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 taxon Tityra leucura is to be recognised as a species by BirdLife following application of the Tobias et al. (2010) criteria, which support its distinctiveness from congeners.
Tityra leucura, White-tailed Tityra, was known only from a specimen collected in 1829, originally treated as an abnormal subadult intermediate between Tityra inquisitor albitorques and T. i. pelzelni (del Hoyo et al. 2004). There has been one known, subsequent published report of this species, with a sight record of a presumed adult male in 2006 (Whittaker 2008). This sighting took place in terra firme forest of the Rio Madeira drainage area of Amazonian Brazil, the same area where the holotype was collected (Whittaker 2008).
The extremely low reporting frequency suggests that this species is not likely to occur at high densities. However, since so little is known about the habitat requirements, distribution, and population size and trend for this species, it is very difficult to assess its threat status. With no further information available for this species it is likely that this species will be listed as Data Deficient.
Comments are invited and further information would be welcomed.
Del Hoyo, J., Elliott, A. and Christie, D. A. 2004. Handbook of the Birds of the World. Vol. 9. Cotingas to Pipits and Wagtails. Lynx Edicions, Barcelona.
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.
Whittaker, A. 2008. Field evidence for the validity of White-tailed Tityra Tityra leucura Pelzeln, 1868. Bull. B.O.C. 128: 107-113.