Southern forms of Chiffchaff Phylloscopus collybita : observations from Iran and Armenia.
© A. R. Dean
Common Chiffchaff Phylloscopus collybita caucasicus, Armenia, May 2018.
Despite the advances afforded by molecular genetics, taxonomy remains an inexact science. Opinions vary, not only on species and subspecies boundaries but over the appropriate criteria to be employed in reaching taxonomic decisions. This situation is nowhere better exemplified than in the Chiffchaff complex. The BOU now follows the IOC World Bird List which (in version 8.2, June 2018) recognises six subspecies of Common Chiffchaff Phylloscopus collybita viz. P. c. collybita, P. c. abietinus and P. c. tristis in the northern part of the species’ range and P. c. brevirostris, P. c. caucasicus and P. c. menzbieri further south. See Clement, Helbig & Small (1998), Copete & López (2013) and Figure 1 below for details of the subspecies’ ranges, so far as they are established currently. Hereafter, each taxon and also (Caucasian) Mountain Chiffchaff P. sindianus lorenzii are referred to succinctly by their subspecific names.
The locations of Kalerdasht and Kiasar, in Iran, superimposed on range map for caucasicus and menzbieri (and other southern races)
as portrayed by Copete & López (2013) and modified from Handbuch der Voegel Mitteleuropas, Glutz von Blotzheim & Bauer (1991).
The distinguishing features of the southern forms of Common Chiffchaff, brevirostris, caucasicus and menzbieri, are far from firmly established. All have been described as similar and as close in appearance to abietinus (e.g. Clement et al. 1998) but references to menzbieri habitually acknowledge the lack of current information and an absence of photographs. Other accounts suggest that, as a group, the southern forms are somewhat intermediate between abietinus and lorenzii but closer to the former, being rather browner than typical abietinus and with reduced yet still-evident olive and yellow hues.
Several recent publications have reviewed, and in some cases questioned, the validity of the current treatment of the southern Common Chiffchaff subspecies. Copete & Lopéz (2013) considered that, in most of Turkey, Common Chiffchaffs attributed to brevirostris were indistinguishable from collybita while the appearance and biometrics of Chiffchaffs in Georgia and Armenia, attributed to caucasicus. recalled abietinus, as did those in eastern Turkey. Of caucasicus, they noted that photos of type specimens provided to them by Vladimir Loskot (who described the form in 1991) exhibited upperparts similar to abietinus but 'yellow much more clearly present on the edge of the wing, lower parts clearly whiter'. The legs were also noted to appear densely black, more so even than in tristis. They considered that the material they had examined showed a consistent appearance but concluded that examination of a longer series was required to confirm the validity of caucasicus.
The form menzbieri is even more enigmatic. Its heartlands are in the Kopet Dagh of Turkmeniya, while there are very few specimens in collections. Treatments in the literature are inconsistent and in some respects implausible. Presumably on the basis of a deficit of olive and yellow, Chiffchaffs from NE Iran to SW Transcaspia (i.e. the range associated with menzbieri) were included in tristis (or ‘fulvescens’) by Vaurie (1959), Williamson (1962) and Cramp et al. (1992), though the last added that it might belong with abietinus..
Watson (1962), in his paper recommending reinstatement of the name brevirostris for the Chiffchaffs breeding in northern Turkey, provided a table of comparative characters of brevirostris, abietinus, menzbieri and lorenzii.. The distinguishing features included in the table are very rudimentary but the word 'brown' is allocated only to the upperparts of lorenzii. The description for the upperparts of abietinus is 'greyish green' and for brevirostris 'greenish grey' (implying that brevirostris is the greyer form). Watson described the upperparts of menzbieri as 'mostly grey, tinged greenish' [my emphasis] but it seems unlikely that this was based upon examination of original material.. He noted a west-to-east reduction in lipochrome pigment (as in the northern forms), resulting in whiter underparts, with reduced yellow streaking. The underparts of menzbieri he described simply as: 'white, no yellow'.
