"I first saw ‘Subalpine Warbler’ as a young boy along steep-sided Cistus covered valleys in Portugal and was totally taken in by its behaviour, appearance and song."
The recent taxonomic review by Lars Svensson (Bull. B.O.C., 2013) of the subalpine warbler complex is perhaps a good time to examine the characters of each of the forms. I first saw ‘Subalpine Warbler’ as a young boy along steep-sided Cistus covered valleys in Portugal and was totally taken in by its behaviour, appearance and song. These first views engendered a deep interest, which still lasts today, and I have been lucky to have studied the various ‘forms’ in several countries: Western in Morocco, Spain and Portugal; subalpina on Mallorca and Corsica; and Eastern in Sicily, Greece, Israel and Cyprus, to name a few. I have also been lucky enough to find three in the UK: a spring male Eastern on Portland; a Western on Blakeney Point; an autumn male – probably Western – on Scilly. Further to this, I have studied specimens in detail at Tring as part of a review of ‘subalpine warbler’ records for the BBRC, in order to establish key features by which males could be identified in the field.
There are a number of key references, such as Shirihai et al (2001), and numerous photographs are now available on the internet, including the Surfbirds gallery (labelled with various names) .
Taxonomic treatments
The taxonomic treatment of ‘Subalpine Warbler’ was until fairly recently to divide it into three subspecies (cf. BWP, vol. VI, 1992 and Svensson, 1992): nominate cantillans (Portugal, Spain, southern France, Switzerland and Italy, including the Balearic islands, Corsica, Sardinia), inornata (NW Africa), albistriata (SE Europe). The ‘nominate’ birds breeding in the Balearic islands, Corsica, Sardinia and N Italy were largely ignored for over 50 years, but recently resurrected as the form moltonii, having first been described by Orlando in 1937. Based on birds collected in Sardinia he named it after Professor Dr Edgardo Moltoni, 1896-1980, one of the fathers of Italian ornithology.
However, the paper in Bull. B.O.C. by Lars Svensson has to some extent turned many previous treatments on their head. cantillans, previously given to western subalpine warblers is now given to eastern birds, leaving western birds to take inornata as the nominate form – previously this was the name given to birds in NW Africa. Following Svensson, we now have the following, though I have some reservations about subalpina being used instead of moltonii:-
Following Svensson, this now leaves the taxonomic situation:-
• Western Subalpine Warbler Sylvia inornata inornata and S. i. iberiae
• Moltoni’s [Subalpine] Warbler Sylvia subalpina
• Eastern Subalpine Warbler Sylvia cantiallans cantillans and S. c. albistriata
Imagine you are walking your local patch in late April and hear a fast, squeaky Sylvia song from a low bramble. You gain glimpses of blue-grey and a hint of pinky or peachy orange, a red eye, then finally it pops out and you identify it as ‘subalpine warbler’. Your head now races as you try to remember the key features by which you might tell which subalpine it is – you think, bring back the old days when things were simpler…and then it calls ‘trrrr’, just like a Wren! Oh sh…blimey! You begin to panic.
In order to ease the fear in these moments, below I list a number of characters that might help you, but note that by-and-large they refer mostly to males in spring, as in the autumn some of the subtle plumage tones and hues are obscured: above, by browner tips, below by paler creamy white tips. Further, it is my opinion that 2nd calendar year (‘2cy’ or ‘first-summer’) males, having undergone a complete body moult in winter, actually differ little in body plumage – perhaps having a tendency to more pale fringing below, but have notably worn wing coverts and remiges, by which they can be aged.
The nomenclature used for the colours (and plate numbers) comes from Ridgway’s ‘Color Standards and Color Nomenclature’, first published in 1912. I have noticed that judging the subtleties of the underparts coloration is different in the museum than in the field - for some reason, in the field orange or peach hues become enhanced. Also, it appears that colours are seen differently, by different individuals.
• Upperparts a slightly smoky or purplish grey, not quite as dusty blue and darker than cantillans, and evenly washed across the lores and ear coverts.
• Upper wing coverts, tertials and secondaries are frequently washed brown, quite rufous or tawny brown when fresh and most obvious on the outer coverts and distal edges of the tertials - hard to judge on 2cy males. The edges to the primaries can also be washed brown.
• Below the brown-orange colour is quite extensive, typically stongest on the throat and breast, but washed prominently along the flanks, but paling variably onto the central belly and undertail coverts (the latter can be clean white). The actual colour might best be described as ‘deep brownish burnt-orange’, closest to ‘wood brown’ on plate XL or ‘sayal brown’ on plate XXIX. On inornata this colour is identical in strength and hue, but often seems slightly more orange.
