This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines
Lynx Edicions and BirdLife International will soon publish 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 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), 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.
Crested Serpent-eagle Spilornis cheela is being split into S. cheela and S. minimus, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, S. cheela (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.
S. minimus is endemic to the central Nicobar Islands, including Teressa, Kamorta, Katchall, Trinkat and Nancowry, where it inhabits evergreen forest, grassland and coastal zones (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001, A. P. Zaibin in litt. 2012).
It is suggested that this species be listed as Near Threatened under criterion C2a(i), on the basis that its population probably includes fewer than 2,500 mature individuals (thus potentially meeting the thresholds for Endangered), with each subpopulation (there are perhaps two) probably numbering fewer than 1,000 mature individuals (but not fewer than 250); however, it is not clear whether the population is in decline, as the species shows considerable tolerance of modified habitats, and the rate of habitat alteration in its range is perhaps low, although some loss and degradation is expected for agriculture and development.
S. cheela (as defined following the taxonomic change, and incorporating all other forms) is widely distributed in South Asia and South-East Asia and occurs in a variety of habitats, including primary and secondary forest, plantations and wooded savannah (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). It is likely to be listed as being of Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.
Comments on these suggested categories and further information would be welcomed.
del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the birds of the world, Vol 2: New World Vultures to Guineafowl. Barcelona, Spain: Lynx Edicions.
Ferguson-Lees, J. and Christie, D. A. (2001) Raptors of the world. London, UK: Christopher Helm.
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.