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.
Striped Manakin Machaeropterus regulus is being split into M. regulus and M. striolatus, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, M. regulus was listed as Least Concern, on the basis that it did not approach the threshold for Vulnerable under any criterion. M. regulus (as now defined following the taxonomic change) is found in Atlantic humid lowland forest in eastern Brazil between Rio de Janeiro and Bahia (Snow 2016a). This area has experienced extensive forest loss within the past 15 years (see global forest watch webpage: http://www.globalforestwatch.org/map) and this species’s population has likely been greatly reduced as a result of this (Snow 2016a). Most observations of this species now appear to be restricted to the northern part of its range (see ebird, http://ebird.org/content/ebird/), suggesting high rates of past decline in the south of its range. The global rate of decline may not be sufficient for listing as Vulnerable, but the species is suspected to be undergoing at least a moderate rate of decline, which is likely to continue. Therefore, it is proposed that this species be listed at least as Near Threatened under criteria A2c+3c+4c. We welcome any further information to see whether the rate of decline may warrant this species to be listed under a threatened category. However, the recent Brazilian Red List, which should have considered the taxon even if not recognising it as a separate species to striolatus, does not list the taxon in any of the threatened or Near Threatened categories, implying that its national classification was Least Concern.
M. striolatus has a large range, incorporating areas of lowland to mid-elevation forest in Venezuela, Guyana, Colombia, Ecuador, Peru and western Brazil (Snow 2016b). Its population size has not been quantified, but it is not thought to approach the threshold for Vulnerable, and any population declines as a result of habitat loss are not thought to approach the threshold for Vulnerable either. Therefore, it is proposed that this species be listed as Least Concern.
Comments are invited on these proposed categories and further information would be welcomed.
Snow, D. 2016a. Eastern Striped Manakin (Machaeropterus regulus). 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/57096 on 26 September 2016).
Snow, D. 2016b. Western Striped Manakin (Machaeropterus striolatus). 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/57095 on 26 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.