The Principe Thrush Turdus xanthorhynchus: a newly split, 'Critically Endangered', forest flagship species

Recently recognised as specifically distinct, the Principe Thrush Turdus xanthorhynchus is endemic to the island of Principe in the Gulf of Guinea, West Africa. Formerly treated as conspecific with the more abundant T. olivaceofuscus from the nearby island of Sao Tome, the Principe Thrush is considered rare and likely to be restricted to primary rainforest. A 2007 survey of Principe comprising 177 point transect locations covering 13 sites under different land uses (six in primary forest, three in secondary forest and four in plantations) encountered 18 individuals. Thrushes were found only in primary rainforest, where overall densities were 0.10 birds ha(-1), equating to a population size of 435 individuals (95% confidence intervals: 208-913). We adjusted this estimate to take into account the fact that the highest density (0.22 birds ha(-1)) only occurred above 600 m, giving a final estimated population size of only 364 birds (95% confidence intervals: 186-887). In light of evidence of recent declines, possibly driven by hunting pressure, in the number of mature individuals and the limited area of occurrence of the species, the IUCN Red List category for the Principe Thrush should be 'Critically Endangered' under both criteria B1a+b(iii and v) and C2a(ii). The recent designation of the primary forests of southern Principe as a protected area (Parque Natural d'Obo do Principe) provides an opportunity for the conservation of this newly described species, which we recommend is used as a flagship for the forests as a whole.