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.
Chestnut-throated Apalis Apalis porphyrolaema is being split into A. porphyrolaema and A. kaboboensis, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, A. porphyrolaema was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. A. porphyrolaema (as now defined following the taxonomic change) is found in montane, gallery and secondary forest as well as forest edges between 1,600-3,400 m in the Afrotropical highlands of eastern Democratic Republic of Congo, Rwanda, Burundi, Uganda, Kenya and Tanzania (Ryan 2016a). It is locally common and there is an absence of evidence to suggest this species is in decline. Therefore, this species is unlikely to approach the thresholds for Vulnerable under any criterion and so warrants listing as Least Concern.
A. kaboboensis is found only on Mount Kabobo, eastern Democratic Republic of Congo, in the canopy of montane forest, at elevations of 1,600-2,480 m (Ryan 2016b). This species had previously been recognised by BirdLife and was then listed as Data Deficient (BirdLife International 2000), but this species probably qualifies for a threatened category. The restricted range of this species (Extent of Occurrence measured at 1,800 km2) means that the population size is likely to be low (<10,000 mature individuals) but there currently is no information regarding potential population trends occurring in this species. There is also no recent evidence about the status of this species’s forest habitat on Mount Kabobo (Ryan 2016b). Therefore, we request any comments and further information regarding population size, trend and the status of the species’s habitat. If there is any evidence for any declines then this species will likely qualify at least as Endangered under criterion B1ab(i,ii,iii,v), but in the absence of any reason to infer a decline this species may best be listed as Near Threatened, approaching the conditions for listing as threatened under criterion B1ab(i,ii,iii,v).
BirdLife International 2000. Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International.
Ryan, P. 2016a. Chestnut-throated Apalis (Apalis porphyrolaema). 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/58672 on 27 September 2016).
Ryan, P. 2016b. Kabobo Apalis (Apalis kaboboensis). 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/58673 on 27 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.