Elsewhere, comments on the appearance of menzbieri presented in European literature are generally no more than a reiteration of earlier accounts, deriving from the type description (Shestoperov 1937) or Dementiev & Gladkov (1954, English translation 1968), for example. The form caucasicus was not described, by Loskot, until 1991. Hence, these historical accounts of menzbieri do not mention, yet alone compare, caucasicus.
One of the very few accounts based upon first-hand observations of menzbieri in the Kopet Dagh, its core range, is that of Marova & Leonovich (1997). They noted that this region is rarely visited by ornithologists and also that the original type specimens were destroyed in a fire. This has no doubt contributed to the dearth of clear documentation in the literature. Discussing distribution, the authors noted that Kopet Dagh was the established range but they included citations to menzbieri in the Elborz mountains of northern Iran. They suggested that the Elborz population was probably menzbieri but acknowledged that further information was required. This account provided explicit comments on the comparative appearance of menzbieri and caucasicus. It is in Russian but includes an English summary, from which the following is an extract (verbatim):
'Contrary to Ph. c. abietinus, Ph. c. menzbieri has only a trace of yellow colour on the breast, white belly and white undertail coverts. From Ph. c. caucasicus it differs both in the bright yellow colour of the axillars and the wrist and in the brighter green colour on the back and on the edge of the primaries and tail feathers.' However, Irina Marova (in litt.) states that, while the appearance of menzbieri has little in common with tristis or lorenzii (contra some earlier literature), the differences between menzbieri and caucasicus noted by Marova & Leonovich (1997) are relatively small.
Mitochondrial genetic data presented by Helbig et al.(1996) found that the 'pairwise sequence divergence value' between caucasicus and abietinus was 1.3% (c.f. 1.0% between collybita and abietinus and 1.7% between tristis and abietinus). However, the divergence value between caucasicus and brevirostris was only 0.2%. Although based upon limited sample sizes, these results suggest that caucasicus and brevirostris together exhibit statistically significant genetic distance from abietinus but that they are themselves very closely related, at least as inferred from mtDNA. There were no specimens of menzbieri available for analysis.
Against this background, it was to be expected that, in their 'Handbook of Western Palearctic Birds' published in July 2018, Hadoram Shirihai and Lars Svensson would review the taxonomy of Common Chiffchaff. They have adopted a revised taxonomy that recognises unequivocally only collybita, abieitnus and tristis, with a caveat-laden inclusion also of menzbieri. The traditional brevirostris is subsumed with collybita while caucasicus is incorporated with abietinus (c.f. the comments of Copete & Lopéz(2013) described above). Shirihai & Svensson variously compare menzbieri with tristis exhibiting 'fulvescens' traits ('westerly tristis') or with pale and brown-tinged examples abietinus. They conclude that: it is difficult to agree with Marova & Leonovich (1997) that it is 'a well-defined subspecies'. Nevertheless, they include a photo attributed to menzbieri on the basis of its N Iran location (their distribution map extends east from the Kopet Dagh across the Elborz Mountains but the text includes provisos). Perhaps surprisingly, in the context of the main text, the caption to the photo states: 'Reduced green or olive above and only limited trace of yellow below characteristic of this form'.
The revisions adopted by Shirihai & Svensson are based primarily upon appearance and takes little account of vocalizations. They note the tristis-like call of the traditionally recognised southern races but clearly regard this as simply geographical variation within abietinus. There are no sonograms and differences in songs revealed thereby by e.g. Helbig et al. (1996) are unacknowledged. This is a singular approach and contrasts with that of Helbig et al. who, as well as genetics, investigated songs and calls in detail and wrote: ‘... vocal differences, like mitochondrial DNA sequences, reflect evolutionary differentiation within the chiffchaff complex over long time spans much better than does morphology, which is relatively uniform'.
The relative merits of morphology and vocalisations in reaching taxonomic decisions is another debated topic but, certainly, sonograms reveal significant vocal traits and divergences within the complex. The songs of the southern subspecies are all variants on the 'chiff-chaff' theme but pace and timbre vary while sonograms reveal distinct note structures. Counter-intuitively, the calls of the southern forms do not match the rising 'huit' call of collybita and abietinus but are very similar to the 'straight', plaintive 'eeep' call of tristis.
