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.
The newly described taxon Hemitriccus cohnhafti is to be recognised as a species by BirdLife following application of the Tobias et al. (2010) criteria, which support its distinctiveness from congeners.
H. cohnhafti, Acre Tody-tyrant, has been found only at the type locality for this species, at the Brazil-Bolivia border in the south-east of the Brazilian state of Acre (Zimmer et al. 2013). It has only been found in secondary growth vegetation and forest edge habitats near the Rio Acre (Zimmer et al. 2013), and its tolerance of such habitats means that it may be able to cope with future habitat degradation to some degree (Zimmer et al. 2013). However, there has been extensive and ongoing habitat destruction in the areas around the type locality for this species, particularly for ranching (Zimmer et al. 2013), which may be causing a population decline. Further surveys in the surrounding region have failed to find this species, but Zimmer et al. (2013) state that it is likely to occur in the Department of Pando in Bolivia and Department of Madre de Dios in Peru given their proximity to the type locality. The population size of this species has not been quantified, but given the lack of records it is unlikely to be very large. However, further surveys, particularly in potentially suitable habitat in Bolivia and Peru may be able to help conclude how abundant this species may be.
Based on current knowledge it has an Extent of Occurrence of only c.15,000 km2, and the lack of observations of this species suggest that its global population is patchily distributed or fragmented throughout this already fragmented landscape (Zimmer et al. 2013). Therefore, it may qualify as Near Threatened under criterion B1ab(i,ii,iii,v), but if the species is thought to be severely fragmented in its distribution (see IUCN 2001, 2012), then it would qualify as Vulnerable under the same criterion.
Comments are invited and further information would be welcomed.
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
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. J., Whittaker, A., Sardelli, C. H., Guilherme, E. and Aleixo, A. 2013. A new species of Hemitriccus tody-tyrant from the state of Acre, Brazil. Pp. 292-296 in: del Hoyo, J., Elliott, A., Sargatal, J. and Christie, D. A. eds Handbook of the Birds of the World. Special Volume: New Species and Global Index. Lynx Edicions, Barcelona.