by Martin G.
Here’s the first of a 2 parter on Siberian Chiffchaff ID. Part one is on plumage. Part two is on calls. Trying to make sense of my own experiences, even if limited, has helped forge much of my current thinking. A Rough Guide with summarising bullet points appears at the end.
Siberian Chiffchaffs are of course fascinating. First off they have Siberian in the name, and they really do mostly come from a large area north of Kazakhstan and even further east. They can turn up in winter months in random places (a good foot it target), often associated with water – notably sewage works (of all places). Undeniably enigmatic with (even in 2013), lively debate surrounds the precise nature of calls, their plumage and their relationship with other kinds of Chiffchaff.*
Foula, October 2007
On the issue of plumage, mid October 2007 on Foula, Shetland proved educational. I had previously seen several Siberian Chiffchaff types in the past, including notably grey birds. Residing alone in the Ham Valley for week (Foula pioneers Tim Drew and Mark Wilkinson resided at Ristie and we worked the south together each day) I scored Dusky Warbler, Yellow-browed Warbler, 2 Olive-backed Pipits and a Common Rosefinch all in the same ‘patch’. I also saw at least 2 Siberian Chiffchaff types that were easily studied. As with many on Shetland no calls were heard. The birds fed only c200 metres apart, one in a hedge the other on a grassy slope. They looked quite different from each other.
N.B. All the photos below taken by me are ‘straight from the camera’. Only cropped/resized and sometimes slightly sharpened. Unless specifically stated I have not tweaked their levels.
Siberian Chiffchaff, Foula, Oct. 2007. Bird number one. Found in the post office hedge. Though it never called, it ticked all my boxes. Very brown and buff, weak olive confined to wings, rump and tail on field views, thick buffy supercilium. ‘Swarthy’. Curiously when photos are blown up some olive is just visible on the scapulars which I never recorded in the field.
Siberian Chiffchaff, Foula, October 2007. Bird number two. I no longer have the original photo of this shot, so I guess I may have tweaked it. This bird fed openly on a grassy slope. Here looking whiter beneath than bird one, but otherwise still pretty buff and brown looking I think.
However what was striking about watching it in the field was its ability to ‘morph’ into a Bonelli’s Warbler-like plumage. It could look at least closer to ‘grey and white’ than ‘brown and buff’ with bright yellow-green fringes to the wing and tail feathers.
Above 3 photos: Siberian Chiffchaff, Foula, October 2007. Bird number two. Apart from cropping and slight sharpening, all photos as ‘from camera’. Looking quite different from bird number one; in the moment I (incorrectly) labelled it was one of those ‘grey and white Chiffchaffs’ of uncertain identity.
Above: Siberian Chiffchaff, Foula, October 2007. Same bird, number two, now looking to my eyes pretty good for my typical search image Sib. Chiff. Motion blur on the wings and where have the bright yellow-green fringes gone?
So was this a grey and white or brown and buff Siberian Chiffchaff? or both?! Certainly some birds are even greyer than this. Importantly experience has taught me that the subtle pastel plumage tones really do ‘morph’ in Siberian Chiffchaffs. I can’t exactly explain how, but they do. Browner birds can look greyer and even the most grey and white birds, in fresh plumage can hint brown and buff. No single photo (or even declaration of field appearance) can be definitive. Here’s another example.
Doncaster, December 2009
Above 4 photos. All of the same Siberian Chiffchaff, Lakeside, Doncaster, December 2009. With plumage tones of brown above and buff and white below, thick buff supercilium, pale wing bar and tobacco tinged ear coverts it ticked the plumage boxes. However it could morph colours depending on light and angle of viewing, looking either greyer-brown or warmer dun brown above and in low evening (winter) sunshine could even glow yellow in parts (when there was no yellow in reality).
Jerusalem, November 2012
Siberian Chiffchaff. Jerusalem Bird Observatory, 19th Nov 2012. More photos of this one here. A real brown job, still with nice rusty ear coverts and a variant tristis call (more on that in next post).
Oxfordshire, January 2012
Above 4 photos . Siberian Chiffchaff, Streatley Treatment Works, Berkshire, Feb 2012 by Ian Lewington. Same bird in all 4 photos. Ian described it as “appearance metamorphosed greatly depending on the light.” In the upper photo the bird’s ‘saddle’ is undeniably grey with faint olive strips. The head pattern varies from very weak looking for tristis in top photo to obviously tristis in 3rd photo.
The bird went ‘bananas’ to recording of tristis song, coming in very close, manically hopping from branch to branch and wing quivering (lowest photo). It did not respond to nominate collybita song. Meanwhile several nominate collybita present at the same site responded to collybita song but not to tristis song. This bird was one of two that gave a “perfect tristis call”.
Burjatia, Eastern Siberia, September 2009
Above 4 photos. Siberian Chiffchaff, Burjatia, East Siberia, 7th Sept. 2009 by Mats Waern. This set of photos is all of the same individual tristis, photographed east of Lake Baikal, at or beyond eastern limit of tristis range. The photos are all of the very same individual.