Establishing the precise distribution, distinguishing characters and appropriate taxonomy of the forms is hindered by their relative unfamiliarity and their somewhat inconsistent treatment in the literature. It remains 'a work in progress'. Despite their revised taxonomy, Shirihai & Svensson recognise that .more research is required 'in the entire area under discussion' .
The following text is based upon photographs and sound-recordings of Common Chiffchaffs in the Elborz Mountains of Iran (which notionally span the ranges of caucasicus and menzbieri) and in the Armenian Caucasus (included within the range of caucasicus by Loskot 1991). Hopefully, the photos and sonograms provide useful additional (and relatively 'accessible') reference material but the text does not pretend to provide solutions. When visiting Iran in April 2017, the identity of Common Chiffchaffs encountered at Kelardasht and Kiaser was resolved only as 'either caucasicus or menzbieri', as both forms are deemed to occur in the Elborz (with menzbieri further east) while firm data on the appearance of menzbieri was lacking. Kelardasht is at the eastern extreme of the range depicted for caucasicus in Copete & López (2013) while Kiasar lies close to the western end of the range depicted for menzbieri (its core range being in the Kopet Dagh in Turkmenistan) - see Fig. 1 above. These two locations thus demark, approximately, an apparent gap in the depicted distributions of the Chiffchaff races. In the literature, the Hyrcanian forest of northern Iran is frequently associated with the form menzbieri but how far west menzbieri extends is not firmly established. Similarly vague is the true extent of the range of caucasicus along the southern shores of the Caspian Sea. Shirihai & Svensson (2018) map the distribution of menzbieri from Kopet Dagh west through the Elborz but this is provisional. On the basis of range, it does not seem possible to allocate the Chiffchaffs at Kelardasht and Kiasar to one form or the other.
José Luis Copete and Lars Svensson (in litt.) commented that the photos of the Elborz Chiffchaffs recalled individuals they have examined in Georgia and Armenia, which would be caucasicus under current taxonomy. During a subsequent trip to Armenia (in May 2018), a basic similarity in appearance between the Iranian and Armenian birds was certainly evident but with subtle distinctions. Differences in time, place and light conditions make it difficult to determine whether such subtle distinctions are consistent. The Armenian birds appeared marginally less grey and to exhibit a slightly more-enhanced olive component in their upperparts . Sound-recordings of songs and calls from Armenia and Iran also exhibited similarities though, again, there were minor differences (see Vocalisations below). Jointly, their songs differed significantly in terms of note-structures evident in sonograms of brevirostris, which include a dominant and distinctive 'double spurred' note not found in other subspecies (see below, Helbig et al., Clement et al. and xeno-canto recording XC142271). The Iranian and Armenian Chiffchaffs each conveyed an appearance greyer (less brown) above and cleaner and whiter below than the prevailing image of brevirostris, which is infrequently described but consistently conveyed as distinctly brown and with sullying on the underparts, at least on the flanks.
To my eye, the Iranian birds did not suggest tristis / 'fulvescens' (see above). While lorenzii encountered in Iran and Armenia certainly draw comparisons with tristis, this cannot be said of the Common Chiffchaffs. Although there is a deficit of yellow, they lack completely the 'tan-brown and buff ' hues so characteristic of tristis. With a grey tinge to their upperparts and their distinctively white underparts, with barely any yellow, there is some convergence with the 'grey and white' Chiffchaffs discussed extensively elsewhere on this website, As noted there, while 'grey and white' Chiffchaffs may include intergrades between abietinus and tristis, it is also likely that a minority of abietinus from the east of its range naturally exhibits a relatively grey and white appearance. That some abietinus are greyer and whiter than typical individuals may seem in accordance with the decision of Shirihai & Svensson to synonymise caucasicus with abietinus and to question the validity of menzbieri. However, the majority of abietinus are very similar to collybita (as emphasised by Shirihai & Svensson) and only a minority exhibit evidently greyer and whiter livery. Conversely, this appearance, especially the white underparts, are a striking and consistent aspect of the Caucasian and Elborz birds. It would seem more appropriate to say that some abietinus (a minority) approach the appearance of these southern forms rather than negate these southern forms on the basis that their appearance is approached by a minority of abietinus. Judging whether caucasicus and menzbieri differ from one another sufficiently to warrant independent taxonomic status requires further data from the Kopet Dagh, the type location, and investigation of the extent of natural variation within the two forms.
