Greenish / Green Warbler

[Brian S]

Lee

I was never my intention to dismiss your point of view, and certainly not Keith's - for whom I have the highest regard, and have not heard his opinion about the bird other than secondhand.

I have seen Greenish in Finland, but never 'many', however I have been in the Madhyr Pradesh, India in the past three winters. Here, apart from Hume's Warbler (which seems abundant in some areas, e.g. Kanha and Bandhavgarh), it is the second most common Phyllosc - maybe 1000s heard or seen, whilst I have also seen a good number of 1-w Bright-green. It is interesting to note the variation in Greenish, with some birds washed more yellow than we seem to expect in the UK, but the call is so distinct that I never suspect Bright-green. When I hear a Bright-green it seems quite obvious to me, and can confirm Roy H's and Harry's comments above, 1-ws are washed quite strongly yellow below.

Just read the info from Magnus Robb on BBA; interesting, but unless I am wrong, I think that the Cornish bird only called like a Greenish, and frequently in sequence. I feel it unlikely that a Bright-green, even from Turkey, would never call like a Bright-green......

ATB

Brian S

[LeeEvans]

To be fair to Brian, he has not had the benefit of seeing all of the discussion and debate that perhaps has been instigated on the UK400 Club forum, particularly in relation to the supposed variation in contact calls and physical appearance of both first-winter and adult-type Bright Green Warblers, although it does seem like he has studied what I have published on the blog. There appears to be widespread disagreement of the specific identification of nitidus and in many areas it appears to be so difficult that some observers are very confused by what they are actually seeing and recording.

I would like to see some ringing studies, a wide selection of images showing the variation in underparts and recordings made of Bright Green Warblers wintering in Goa and Sri Lanka ande elsewhere within their distribution and I would also like to see further studies made of the dull individuals in the Uludag Mountains region of western Turkey.

Magnus is extremely keen to receive recordings made of first-winter birds in India as he feels that this is where there is a major flaw in our knowledge. OK Brian has stated that he has heard many Green Warblers and finds then relatively easy to distinguish from Greenish but for some reason, many other birders with a wealth of experience on that continent are struggling including Mike Prince who sent me some detail.

I am certainly not in a position to answer Harry's queries sadly but will try and get him some answers.

As I keep on harping on about - the Lizard bird appeared to have structural differences to typical Greenish, with a longer more broad-based bill, much brighter on the lower mandible and a more compact and rotund appearance body-wise. The greater covert bar is very prominent and yellow-washed, much more obvious than on typical Greenish. The supercilia do not meet on the forehead and they flare out behind the eye, very similar to the 1983 Green Warbler, and although very subtle, there is yellow on much of the underparts and the bird is very dingy beneath, not typically silvery-white.

I realise that I am never going to be able to prove that the bird is a Green Warbler and the fact that it lacks yellow on the chin and throat (and lacks the extensive yellow wash that first-winter nitidus reportedly always has) and constantly repeated the typical di-syllabic note over 60 consecutive occasions is very suggestive of Greenish Warbler. If that is the case, then we really must re-write the identification criteria for the species.

I shall continue my review of this interesting record and once I have gathered all relevant material, shall make a further pronouncement on what I have found.

[Alex Lees]

Interesting discussion and an 'interesting bird'.

I have a few further questions:

1) Is there a precedent for a Greenish Warbler staying into November before? I guess many late birds may have been binned as tristis 'type' Chiffchaffs in the recent review? Maybe you can help us out with this one Lee? The Birdguides database does not hold a record later than this one. Although this needn't have any bearing on the specfic identification of the bird, it does obviously suggest that this individual probably isn't a Scandinavian drift migrants and could well have come from a long way east - as a vagrant with a 'deviant' migratory orientation. How much variation is there within viridanus Greenish? Given that the majority of the birds UK observers see are assumed to be from Fennoscandinava, could this have any bearing on people's perception of variation in viridanus? I guess Brian is best placed to answer that, although how useful are skins in this case?

2) Green Warbler was split in the TSC's 5th report, yet I can find no data on the utility of contact calls in separating the species there. Elsewhere we had been told in Collinson et al. (2003): 'The call of nitidus is similar to that of plumbeitarsus and different from that of typical viridanus, although within viridanus itself it is certainly variable'.
Has Lars Svensson published any of the data that prompted the split (he did present some of it aurally here). It just seems like a big u-turn to me from the earlier statement in Collinson et al.:

Variation within both nitidus and the other Greenish Warbler taxa makes the diagnosability of ‘Green Warbler’ uncertain. The yellow colour of the supercilium, and sides of head and neck, would probably fulfil diagnosability criteria if this character was present in all individuals, yet this has been shown not to be the case. With further research, it might possibly be shown that, in addition to the molecular differences, viridanus and nitidus are 100% diagnosable on the basis of a combination of plumage and biometric characteristics. In the absence of this evidence, we have to conclude that nitidus is still best regarded as a subspecies of P. trochiloides at present.

So, what exactly changed and can we get the DB paper on here? I appreciate that there has been much evidence gleaned here from personal experience, but exactly what has been committed to paper on the subject?

cheers

Alex

[mafting]

Originally Posted by Alex Lees

it does obviously suggest that this individual probably isn't a Scandinavian drift migrants and could well have come from a long way east - as a vagrant with a 'deviant' migratory orientation.

