In a recent taxonomic paper, Lars Svensson summarised the latest research on the taxonomy of the Subalpine Warbler (Sylvia cantillans s.l.) and recommended the split of the complex into three different species (Svensson 2013):
Western Subalpine Warbler (Sylvia inornata), with two subspecies:
- S. i. inornata: breeding in Northwest Africa. Before this taxonomic revision, Sylvia cantillans inornata was the name of the North African birds, now inornata will become the nominate subspecies of the Western.
- Sylvia inornata iberiae subsp. nov.: a new subspecies described in the paper for the birds breeding in the Iberian Peninsula, southern France and extreme northwest Italy. See the map below.
Eastern Subalpine Warbler (Sylvia cantillans), with two subspecies:
- S. c. cantillans: breeding mainly in central and southern Italy. The taxon cantillans, historically associated with the birds breeding in the Iberian Peninsula, is now the nominate subspecies of the Eastern Subalpine Warbler. This is because the type of cantillans was described from two specimens collected in Italy (Baccetti et al. 2007) and found out to belong to the Eastern. Thus the need to find a new name for the Iberian birds, which Svensson did by describing iberiae.
- S. c. albistriata: breeding in the Balkans and western Turkey.
Moltoni’s Warbler (Sylvia subalpina): breeding in Mallorca, Sardinia, Corsica and northern Italy. Despite the overlap between Moltoni’s Warbler and cantillans in northern Italy, there is no evidence for gene flow between the two species (Brambilla et al. 2008). The correct scientific name for this species is Sylvia subalpina rather than Sylvia moltonii following the recommendation by Baccetti et al. (2007) and Svensson (2013).
- Baccetti, N., Massa, B. & Violani, C. 2007. Proposed synonymy of Sylvia cantillans moltonii Orlando, 1937, with Sylvia cantillans subalpina Temminck, 1820. Bull. B.O.C. 127: 107-110. PDF
- Brambilla, M., Vitulano, S., Spina, F., Baccetti, N., Gargallo, G., Fabbri, E., Guidali, F. & Randi, E. 2008. A molecular phylogeny of the Sylvia cantillans complex: cryptic species within the Mediterranean basin. Mol. Phylogenet. Evol. 48: 461-472. DOI: 10.1016/j.ympev.2008.05.013
- Svensson, L. 2013. A taxonomic revision of the Subalpine Warbler Sylvia cantillans. Bull. B.O.C. 133: 240-248. PDF
As a follow up of the taxonomic paper cited above, Svensson published a new paper about the identification of different species in the ‘Subalpine Warbler complex’. Here is the summary as published in the website of British Birds:
In this paper, Lars Svensson summarises the current knowledge of variation within the Subalpine Warbler complex. 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, Moltoni’s Warbler and Eastern Subalpine Warbler. 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 on 13th June 1894.
Svensson, L. 2013. Subalpine Warbler variation and taxonomy. British Birds 106: 651-668.
The Collins Bird Guide was updated in May 2015 with the additions of a number of new species (splits), and amended texts, captions and new plates for other species. Of interest to birds of Northwest Africa, the updates included the split of the African Crimson-winged Finch (Rhodopechys sanguineus), the split of the Saharan Scrub Warbler or Maghreb Scrub Warbler (Scotocerca saharae), and the split of the Subalpine Warbler complex into three species (plate in photo 3). See the website of Rare Bird Alert UK for the full list of the updates.
Update 3 (Dec 2017): the PDF of the taxonomic paper is online (added the link above). The same for the paper about a new North African subspecies of Common Chaffinch described by the same author.