Abstract
The current knowledge of variation within the Subalpine Warbler complex is summarised. A new morphological character, regarding differences in the tail pattern, is described here, which will help in the diagnosis of taxa away from the breeding grounds. This new character is central to the proposal of a three-way split of the complex: Western Subalpine Warbler Sylvia inornata, Moltoni’s Warbler S. subalpina and Eastern Subalpine Warbler S. cantillans (see Svensson 2013). Based on current knowledge of morphological characters and confirmed by genetic sampling, it is established that the first British record of Moltoni’s Warbler was a male on St Kilda, Outer Hebrides, on 13th June 1894.