The consistent whiteness of their underparts, tristis-like calls and characteristic notes revealed in sonograms surely combine to indicate that the Armenian and Iranian Chiffchaffs are more than just an isolated population of abietinus (which would in itself raise questions). Discarding the southern forms entirely would be disproportionate and would no doubt deter the extensive research that is necessary to unravel continuing conundrums. Further details of the appearance and vocalisations of the Iranian and Armenian Chiffchaffs accompany the photographs, sound-recordings and sonograms which follow.
© A. R. Dean
Common Chiffchaff Phylloscopus collybita ssp, Elborz Mountains, Iran, April 2017.
The image above shows a Common Chiffchaff Phylloscopus collybita ssp. observed in the central Elborz Mountains near Kelardasht, in northern Iran, during April 2017. The species was quite numerous in light woodland (including oak, hornbeam and hawthorn) at an altitude of around 1500m, a habitat shared with Green Warblers P. nitidus. Chiffchaffs of similar appearance and vocalisations were encountered subsequently in denser woodlands further east, near Kiasar. Plates 3 to 6 capture their appearance particularly well and I am grateful to Ali Alieslam, Steve Rooke and Rob Tizard for providing their excellent images.
© Ali Alieslam
© Ali Alieslam
© Steve Rooke
© Rob Tizard
© Rob Tizard
Common Chiffchaffs, c. 1500m in Elborz Mountains near Kelardasht, Iran, April 2017
The appearance of the Elborz Chiffchaffs differed in several respects from that of typical abietinus. Their upperparts exhibited a strong grey component (greyer on the mantle, somewhat browner on the crown). Their underparts were conspicuously white (though slightly sullied), lacking field-evident yellow anywhere in the body plumage (though with a tinge at the front of the upper eye-ring). The upperparts were streaked with olive and there were well-developed olive-yellow fringes to the remiges and rectrices. The legs and feet were decidedly black while there was a conspicuous pale base to the lower mandible. At times the plumage appeared rather pale overall but, at close range and in duller light, a browner aspect to the upperparts was apparent. Thus, viewed dorsally in duller light conditions, they could be taken for abietinus but, viewed in profile or from below, the 'whiteness' of their underparts was consistently distinctive. Occasional abietinus exhibit plumage that is 'greyer and whiter' than in typical individuals (which much resemble nominate collybita). However, this is a minority while it is characteristic of the Chiffchaffs found in northern Iran (see also Armenia below).
At higher altitudes above 2500m, on relatively bare mountain slopes with scrub and isolated clumps of small trees, these rather grey and white Chiffchaffs were replaced by (Caucasian) Mountain Chiffchaffs P. lorenzii which, even in the brightest light, exhibited much browner upperparts (lacking olive), a distinctive fulvous-buff wash on the breast, 'plain' wing and tail edges (lacking the prominent olive-yellow fringes of the Common Chiffchaffs) and a more-prominent supercilium (together with subtly different vocalisations).
In May 2018, Common Chiffchaffs were observed, photographed and sound recorded in the Dilijan region and the Vorotan Valley in Armenia. Again, Green Warblers were found in the same habitats while at Dilijan lorenzii overlapped in altitudinal range.
© A. R. Dean
© A. R. Dean
© A. R. Dean
Common Chiffchaffs, near Dilijan, Armenia, May 2018.
Note basic similarity of Chiffchaffs in Armenia to Chiffchaffs in Iran in plates 2 to 7 but with olive more apparent in upperparts.