“The difference between the bird looking essentially brown above or essentially grey above is a minute apart, in different sun/cloud conditions. This is not primarily a photographic problem (both photos most likely give a representative image of the bird at each respective moment) but instead a problem for ALL kinds of observations of Chiffchaffs, including when handling them during ringing – they do look different in different light. This fact makes it very difficult (at least away from standardized light conditions) to discern discreet plumage types with any certainty, including ‘grey-and-white’ ones” (Magnus Hellström).
Northumberland, October 2009
Gary Woodburn’s patch is Low Newton by the Sea, Northumberland which seems to be a fairly regular spot for Siberian Chiffchaffs over several years. He writes about 3 birds seen and trapped in October 2009: 2 brown and buff, 1 more grey (and olive) and white. All uttered the same ‘peep’ call.
“In October 2009 I had three birds in the space of 10 days all calling with only a “peep” call and all eventually trapped and ringed.
The first bird from 14th – 17th Oct was not a ‘classic’ tristis looker, it wasn’t far off but was a little greyer/paler overall than most and at close range (in the hand) more olive tones were noticeable. However, in the field it looked more peachy faced like tristis and never deviated from the “peep” call.
The other 2 birds came a few days later and were more classic brown/buff birds. These were both trapped on the same day and both seemed to conform to what we currently see as classic brown/buff/white tristis.”
Siberian Chiffchaff. Gary’s first bird, described as not ‘classic’ tristis. Low Newton by the Sea, Northumberland, 14th – 17th Oct. 2009, Gary Woodburn. Clearly grey (not brown) above with subtle olive strips, the head pattern nevertheless looks pretty typical for tristis. This bird looks,to my eyes, very similar (almost identical) to that cited in Dean and Svensson (2005) from Upton-on-Severn, Worcester, under case studies of ‘grey and white tristis-like Chiffchaffs’ (plates 241-2).
Dutch Birding, December 2012
Siberian Chiffchaff- at least it’s mother was… by Vincent van der Spek. The mtDNA of this bird was tristis (mtDNA is inherited through the female line). I think I would struggle with this in the field and definitely want to hear it call! It’s certainly not a nominate collybita and reminds me of this bird in Shetland in 2012. Almost silvery -grey above with wisps of yellow-olive. Clean white looking supercilium and underparts, interrupted by bright yellow supercilium spot and what looks like a lemon wash in vent. This bird is the most extreme looking in this ground breaking paper just published. The paper covers mtDNA research on 41 Chiffchaffs trapped in the Netherlands in autumns of 2009-11. Most of these 41 were birds identified in the hand as not typical nominate collybita– some being identified as tristis and others as abietinus. I think most of the rest of the birds presented in the paper actually do look more or less like Siberian Chiffchaffs, including others identified by ringers as abietinus.
Critically in the paper all birds identified as abietinus were found to be tristis based on mtDNA (as well as all the obvious tristis). The limitation of the research is that it consisted of “birds which did not look like typical nominate collybita or from very large birds”. This, in turn, means that birds looking similar to collybita were deliberately excluded from the sampling. In fact, many abietinus in fresh plumage are so similar to collybita, that it seems likely had there been any, the ringers in the Dutch study would have overlooked them as collybita.
A photo (by Luc Knijnsbergof) of a different looking bird in the paper which is quiet olive above but with veritable tristis head pattern can be found here. It also had mtDNA of tristis. The first British Siberian Chiffchaff confirmed by DNA is here.
Vincent (Tengmalm’s) van der Spek, one of the authors comments:
“Yes, many questions remain, so we will continue this on a larger scale and with a-select sampling instead of collecting material of suspicious birds, mainly to get a better understanding of abietinus. An obvious conclusions we can draw about abietinus is that Dutch ringers have been using the wrong criteria for identification.”
Concluding tristis thoughts:
My observations to date lead me to a broad type/ search image of Siberian Chiffchaff. They vary broadly from buff /brown to grey/white with lots of subtle variation (brown-grey, grey-brown, olive-grey, olive-brown) from one extreme to the other. Any single bird can ‘morph’ it’s appearance in the field, even to raising the question of what constitutes correct perception of tones in the field (as well as in photographs ). Greyer birds often have a very similar head pattern to buff/brown birds and have the same ‘tristis‘ call. Crudely, they look like the same kind of beast.
Grey and white Chiffchaffs.
I haven’t personally seen the discreet plumage type called the ‘grey and white Chiffchaff’ described in Dean and Svensson (2005). i.e. birds which ‘lack entirely the characteristic brown and buff hues and rusty tinge of tristis’ (Alan Dean pers comms). The term ‘grey and white Chiffchaff’ has however been loosely applied to greyer looking tristis and probably held back many straightforward identifications. Of 57 individual claims of tristis submitted to the BBRC ‘tristis panel’ (see Dean et.al. 2010) there were no ‘grey and white Chiffchaffs’ as strictly applied. Whatever they are, they seem to be rare in Britain.
