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.
Blue-and-white Flycatcher Cyanoptila cyanomelana is being split into C. cyanomelana and C. cumatilis, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, C. cyanomelana was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. Work by Leader and Carey (2012) identified that the previous assessment that there were only 2 subspecies to C. cyanomelana – C. c. cyanomelana and C. c. cumatilis to be incorrect and that an additional subspecies C. c. intermedia should be recognised. C. c. intermedia actually represents most of what had formerly been considered as C. c. cumatilis and has been retained in the newly defined C. cyanomelana (Leader and Carey 2012). This newly defined C. cyanomelana is not through to approach the threshold for Vulnerable under any criterion and hence would warrant listing as Least Concern.
The newly defined C. cumatilis is only known from a few localities (Leader and Carey 2012) and its distribution remains uncertain, in particular its non-breeding distribution. Leader and Carey (2012) suggest that it could breed in the area that roughly corresponds to the Shanxi Mountains Endemic Bird Area, China (see BirdLife International 2016), although the species has not been actually recorded in Shanxi (Leader and Carey 2012). The pre-split species inhabits lowland to submontane forest during the breeding season (Clement 2016), and so it is assumed that this species may inhabit a similar habitat. Much of the forest in the potential range of this species has been cleared which may mean that breeding populations are now fragmented, and forest clearance is continuing, though possibly not at the same extent as historically (see Hansen et al. 2013). Therefore, it may be inferred that the population is undergoing a continuous decline.
The paucity of records of this species within its suggested breeding range suggest that this species is either under-recorded or particularly rare, and given the limited amount of habitat remaining in its known breeding range it is possible that the population size may be small. However, based on an assessment of known records, its suspected range size and using population density estimates of closely related species and an assumption that only a proportion of its range is occupied, the population size is still likely >10,000 mature individuals. The lack of reports of this species is concerning, though, and so it is conservatively suggested that the species be listed as Near Threatened under criterion C2a(ii) as the population size may approach 10,000 mature individuals. We would however, greatly welcome any further information regarding this species, particularly information regarding its potential nonbreeding range and any population size estimates.
BirdLife International 2016. Endemic Bird Area factsheet: Shanxi mountains. Downloaded from http://www.birdlife.org on 13/10/2016.
Clement, P. 2016. Blue-and-white Flycatcher (Cyanoptila cyanomelana). 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/59077 on 13 October 2016).
Hansen, M. C., P. V. Potapov, R. Moore, M. Hancher, S. A. Turubanova, A. Tyukavina, D. Thau, S. V. Stehman, S. J. Goetz, T. R. Loveland, A. Kommareddy, A. Egorov, L. Chini, C. O. Justice, and J. R. G. Townshend. 2013. High-Resolution Global Maps of 21st-Century Forest Cover Change. Science 342: 850–53. Data available on-line from: http://earthenginepartners.appspot.com/science-2013-global-forest. Accessed through Global Forest Watch on 10th October 2016. www.globalforestwatch.org
Leader, P.J. and Carey, G.J. 2012. Zappey’s Flycatcher Cyanoptila cumatilis, a forgotten Chinese breeding endemic. Forktail 28: 121-128.
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.