© A. R. Dean
Common Chiffchaff, near Dilijan, Armenia, May 2018. Close-up of wings shows contrasting yellowish fringes to flight feathers.
© A. R. Dean
Common Chiffchaff, near Dilijan, Armenia, May 2018.
Close-up of underparts, showing their distinctive white ground-colour.
Being in light shade, the underparts are not overly-illuminated nor 'burnt-out' and their basic 'whiteness' is evidently genuine.
The distinctly white-looking underparts, well-defined olive-yellow fringes to flight-feathers and 'densely black' legs accord with the impressions noted by Copete & López (2013), based upon photograph of type specimens of caucasicus provided to them by Vladimir Loskot. However, they are also consistent with the characters noted for menzbieri by Watson (1962) and Marova & Leonovich (1997) and how closely these features may be shared by the two forms remains to be resolved.
Helbig et al. (1996) and Clement et al. (1998) provided sonograms of the songs and calls of all subspecies. These are used to provide a platform by which to evaluate sound-recordings made in Iran and Armenia.
A recording of the song from Kelardasht, Iran, can be heard <here>. Compared with collybita / abietinus, the notes have a harder, 'punchier' and more staccato delivery. A sonogram appears as the upper graph in Figure 2, with comparative sonograms of caucasicus and menzbieri from Helbig et al. presented below.
Song of Chiffchaff at Kelardasht, in Elborrz Mts, Iran, April 2017.
The sonogram from Kelardasht shows simple introductory notes which also appear in the sonograms of caucasicus by J. Martens and menzbieri by I. Marova & P. Tomkovitch, published by Helbig et al.(1996) Subsequent notes are more complex but each note-structure in the Iranian recording from April 2017 has a close match in the recordings of menzbieri presented by Helbig et al. (1996). Similar though less precise matches for most notes can be found in Helbig et al.'s sonogram of caucasicus. The exception lies in the note found at the fourth, sixth and eighth positions in the Iranian recording from 2017, position six in Helbig et al.'s first sonogram of menzbieri and positions five and seven in their second sonogram. This note includes a rising 'saw-tooth' flourish or appendix positioned wholly above the base of the initial down-stroke. This is the 'hardest' note and is evident to the ear in the sound-recording from 2017. In the sonogram for caucasicus provided by Helbig et al. this note is not present. (At first sight, notes six, eight and thirteen may hint at a similar structure but in each of these notes the appendix is positioned lower and contains a gap, which indicates that a lower-frequency downward-extending 'spike' has been truncated i.e. these notes are in fact notes of the type exhibited at positions three, four and five in the first of Helbig et al.'s menzbieri sonograms). At the time of the recording (April 2017), this 'saw-tooth appendix' seemed to suggest that the song of the Elborz birds favoured menzbieri..
A recording of the song from the Vorotan Valley, Armenia, can be heard <here>.while a sonogram is provided in Figure 3.
Song of Chiffchaff in Vorotan Valley, Armenia, May 2018.
The Armenian recording from May 2018 shows a basically similar structure of notes to those from Iran in April 2017 and at positions eight and nine includes a note with a rising appendix positioned wholly above the base frequency of the initial downstroke. As the Armenian birds must be caucasicus as currently designated, this indicates that such a rising appendix is not restricted to menzbieri. It may be worth noting, however, that the appendix in the Armenia note has a far straighter, less-evidently saw-tooth structure. Listening to the songs from Iran and Armenia 'back-to-back' <here>, this saw-tooth note is distinctly more emphatic in the song of Iranian birds while the corresponding note is relatively subdued in the Armenian birds. Sonograms of menzbieri and caucasicus in Marova & Leonovich (1997) lend some support to a more-even, less saw-toothed appendix in caucasicus. This warrants further investigation, based upon additional recordings of menzbieri from Kopet Dagh.
While the note-structures of the Iranian and Armenian birds are comparable (if not wholly identical), they differ significantly from the note-structures in the sonograms of brevirostris by P. S. Hansen from Ulu Dagh, Turkey, published by Helbig et al., and in a recording by Manuel Sanchez of brevirostris from Istanbul, available on xeno-canto as XC142271. The song of brevirostris is dominated by a single, repeated note with 'double spurs', as in Figure. 4.
