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.
Stripe-breasted Rhabdornis Rhabdornis inornatus is being split into R. inornatus and R. rabori, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, R. inornatus was listed as Least Concern on the basis that it did not approach the threshold for Vulnerable under any criteria; and was considered uncommon (Kennedy and Miranda 2016). R. inornatus (as now defined following the taxonomic change) is found in submontane and montane forest in the Philippines, on the islands of Biliran, Leyte, Mindanao and Samar (Kennedy and Miranda 2016). Its population is suspected to be in decline due to widespread habitat destruction (Kennedy and Miranda 2016). However, there have been no estimates of population size and trend size, but the species does use forest edge and secondary growth (Kennedy and Miranda 2016). It is unlikely that this species meets the threshold for listing as Vulnerable, and is proposed to be listed as Least Concern. However, further information is requested as to the possible rates of population decline across the newly defined range.
R. rabori has been recorded on Panay and Negros islands in Philippines (Kennedy and Miranda 2016). The species has been only rarely observed on Panay (Kennedy and Miranda 2016) and deforestation has greatly affected the species’ habitat on Negros (only 4% of forest remained in 1988), such that this species is now only found in a limited number of remaining forest patches (Kennedy and Miranda 2016). Its restricted and fragmented population means that the global population size is unlikely to exceed 10,000 mature individuals, and each sub-population is unlikely to be large (possibly <1,000 mature individuals). Therefore, it may qualify for listing as Vulnerable under criterion C2a(i).
Comments are invited and further information would be welcomed.
Kennedy, R. & Miranda, H. (2016). Stripe-breasted Rhabdornis (Rhabdornis inornatus). 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/59954 on 30 August 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.