Hybridisation has been reported on at least a limited scale between abietinus and tristis. As such there are likely to be some birds which suggest hybrid/ intergrade or are at least unidentifiable ‘grey and white Chiffchaffs’. One such may be here. The frequency of these ‘grey and white unidentifiables’ (which do seem rare) is better established as we continue into the future (better photography and recording of all calls/song), rather than endlessly pouring over records that lack critical data. So rightly or wrongly I want plumage and sounds! If a bird essentially looks like my search image for Siberian Chiffchaff (don’t think something looking like nominate collybita and calling/singing like tristis is going to get my quick vote) and at least includes Siberian Chiffchaff ‘peep’ calls in its repertoire (including my growing understanding of ‘normal variation’), then I am calling it a Siberian Chiffchaff.
The abietinus issue
2 independent studies failed to find the presence of abietinus Chiffchaff DNA amoung Chiffchaffs in late autumn and winter in the U.K. and the Netherlands. It is clear that our understanding of both the appearance of abietinus Chiffchaffs, and its occurrence in Western Europe is flawed. We are back at square one with many new questions about this taxon. The logical extension of the Dutch Birding paper is that any Chiffchaffs befitting the title ‘non-collybita’ and wintering in Britain are more likely to be tristis than abietinus.
Above 3 photos: Chiffchaffs at Jerusalem Bird Observatory, Israel, 19th Nov. 2012. I wonder if these are abietinus on migration? With a grey undercoat to head and upperparts, overlain with yellow-olive strips, broad white supercilium and whitish underparts punctuated with clean bright yellows. Photos of abietinus, some of which certainly fit the appellation of ‘grey and white Chiffchaff’ can be found here.
The BIG QUESTION thrown up by the Dutch Birding paper (and other UK based research see here) is that our understanding of the occurrence of abietinus in Britain is all wrong. It may be a genuinely rare bird. There are some ringing recoveries of birds from e.g. Sweden in Britain, however most of the Finnish population heads southeast on migration (BWP). Has the status changed? Perhaps most of the population of abietinus now heads southeast or some occur very briefly earlier in the autumn?
One analogy might be to see abietinus Chiffchaffs as the ‘Baltic Gull of the warbler world’. Baltic Gull (nominate Lesser Black-backed Gull), breeding in Scandinavia once recorded all over Britain, is now understood to be a very rare bird whose populations largely heads in the wrong direction to regularly reach Britain. In the interim as more research is undertaken, it would not be wise to claim abietinus as late autumn/ winter visitor in Britain. The choice, the Dutch paper would suggest, is between collybita and tristis.
For completion I was intrigued as to the true appearance of the Common Chiffchaffs of the Middle East- particularly as they call very like tristis. But it seems they don’t look like ’em:
Above: To compare with brevirostris this is a nominate collybita Common Chiffchaff, from same latitude and same time of year as the brevirostris photos further up. Campelles Girona, Spanish Pyrenees, June 2009 © JL Copete
Caucasian/ Mountain Chiffchaff
And just to complete the set. Variously considered to be either 2 subspecies lorenzii and sindianus or 2 full species separated as Caucasian Chiffchaff, P. lorenzii and Mountain Chiffchaff, P. sindianus.
P. s. sindianus: Pamir-Altay mountains of central Russia/CIS east to the northwest
P. s. lorenzii: Caucasus: mountains of northeast Turkey and northwest Iran, breeding
above 1800 m a.s.l.
Caucasian/Mountain Chiffchaffs also give a monosyllabic very tristis-like ‘peep’ call. As Chiffers go distinctive looking beasts with distinct warm browner plumage above; mahagony on the crown with often short looking white supercilium arching over the eye. I was under the impression that the fringes to flight feathers were supposed to be white. José Luis Copete and Lars Svensson put me right. Fringes to remiges and rectrices can appear white, be pale brown and sometimes with yellowish or olive tinge. See below:
A rough guide to plumage issues:
- tristis varies from brown to grey looking above with/without olive bits and extra little bits of yellow can be present. Head plumage often distinctive.
- Same bird can ‘morph’ appearing both brown and grey (to do with light ‘n stuff).
- Brown/buff hues are limited to season. Many mid-winter and spring birds become greyer and can lose buffs and browns.
- abietinus – need to start from scratch on its appearance and occurrence. Likely a rarity in Britain?
- Choice for most autumn/winter Chiffchaffs is either collybita or tristis.
- The term ‘grey and white Chiffchaff’ has been confusingly used. Originally applied to autumn birds completely lacking buff and brown tones (these normally being present to some degree on the head patterns of most tristis). The particular ‘grey and white Chiffchaff’ plumage intended by Dean and Svensson (2005) seems to be rare in Britain n.b. identifiable Siberian Chiffchaffs are much more common.
- There are still occasional birds which defy easy identification due to plumage/sound peculiarities. These are worthy of the most careful study with the aim of collecting as much data on them as possible. They may be best left unidentified.
- There is still stuff to be discovered particularly about the precise extent of any hybridisation between tristis/abietinus and the degree of introgression of abietinus characters into the western tristis population. We are all learning!
* Key ID papers