Figure 4. Sonogram of brevirostris song by P. S.
Hansen from Ulu Dagh, Turkey.
Reproduced from Helbig et al. (1996) & Clement et al. (1998)..
Grishchenko et al. (2016) analysed the songs of a newly-established breeding population of Common Chiffchaffs in the Crimea. They concluded that certain elements in the song were shared with caucasicus but not with abietinus and concluded that the Crimean population originated from caucasicus. Using the sonograms published in 1996 by Helbig et al. (and Clement et al. in 1998) they also concluded that menzbieri (and brevirostris too) contained subspecifically distinct elements. Unfortunately, they did not elaborate or include illustrative, annotated sonograms of all forms. so independent evaluation is not possible currently.
A recording of the call of Chiffchaffs at Kelardasht, Iran, in April 2017 can be heard <here>.
A recording of the call of Chiffchaffs in the Vorotan Valley, Armenia, in May 2018 can be heard <here>.
Figure 5 provides sonograms of the calls recorded in Iran and Armenia while, for comparison, sonograms of brevirostris, caucasicus, menzbieri and tristis are included, reproduced from Helbig et al (1996) and Clement et al. (1998).
Clearly, apart from the first call in Helbig et al.'s sonogram 'k', all these calls are relatively straight ('flat') and resemble the call of tristis. There are subtle differences in sonograms but whether they are consistent remains speculative. One of the sonograms of call attributed to caucasicus in Helbig et al. and in Clement et al.(1998) was from a recording made by J. Martens at Alamdeh (Royan), Iran, which is in the same general region as Kelardasht. It is not stated on what the diagnosis was based. Two of the calls in the menzbieri sonogram provided by Helbig et al. have a slightly 'arched' profile, hinting at a subtly 'inflected' 'sweeoo' sound. On this basis, the calls recorded at Kelardasht in April 2017 appear to match menzbieri more closely than caucasicus but those recorded further east at Kiaser appear more intermediate. Given the straighter call attributed to caucasicus from Alamdeh (near Kelardasht) in Helbig et al.'s sonogram 'k', such variations may be no more than individual variation (c.f. the variation in tristis).. The sonogram from Armenia in 2018 is also very 'straight' and matches the three calls of caucasicus in Helbig et al.'s sonogram 'k'. This very straight call is evidently the characteristic call of caucasicus but, perplexingly, the first call in sonogram 'k' , recorded in the Caucasus by J. Martens, is very different, with a strongly rising terminal pitch. Further documentation of this 'alternative' call is clearly required (see also addendum below).
In conclusion, nuances apart, the songs and calls of the Chiffchaffs in Armenia are a close if not exact match with those of the Chiffchaffs encountered in the Elborz Mountains of Iran as far east as Kiaser. However, there are subtle differences in the recordings of both song and call from the two regions. Without extensive recordings from the type location of menzbieri in Kopet Dagh, it is not yet possible to determine whether such such small difference are consistent or lie within individual variation in the vocalisations of the two forms.
