Sunday, 2 March 2014

A bit more on Chiffs

Yesterday's interesting looking bird (see below post for more pics) 
 Chiffchaff (collybita) from this morning- lots of green and yellow tones- also pale base to bill.
Chiffchaff (collybita) from September - yellowy tones in supercilium and flanks 
Chiffchaff ssp from March 2013- a rather drab bird lacking green yellow tones- also broad pale supercilium, hint of a black lateral crown stripe and hint of buff over throat and breast, bill and legs dark
Presumed Anatolian Chiffchaff (brevirostris)- Turkey winter 2009- this bird called with a single Tristis-like plaintive note
Mountain Chiffchaff (P.s lorenzii), Kazbegi, Georgia, May 2003. One of the several recent Chiffchaff splits. 

According to HBW Common Chiffchaff (P.collybita) forms a super species with the recently split Iberian Chiffchaff (P.ibericus) and Canary Island Chiffchaff (P.ibericus). Common Chiffchaff is also closely related to the recently split Mountain Chiffchaff (P.sindianus) which is formed of two subspecies (lorenzii in the Caucasus region ((pictured above)) and sindianus in the Pakistan mountain region). Common Chiffchaff (collybita) itself is also formed of several sub-species Scandinavian Chiffchaff (abietinus), nominate Common Chiffchaff (collybita), Siberian Chiffchaff (tristis), Anatolian Chiffchaff (brevirostris), Caucasian Common Chiffchaff (caucasicus) (not to be confused with the Caucasian subspecies of Mountain Chiffchaff! and finally menzbieri Chiffchaff  which occurs in NE Iran and Turkmenia. In appearance the sub-species differ in the intensity of the yellow/green (Iberian the brightest primrose yellow to nominate yellow green) through to the prominence of brown and buff with or without olive tones (more buff brown to the south and east and more grey and mixed grey to the north and central range with a good mix in the western part of the eastern range). The calls and songs are different in many of the forms but a plaintive 'tristis'-type call can be made by Anatolian and Caucasian Chiffchaff (as well as young nominate Chiffchaffs) but there tends to be an slight inflection which can be picked up by a sonogram which is not present in Siberian Chiffchaff.   There is also a hybrid zone between Scandinavian Chiffchaff and Siberian Chiffchaff and also between Iberian and nominate. So in short- if you have an unusual greyish or brownish Chiffchaff it should be pretty simple to sort it out (for as long as you assume that nominate collybita can never show a lack of green/yellow tones)- you just need to photograph it from every perceivable angle in as many different light conditions as possible, check the colour against a standardised colour chart and fully describe the range of colours perceived in various lights and also check and describe for the full range of variable characteristics that are associated with the various forms, then sound record the call and ensure that any plaintive like notes do not have any kind of inflection in the resulting sonograms (and do not involve young collybita ) and if possible trap the thing check the wing formula for marginal differences (which could get even more marginal with increased sampling) which is suggested across the various sub-species and then take a mtDNA sample and sequence it for indicative unique haplotypes (which might just tell you what it's mother was but would not rule out the possibility of a hybrid- not to mention the possibility that further sequencing of larger numbers of a population might reveal greater diversity in genetic structure between the various populations). And don't forget that intra-population variation could throw up aberrant individuals which could call and look different suggesting other populations and whatever you do, do not forget to put all references to scientific names in italics (in case people confuse the word collybita with cauliflower)  when you write up your PhD (which you may need to make a controversial conclusion that is not rationally possible to make just because you need to make a splash for your career progression and get hold of funding to feed your family with)  on what you saw this morning for two minutes from 20 meters away recorded with a camera that distorts the real colour that existed in reality and then was able to sound record it just as it happened to start calling in that short time and flew into your net which you had handy and erected it in time in which it flew straight in, then you took a blood sample with ten people looking over your shoulder who keep saying 'Can I tick it'? 

A few comments from mates:
1. The Anonymous Birder :  
Peter!!! I'm pretty sure we are now at the stage with Chiffchaffs that we don't know what tristis or abietinus should look like or, indeed, what they are.  A few years ago this would have been a presumed abietinus -> not enough olive for collybita too much yellow (and perhaps olive) for tristis, therefore it must be something in between,... kerr-ching -> abietinus.  Given current 'knowledge' it could be tristis, almost anything could be tristis, as long as it sounds right (although if the olive in the lower scaps and at the rear of the mantle as shown in the darker shots is a true reflection of the plumage that would be odd).  Personally, I don't think we know what birds/populations the names 'tristis' and 'abietinus' refer to, the DNA stuff is ludicrous, almost every time 'eastern Chiffs' are DNA tested they come out as tristis, there has never been a genetically confirmed abietinus recorded in the UK!  This is mental!  We know via ringing that western abietinus go SW in autumn and are semi-regularly trapped in the UK whereas eastern abietinus (Finland eastwards) and presumably tristis head SE and are/should be much rarer in the UK.  The library abietinus and tristis DNA used to differentiate wandering abietinus and tristis must be up the spout which means some of the recent ID stuff is similarly useless and we are bobbing about on a phylloscopine sea of unknowing.   

To summarise: we don't know what they look like, we don't know what their DNA should look like, we might know what they should sound like,... and your bird is silent. 

The plumage tones don't look quite right for a classic tristis, but this could just be the lighting and also due to wear - don't you think this bird looks very worn? 
Con tristis:
An obvious olive tone to the mantle and scaps
The green fringes to the flight feathers not producing those classic contrasting bonelli's-like 'wing panels'
Clearly some yellow in the supercilium
Some yellow tones around the carpal
Pro tristis:
A lack of any olive on the head and neck (your pics do show a contrast in colour between the head and mantle - see image 121)
The olive tones are more uniform across the upperparts so what about a far northern abietinus? I've never seen a definite abietinus so can't comment much.
I saw a couple of tristis a few years back in Berks and these birds had more obvious very pale brown-grey tones above, especially on the mantle, but I did watch these birds in bright sunlight the whole time. There were also a coupe of pale birds with them that were not quite right.
Interesting what you say about not calling. The Berks birds hardly called in over two hours, whereas the accompanying colybita would not shut up!
Very limited experience I'm afraid but hope this helps.

Basically, as you already know the difference in colour tones on these chiffs can be amazing – See the Sibe Chiff I saw on the patch:
Your bird clearly lacks any yellow or olive tones on the UT Coverts, has very black legs and yellow “soles” of feet and subtle GC wingbar all good for Sibe Chiff, but what your bird doesn’t seem to have is that warm buffy feel to the ear coverts, which in the limited number of Sibe Chiffs I have seen always seems to stand out in certain lights.
Trouble is, as you know they are so variable – I must admit when I first saw the photos last night, it did not strike me as a Sibe, but is clearly not an obvious collybita. Be good to hear it call and abietinus would be a very good one to confirm now the Dutch have done that work suggesting abietinus is actually potentially pretty rare....
Well worth playing Sibe Chiff song to the bird, as the bird on the patch here responded well with wing quivering and Mike Langman at Broadsands has had the same.......

I think Sibe Chiffs often also look quite Bonelli’s warbler like in some lights with really bright tertial edges and retrices......


Mike Kilburn said...

A very interesting summary of the difficulties of Chiffchaff identification. Here's one from Hong Kong this winter - presumed to be tristis.

Mike Kilburn

Peter Alfrey said...

Cheers Mike