A south-east Asian Locustella bush warbler has been found to consist of cryptic species after analysis of its songs, biometrics and DNA.
Russett Bush Warbler Locustella mandelli is a widespread and fairly non-descript species ranging from the eastern Himalayas across to The Philippines and Indonesia. Previously considered to involve between one and four separate species, and to settle this number, the authors performed analyses of specimens from each part of its range involving DNA, biometrics and vocalisations.
Central Chinese individuals of L mandelli were found to differ notably in all three categories with very little overlap, and were separated by both geographical distribution and altitude when their ranges met. The authors consider the endemic central Chinese birds to be differentiated enough to constitute a news species, which they have described as Sichuan Bush Warbler L chengi.
The research also confirmed the species level status of Benguet L seebohmi, Javan L montis and Tay Nguyen L idonea Bush Warblers, as well as highlighting the potential vocal differences of an unnamed population in western Myanmar, for which there are no specimens at present.
Alström, P, Xia, C, Rasmussen, P C, Olsson, U, Dai, B, Zhao, J, Leader, P J, Carey, TG J, Dong, L, Cai, T, Holt, P I, Manh, H L, Song, G, Liu, Y, Zhang, Y, and Lei, F. 2015. Integrative taxonomy of the Russet Bush Warbler Locustella mandelli complex reveals a new species from central China. Avian Research 6: 9.