Observations, photographs and sound-recordings of Common Chiffchaffs were made in April 2017 in the Elborz Mountains of Iran (east to Kiaser) and in May 2018 in Armenia. The Chiffchaffs in Armenia are attributable to the form caucasicus under current taxonomy while the Elborz Mountains of Iran span the distributions of caucasicus and the enigmatic and little-know form menzbieri. It is hoped that the material gathered may contribute to discussions of the characters, distribution and taxonomy of the southern subspecies of Common Chiffchaff, which remain vexed topics. The data support a conclusion that Common Chiffchaffs in Armenia and in the Elborz Mountains of Iran at least as far east as Kiaser share grey-tinged upperparts and strikingly whitish underparts. A browner ground-colour to the upperparts emerges in duller light conditions with olive restricted and comprising scattered streaking rather than an overall suffusion. The upperparts of the Iranian birds appeared a tad greyer and colder than those of the Armenian birds, which were a little more olive, especially considering their notionally fresher plumage (being in April, compared with May for the Armenain individuals). The decidedly whitish ground colour of the underparts is common to the Chiffchaffs in both locations, with very limited yellow streaking, which is generally undetected under field conditions. The fringes to the remiges and rectrices, however, are distinctly yellowish. The legs and feet are densely black. Such features have been associated with the form caucasicus (Loskot 1991), as discussed by Copete & López (2013), but are also compatible with comments on the appearance of menzbieri included in Watson (1962) and Marova & Leonovich (1997). Recordings of songs and calls from Armenia and the Elborz Mountains of Iran (east to Kiaser) also show a basic similarity, though again there are subtle differences. A note with a rising appendix, positioned wholly above the base frequency of the initial down-stroke is distinctive in sonograms of both forms. However, the rising appendix has a rather more 'saw-tooth' structure in the Iranian birds and a 'straighter', more-even shape in the Armenian caucasicus. Jointly, the songs from Armenia and Iran include characteristic notes not found in the songs of other subspecies, including the form brevirostris found adjacently in northern Turkey. Further information on the appearance and vocalisations of the Chiffchaffs at Kopet Dagh, Turkmenistan, are required, to clarify whether there are consistent differences from the Chiffchaffs found in the Elborz Mountains of Iran and from those in Armenia (and the remaining range attributed to caucasicus) or whether they are bridged by individual variation. The geographical distribution of these southern forms, the 'whiteness' of their underparts, their tristis-like calls and the presence of distinctively-shaped notes in sonograms of their songs set them aside from typical abietinus. While the differences are subtle, to discard entirely taxonomic recognition of the southern races would surely under-represent the true diversity of Phylloscopus collybita.
Chiffchaffs of puzzling identity are also encountered in winter in Kuwait. It has been suggested that they might be menzbieri but the basis for this seems wholly hypothetical. Although they share certain plumage features with the Elborz birds. they are less grey-tinged on the upperparts and less white below, showing restricted yet evident yellow streaking. Their call rises and falls but, compared with the Elborz birds, this is much more accentuated, being distinctly arched and reaching a higher frequency. See <here> for photos, sound-recording and sonogram. At first sight, the sonogram does not match closely any of those published by Helbig et al. and Clement et al. However, the flat opening pitch and marked rise at the mid-way point are a very close match with the first call attributed to caucasicus in sonograms 'k' above. The latter apparently lacks a subsequently descending profile, unless the recording or sonogram are truncated (the terminal fall is relatively faint in some sonograms from Kuwait). Interestingly, on the Finnish 'Tarsiger' website, there is a recording <here> by Timo Janhonen of a Chiffchaff in Azerbaijan, from March 19th 2012, that has a call which sounds near-identical to the Kuwait Chiffchaffs. A prepared sonogram shows the same distinctive shape. The breeding form in Azerbaijan is deemed to be caucasicus but the early date does not confirm birds established on territory. There were several such birds but Timo Janhonen states (in litt.) that they were in lowland shrubberies and meadows by the Caspian Sea (rather than the forest) and, consequently, it is impossible to know whether they were arriving near their breeding grounds or were migrants en route farther afield. Timo also noted a very similar call <here> on xeno-canto, recorded in Azerbaijan in January 2015 by Steve Klasan, so individuals with this call apparently winter in the region. There are still many questions to answer!
I would like to thank Ali Alieslam, Steve Rooke and Rob Tizard for discussions in the field and provision of their excellent photographs of Chiffchaffs in Iran; José Luis Copete and Lars Svensson for comments (in litt.); Irina Marova for comments (in litt.) and for providing a copy of her paper with V. V. Leonovich on menzbieri at Kopet Dagh; Roger Riddington for permission to re-use sonograms published in British Birds; Timo Janhonen for providing information on Chiffchaffs he observed and sound-recorded in Azerbaijan in March 2012; Antero Lindholm for discussions of Chiffchaffs in Georgia and surrounding regions.
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