• The white malar streak is typically narrow, sometimes much reduced (that it may appear almost absent) and rarely more obvious.
• The call of inornata is a hard, tongue-clicking ‘tek’ or ‘tech’ and can be repeated as a ‘tech…tech’. It is similar to cantillans/albistriata, but with experience there is a subtle difference to the dry, slightly rolling ‘trret’ of those forms.
• Upperparts are paler than inornata and notably a pastel blue-grey, palest on the mantle and uppertail coverts, but darkening onto the head and can sometimes show blackish lores.
• The edges to the upperwing coverts, tertials and secondaries can show a brown wash, but rarely is this as strong as on inornata and is often a creamy brown or clean grey – the edges to the primaries likewise.
• The extent of the colour on the underparts is more restricted, with the colour of both cantillans and albistriata being strongest and largely restricted to the throat and upper breast, with a fairly marked contrast with the rest of the (off-) white underparts. On some birds the flanks appear almost unwashed with colour, but on others they can be washed with pale brick colour, but significantly lighter. The precise colour, as judged from skins, is on the easternmost form albistriata a touch redder, a ‘brick-red’ or from Ridgway, ‘mikado brown’ on plate XXIX or ‘army brown’ on pl. XL. The southern Italian form cantillans is to my eyes subtly different to albistriata, less deep, without the brick-red hue and a touch more orange (perhaps between ‘mikado brown’ and ‘cinnamon’ on plate XXIX).
• The white malar is typically broader, but note that a few inornata can match the breadth.
• Call a dry, slightly rolling ‘trret’
• The upperparts are the palest of the three species, being a soft powder or pastel blue-grey, close to cantillans, and tending to lack the slightly darker head of those forms
• Edges of wing coverts and tertials similar to cantillans, but can be a tawny coloured on outer coverts and tertials/secondaries
• The key plumage feature of subalpina is the colour of the underparts. It is notably paler than the other two species, and is best described as a dusty buff or brownish pink, paler on some birds than others (using Ridgway it is very close to either ‘avellaneous’ or ‘vinaceous-buff’ on plate XL, or just between the two). The colour is washed quite extensively across the underparts, as in inornata, but be aware that a number of illustrations and photographs of Moltoni’s in the field seem to enhance this colour, making it look an intense salmon pink (orange-pink at times), but in my field views it is rarely as bright as depicted.
• The white malar is perhaps intermediate (close to Eastern Subalpine), it can seem restricted but because the throat colour is more subdued it stands out less distinctly than in cantillans
• The call is perhaps THE diagnostic feature, and any claim should include a detailed transcription or recording (both preferably). It is very different to eastern and Western Subalpine and best described as Wren-like (maybe even likened to Red-breasted Flycatcher Ficedula parva or Spectacled Warbler Sylvia conspicillata): a rolling ‘ttrrrrrrr’, sometimes it can be slower and more drawn out over a second, with isolated ‘tek’ notes, but still gives the impression of a quite dry ‘ttrrrrrr’. The call is often noted at the beginning of or within the song.
Daniele Occhiato's website sometimes colours quite enhanced – note tail pattern in these birds
The tail patterns in both males and females of inornata and subalpina are similar and differ from those of cantillans and albistriata. Examination of birds in the hand and in museums can allow for critical details to be assessed, but applying them in the field is more problematic, though detailed photographs may show the pattern. Individuals with anything other than perfect patterns should be identified with caution.
Put simply, the second outermost rectrix on Western Subalpine and Moltoni’s Warbler, shows a small and well-defined white tip, which curves up the inner fringe and extends little or not at all up the shaft. The pattern on the third outermost feather is similar but the white much more restricted. On Eastern Subalpine Warblers of both cantillans and albistriata, the white on the second outermost rectrix extends up the shaft on the inner web, forming a significant and prominent white wedge – often the white is well-defined, but it may be more diffuse on young birds, on which the feature should be applied carefully. Such a pattern is also present on the third outermost tail feather and together gives the effect of significantly more white on the outer tail of a subalpine warbler that might be seen flying away.
The fact that the tails of Western and Moltoni’s Subalpine Warblers are similar, means separating females may not be possible.
Hopefully, using the above criteria you will be able to put a name to the bird. Concentrate on carefully assessing the subtle colour and tone of upper- and underparts – extent and strength of colour on latter, malar width and prominence. For any acceptance of subalpina, careful judgement of the call – preferably with a recording – but on the other forms also, experience of the two calls could help if you are struggling.
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