2016). Based on known records, population density estimates of congeners and closely related species, and assuming only a proportion of its range is occupied, the Samoan sub-population sizes are likely more than 1,000 mature individuals, and the global population of the newly defined species possibly may be greater than 10,000 mature individuals.
In Vanuatu the population is under threat from habitat loss as forest is cleared for logging and gardens on islands with large human populations (Bregulla 1992), and so the global population is inferred to be declining. Large-scale weather events may also impact upon sub-populations, with cyclones of 1990-1991 significantly affecting the Samoan sub-populations (Payne 2016). While declines are unlikely to be large enough to approach the threshold for Vulnerable under criterion A. However, the species may approach the threshold for Vulnerable under criterion C2a(i), as even though there is uncertainty over whether the global population size may exceed 10,000 mature individuals, Samoan sub-population sizes are likely to exceed 1,000 mature individuals, but may approach this threshold value. Therefore the most appropriate listing for this species this species may be Near Threatened under criterion C2a(i), although we would greatly welcome any further information regarding any population size estimates.
BirdLife International 2016. IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/10/2016.
Bregulla, H. 1998. Die Papageiamadinen von Vanuatu und den Philippinen. Gefiederte Welt 122: 188-192.
Bregulla, H. L. 1992. Birds of Vanuatu. Anthony Nelson, Oswestry, U.K.
Payne, R. 2016. Red-headed Parrotfinch (Erythrura cyaneovirens). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/61158 on 16 October 2016).
Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. 2010. Quantitative criteria for species delimitation. Ibis 152: 724–746.