Hi Alex, just a quick question - what's the evidence that migrants present in Britain later in the 'season' are from further east than those appearing earlier? Is this an assumption or is there good evidence to support it? Obviously the resonable assumption is that a bird coming from further away will take longer to arrive, but we know from ringing etc that some passerines can cover 000s of km in a relatively short time, so the difference between a 2000km origin and a 7000km origin might not be much (days?).

[Brian S]

Hi Lee

Just to clarify, I have not heard 'many' Bright-green Warblers, but those that I have, in the context of having heard many Greenish (and getting my 'ear in'), seemed distinct....if you see what I mean.

Brian

[LeeEvans]

There is very little published on the variation and 'real' differencies in the Greenish Warbler populations and although Lars Svensson has studied all of those labelled in the trays at Tring Museum and elsewhere, he has not made any examinations of them in the field.

If you take the labels on the Tring Museum specimens to be accurate, then trochiloides which occurs in the central and east Himalayas and in central China is markedly darker green on the upperparts and quite greyish-white below and has a shorter wing length when compared with viridanus (the western form, breeding from Finland and Poland east through western Siberia to the Yenesei River, south through NW Mongolia to northern Afghanistan and the NW Himalayas, the Tian Shan mountains and the west Pamir range).

In the western Himalayas, the form ludlowi is described, this form being somewhat intermediate between the two forms above, again being a shorter distance migrant bearing a shorter wing projection, paler green above and quite olive-grey around the underparts.

There is also a much more restricted form obscuratus, occurring to the north of the nominate form in central China. Again, quite deep green on the upperparts with a very contrasting head pattern, the supercilia being notably white in many individuals.

[Marcus]

Alex (et al),
RBA have kindly published the article here hopefully it isn't subscribers only (if it is then sign up for a free trial).

This has been a great thread and although it would be far to easy to state that Lee is "just after a tick" this would be incredibly disingenuous as he is clearly trying to help fill a gap in the knowledge base for the Greenish Warbler complex. Thanks to all involved.

[Alex Lees]

Originally Posted by mafting

Hi Alex, just a quick question - what's the evidence that migrants present in Britain later in the 'season' are from further east than those appearing earlier? Is this an assumption or is there good evidence to support it? Obviously the resonable assumption is that a bird coming from further away will take longer to arrive, but we know from ringing etc that some passerines can cover 000s of km in a relatively short time, so the difference between a 2000km origin and a 7000km origin might not be much (days?).

Hi Richard

It is an assumption, based on the fact that you can roughly organise the median arrival dates of rare Phylloscs: Greenish, Arctic, Yellow-brow, Raddes, Dusky, Pallas's, Hume's which fits roughly with a distance-based model. Saying that Eastern Crowned comes from even further away and would slot in before the bulk of the Pallas's I guess. There are likely to be species-specfic departure dates so maybe ECW sets off earlier than Pallas's anyway? What we do know about sibe Phyllsocs is that the first arrivals in Finland of YBW occur in late August yet they don't make the UK until mid Sept so I don't think they are in that much of a hurry to get here (although it would be within their physiological limits to achieve this as you point out).

Either way an 'eastern origin' its just a working hypothesis to explain the 'problems' with the bird's appearance and might explain why the bird doesn't fit the search image some observers have for Greenish Warbler. Equally, I think however that this bird does provide a good working example to test the field identification of nitidus...

Alex

[MichaelF]

based on the fact that you can roughly organise the median arrival dates of rare Phylloscs: Greenish, Arctic, Yellow-brow, Raddes, Dusky, Pallas's, Hume's which fits roughly with a distance-based model

Not well at all! There's also a strong latitude-of-origin component, with southerly species (from where the summer lasts later) moving later than more northerly origin species: not a lot of difference in the distance Yellow-browed and Hume's come, but southern origin Hume's is typically a month or two later than Y-brows. Ditto e.g. Brown (NE origin, typically Sept-Oct) and Isabelline Shrikes (SE origin, typically Oct-Nov). Then there's also differences in ecology and migration strategy: Radde's and Dusky come the same distance from the same latitude, but Radde's are usually a few weeks earlier than Duskies.

[Alex Lees]

Originally Posted by MichaelF

Not well at all! There's also a strong latitude-of-origin component, with southerly species (from where the summer lasts later) moving later than more northerly origin species: not a lot of difference in the distance Yellow-browed and Hume's come, but southern origin Hume's is typically a month or two later than Y-brows. Ditto e.g. Brown (NE origin, typically Sept-Oct) and Isabelline Shrikes (SE origin, typically Oct-Nov). Then there's also differences in ecology and migration strategy: Radde's and Dusky come the same distance from the same latitude, but Radde's are usually a few weeks earlier than Duskies.

Agreed, that southern species arrive later but then they also have further to travel, there are tens of thousands of YBWs breeding in European Russia (in the Polar Urals), travelling west through Scandinavia these individuals have a much smaller distance to travel than Hume's, despite breeding west to a similar longitude. We are getting a little off the point, it is a sweeping generalisation but the pattern broadly holds. Greenish (and Arctic) are the most proximate breeders and are the first to arrive here in the UK and this Cornish Greenish triggers alarm bells as it is exceptionally late and may therefore not be of European or near-European origin.

Alex