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.
Long-tailed Antbird Drymophila caudata is being split into D. caudata, D. straticeps, D. klagesi and D. hellmayri, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, D. caudata was listed as Least Concern on the basis that it did not approach the threshold for Vulnerable under any criterion. D. caudata (as now defined following the taxonomic change) is found at Santander and Upper Magdalena Valley in the east Andes of Colombia (Extent of Occurrence: c.60,800km2). It inhabits understorey and mid-storey bamboo in evergreen primary and secondary forest (Zimmer and Isler 2016), and may be fairly common, but locally distributed (Zimmer and Isler 2016). Habitat clearance probably is occurring in the species’s range, but there has been no quantification of the extent to which this may be affecting the species, particularly because it can inhabit secondary growth. We request further information regarding population trends for this species, but with no further information the species is not likely to approach the threshold for Vulnerable under any criterion, and so would warrant listing as Least Concern.
D.striaticeps is found in the west and central Andes of Colombia, Ecuador, Peru (east slope) and north-west Bolivia (east slope in La Paz). D. klagesi is found in the highland of north-east Colombia and north Venezuela. Both these newly split species have large ranges, inhabiting bamboo understorey and mid-storey vegetation in montane primary and secondary evergreen forest (see Zimmer and Isler 2016). While habitat destruction may be occurring in both species’s habitats, given their very large ranges this is not thought to be sufficient to warrant listing as Vulnerable under criterion A. The population of these species has not been quantified, but the pre-split species was described as ‘fairly common but patchily distributed’ (Stotz et al. 1996) and so population sizes are unlikely to be small enough to warrant listing as Vulnerable. Therefore, it is proposed that these two taxa be listed as Least Concern.
D. hellmayri is found in montane forest of the Santa Marta region of northern Colombia (see Zimmer and Isler 2016) within an Extent of Occurrence of only c.3,000km2. The remaining forest in the Santa Marta mountains is threatened by agricultural expansion, logging and burning. Possibly only 15% of the vegetation is unaltered, with the south-east slope having been extensively deforested, and on the west slope between 800 and 1,600 m much of the forest has been cleared for coffee and illegal marijuana plantations, which have subsequently sprayed with herbicide by the government (Stattersfieldet al. 1998). This species may be tolerant of some habitat degradation, but it is still suspected to be in decline. With further information regarding population size and trends this species may warrant as listing as Vulnerable or possibly Endangered. However, in the absence of any further information it is proposed that this species be listed as Near Threatened under criteria A2c+3c+4c; B1ab(i,ii,iii,v).
Comments are invited on these proposed categories and further information would be welcomed.
Stattersfield, A. J., Crosby, M. J., Long, A. J. and Wege, D. C. 1998. Endemic bird areas of the world: priorities for bird conservation. BirdLife International, Cambridge, U.K.
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.
Zimmer, K. and Isler, M.L. 2016. Long-tailed Antbird (Drymophila caudata). 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/56779 on 19 September 2016).