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.
Brown Bullfinch Pyrrhula nipalensis is being split into P. nipalensis and P. waterstradti, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, P. nipalensis was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. P. nipalensis (as now defined following the taxonomic change) retains much of the former range and population of the pre-split species and is still not thought to approach the threshold for Vulnerable under any criterion and hence warrants listing as Least Concern.
P. waterstradti is found only in woodland comprising native Dacrydium and introduced conifers above 1,500 m in Peninsular Malaysia (Clement 2016). The species is ‘scarce to uncommon’ (Clement 2016) with very few recent reported sightings (see eBird webpage for pre-split species: http://ebird.org/). The population size has not been directly estimated but based on an assessment of known records, population densities of closely related species and assuming only a proportion of its range is occupied, then the population size is unlikely to exceed 10,000 mature individuals. The decline in observations of this species is assumed to be a direct result of population declines, rather than a change in behaviour in this species with global warming and the consequential decline in the growth of native conifers being thought to be a potential cause of the decline (Fraser Hill blog 2015). The magnitude of the decline in this species has not been quantified, and we request any further information regarding population size and trends for this species. In the absence of further information, however, it is proposed that P. waterstradti be listed as Vulnerable under criterion C2a(ii).
Comments are invited on these proposed categories and further information would be welcomed.
Clement, P. 2016. Brown Bullfinch (Pyrrhula nipalensis). 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/61413 on 11 October 2016).
Fraser Hill blog 2015. Allen J talk on Brown Bullfinch in Fraser Hill. http://fraserhill.blogspot.co.uk/2015/12/allen-j-talk-on-brown-bullfinch-in.html
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.