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.
Rearrangement of a selection of Amaurospiza species; A. relicta (formerly a subspecies of Blue Seedeater Amaurospiza concolor) is to be recognised as a species, with the remnants of A. concolor being lumped with A. moesta and A. carrizalensis as a newly defined A. moesta, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, Amaurospiza moesta was listed as Near Threatened under criteria A2c+3c+4c, on the basis that it was suspected to be declining moderately rapidly throughout its range as a result of habitat loss and degradation (BirdLife Internatioal 2016a). A. concolor was listed as Least Concern on the basis that it did not approach the threshold for Vulnerable under any criterion. A. carrizalensis was listed as Critically Endangered on the basis that it was believed to have an extremely small and declining population within a very small range (BirdLife International 2016b). Following the taxonomic change A. moesta now no longer approaches the threshold for Vulnerable, with a very large range, and suspected large population size. Habitat loss may be causing declines, but this is not likely to be sufficiently large to approach the threshold for Vulnerable, and so it is proposed that this species be listed as Least Concern.
The newly defined A. relicta is found in dense forest borders and secondary undergrowth as well as humid pine-oak woods and cloudforest between 1,200 and 2,500 m in the mountains of Guerrero, Morelos and Oaxaca, in south-west Mexico (Rising and Jaramillo 2016). The population is suspected to be stable (Rising and Jaramillo 2016), and so while it has been described as rare and local (Rising and Jaramillo 2016), it is not thought to approach the threshold for Vulnerable under any criterion. It would therefore warrant listing as Least Concern.
BirdLife International 2016a Species factsheet: Amaurospiza moesta. Downloaded from http://www.birdlife.org on 04/10/2016.
BirdLife International 2016b. Species factsheet: Amaurospiza carrizalensis. Downloaded from http://www.birdlife.org on 04/10/2016.
Rising, J. and Jaramillo, A. 2016. Blue Seedeater (Amaurospiza concolor). 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/62144 on 4 October 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.