Abstract

ABSTRACT The systematics and morphology of Common Chiffchaff Phylloscopus collybita of the Siberian subspecies tristis are much debated. Many putative tristis in Britain are distinctly pale and frequently attributed to `fulvescens', a form initially described by Severtzov in 1873 from a series collected in Central Asia. Treatment of the taxonomy and appearance of `fulvescens' is inconsistent. It is frequently presented as an `intergrade' population resulting from unrestricted gene-flow between tristis and the North Fenno-Scandian and Russian race abietinus but this may not be the most appropriate interpretation. This article reviews the variable treatment of `fulvescens' in the literature, its differences from abietinus and east Siberian tristis and the conflicting results of research into its taxonomic status. Based on the information presented, the provenance and appearance of the pale,`grey-and-white' tristis-like chiffchaffs reported in Britain are considered.he Common Chiffchaff Phylloscopus collybita has a broad distribution across Europe and east to Siberia, with six subspecies currently recognised by most authorities. Broadly speaking, the nominate form collybita of western Europe is replaced by abietinus in eastern Europe and by tristis in Siberia. From further south in Europe, in Turkey and in Central Asia, brevirostris, caucasicus and menzbieri have been described. The `chiffchaff complex' is completed by three further closely related species of southerly distribution: Iberian Chiffchaff Ph. ibericus, Canary Islands Chiffchaff Ph. canariensis and Mountain Chiffchaff Ph. sindianus. The taxonomy and identification of the `chiffchaff complex' was discussed by Clement et al. (1998). The form tristis is frequently referred to as `Siberian Chiffchaff '