18/10/2013
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Three-way subalpine warbler split

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This female Western Subalpine Warbler was photographed in the core range of the new subspecies, but identification of extralimital females is still a brave call. Photo: BirdingInSpain (commons.wikimedia.org).
This female Western Subalpine Warbler was photographed in the core range of the new subspecies, but identification of extralimital females is still a brave call. Photo: BirdingInSpain (commons.wikimedia.org).
A much-predicted split of the subalpine warbler complex has now been published.

The recommendations are for three species to be recognised: Western Subalpine Warbler Sylvia inornata, which breeds in Iberia, southern France and north-west Italy; Eastern Subalpine Warbler S cantillans, breeding in central and southern Italy through to the Balkans and western Turkey; and the more markedly different Moltoni's Warbler S subalpina, found on Mallorca, Cabrera, Corsica, Sardinia and northern Italy. All differ genetically by at least 3.7 per cent – as much as several other Sylvia species – as well as in vocalisations and subtle plumage details. Western Subalpine and Moltoni's also having areas of overlapping breeding ranges in northern Italy without any apparent hybridisation.

The paper also declares a new subspecies of Western Subalpine Warbler named S inornata iberiae, a breeding endemic of the Iberian Peninsula, southern France and extreme north-western Italy. IT is consistently less yellow-tinged than the nominate subspecies, which is restricted to north-western Africa.

All three species have occurred in Britain, though Moltoni's Warbler has yet to be accepted by the British Ornithologists' Union's Rarities Committee.

Reference
Svensson, L. 2013. A taxonomic revision of the Subalpine Warbler Sylvia cantillans. Bulletin of the British Ornithologists' Club 133: 240-248.
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