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.
Sulawesi Myzomela Myzomela chloroptera is being split into M. chloroptera and M. batjanensis, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, M. chloroptera was listed as Least Concern on the basis that it did not approach the threshold for Vulnerable under any criterion. M. chloroptera (as now defined following the taxonomic change) is found in primary montane forest and secondary forest on Sulawesi and surrounding islands, Indonesia (Higgins et al. 2016), with a very large Extent of Occurrence approaching 600,000km2. It is common to scarce throughout its range, and its population trend is not known, but it is suspected to not be decreasing rapidly enough for this species to be considered threatened. Therefore, it is proposed that it should be listed as Least Concern.
M. batjanensis is found only in forest on Bacan Island, Indonesia (Higgins et al. 2016). It is restricted to an Extent of Occurrence of only c.105 km2, and so may qualify as Near Threatened or Vulnerable under criterion D2 (highly restricted range, if there is a plausible future threat that could drive the species to CR or EX in a short space of time). The population has not been quantified, but given the species’s very small Extent of Occurrence its population is unlikely to be large. Its preference for montane habitat (Higgins et al. 2016) may mean it is less susceptible to habitat loss, however, any information on potential habitat loss and population sizes may mean this species qualifies, at least, as Endangered under criteria B1ab(i,ii,iii,v);C2a(ii).
Comments are invited on these proposed categories and further information would be welcomed.
*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
Higgins, P., Christidis, L. & Ford, H. (2016). Sulawesi Myzomela (Myzomela chloroptera). 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/60355 on 9 September 2016).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
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.