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.
Icterine Greenbul Phyllastrephus icterinus is being split into P. icterinus and P. lorenzi, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, P. icterinus was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. P. lorenzi had recently been considered a synonym of P. icterinus and as such had been considered a subspecies of that taxon (see Birdlife International 2016). Following the Tobias et al. (2010) criteria, P. lorenzi has been re-split from P. icterinus.
P. lorenzi is known from several scattered localities in north-eastern and eastern Democratic Republic of Congo and Bwamba in the west of Uganda in primary forest between 600 and 1,580 m (Fishpool and Tobias 2016). This species had previously been treated as Near Threatened under criterion B1ab(i,ii,iii), but using a minimum convex polygon it has a re-assessed Extent of Occurrence of >200,000km2, and so this species does not warrant listing as Near Threatened. The species is apparently scarce (BirdLife International 2016) and it is intolerant of secondary and disturbed habitat (see Fishpool and Tobias 2016). Therefore, habitat degradation and clearance in its fragmented range may be causing the population to decline. The population size has not been quantified, but it is not currently thought to approach the threshold for Vulnerable (<10,000 mature individuals with a decline of 10% over 3 generations or a given population structure). We request any further information regarding potential population sizes and trends, but in the absence of any further information it is suggested that this species be listed as Least Concern.
BirdLife International 2016. Species factsheet: Phyllastrephus icterinus. Downloaded from http://www.birdlife.org on 28/09/2016.
Fishpool, L. and Tobias, J. 2016. Sassi’s Olive Greenbul (Phyllastrephus lorenzi). 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/57997 on 28 September 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.