São Tomé Thrush Turdus olivaceofuscus has been split into T. olivaceofuscus and T. xanthorhynchus following Melo et al. (2010). Prior to this taxonomic change, T. olivaceofuscus was listed as Near Threatened under criteria C1; D1, on the basis that although the population was estimated to number 1,000-2,499 individuals, there was no evidence of a decline in the overall population.
Following this taxonomic change, Dallimer et al. (2010) recommend that T. olivaceofuscus be listed as Least Concern based on observed densities in primary forest and because the species is considered to be common across the entire island in most habitats. However, the species’s Extent of Occurrence is estimated at only 860 km2, with its population surely numbering fewer than 2,500 individuals. It is still potentially threatened by the destruction and degradation of optimal habitats, as well as the continued degradation of already modified habitats. In particular, there is concern over the removal of shade trees from cocoa plantations, as well as the compounding effects of land privatisation and road building (del Hoyo et al., 2005). In addition, many nests are destroyed by brown rats Rattus norvegicus (del Hoyo et al. 2005). Although there is no evidence of a decline in the population, there are ongoing threats that could be impacting the species.
For all of these reasons it is proposed that the species be listed as Near Threatened under criteria B1a+b(iii,v); C1; D1. Comments are invited on this proposed listing as well as further information on the species.
Dallimer, M., Melo, M., Collar, N. J. and Jones, P. J. (2010) The Príncipe Thrush Turdus xanthorhynchus: a newly split, ‘Critically Endangered’, forest flagship species. Bird Conserv. Int. Published online 27 July 2010. Accessed 21/10/2010: http://journals.cambridge.org/download.php?file=%2FBCI%2FS0959270910000390a.pdf&code=9c9cc1f4e3b45c06d298f403f4d38dc7
del Hoyo, J., Elliott, A. and Christie, D. (2005) Handbook of the Birds of the World, vol. 10: Cuckoo-shrikes to Thrushes. Barcelona, Spain: Lynx Edicions.
Melo, M., Bowie, R. C. K., Voelker, G., Dallimer, M., Collar, N. J. and Jones, P. J.
(2010) Multiple lines of evidence support the recognition of a very rare bird species –
the Príncipe thrush. J. Zool. doi: 10.1111/j.1469.7998.2010.00720.x.
Following his post on 9 December 2010, Ricardo Faustino de Lima has submitted the following figures (not BirdLife data):