Join for FREE
It only takes a minute!
Discover the ZEISS Digital Nature Hub

Welcome to BirdForum.
BirdForum is the net's largest birding community, dedicated to wild birds and birding, and is absolutely FREE! You are most welcome to register for an account, which allows you to take part in lively discussions in the forum, post your pictures in the gallery and more.

Phylloscopus from Tainan, Taiwan, April 2020

Reply
 
Thread Tools Rate Thread
Old Wednesday 29th April 2020, 02:18   #1
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Phylloscopus from Tainan, Taiwan, April 2020

Presumably a Two-barred Warbler, I find the colour scheme of this one peculiar (although it may be being affected by surrounding foliage). I’ve only seen autumn Two-barreds before, and they’ve tended to appear a lot more contrasty. The wingbar also looks short.

There were some vocalisations: a trisyllabic 'chir-wee-wee' call note and an abrupt, almost Hartert’s-like ‘pit-su-i’ song note. The call does fit Two-barred, but the plumage still seems odd. Will fresh spring Two-barred look like this?

Vocalisations: https://drive.google.com/file/d/1Ydy...ew?usp=sharing
Attached Thumbnails
Click image for larger version

Name:	Phylloscopus SP (01) - Copy.jpg
Views:	106
Size:	334.4 KB
ID:	725605  Click image for larger version

Name:	Phylloscopus SP (09) - Copy.JPG
Views:	76
Size:	275.9 KB
ID:	725606  Click image for larger version

Name:	Phylloscopus SP (04) - Copy.JPG
Views:	145
Size:	252.9 KB
ID:	725607  Click image for larger version

Name:	Phylloscopus SP (08) - Copy.JPG
Views:	101
Size:	275.5 KB
ID:	725608  
SteveMM is offline  
Reply With Quote
Old Wednesday 29th April 2020, 09:21   #2
HouseCrow
Registered User

 
Join Date: Aug 2003
Location: netherlands
Posts: 268
Hi
I'm a beginner at (East Asian) leaf warblers, hoping to learn and still struggling with the relatively few Japanese options, so
'presumably Two-barred' because of the calls? This could be one of the arctic complex for me (i'm a beginner remember)


Could you maybe elaborate a bit more?

thanks!
Gerben
__________________
observado.org records: https://bit.ly/2zb9MdW

inaturalist bird records: https://www.inaturalist.org/observat...onic_taxa=Aves
HouseCrow is offline  
Reply With Quote

BF Supporter 2019 Support BirdForum With A Donation

Old Wednesday 29th April 2020, 09:37   #3
Grahame Walbridge
Registered User

 
Join Date: Jan 2015
Location: Portland
Posts: 2,586
Quote:
Originally Posted by SteveMM View Post
Presumably a Two-barred Warbler, I find the colour scheme of this one peculiar (although it may be being affected by surrounding foliage). I’ve only seen autumn Two-barreds before, and they’ve tended to appear a lot more contrasty. The wingbar also looks short.

There were some vocalisations: a trisyllabic 'chir-wee-wee' call note and an abrupt, almost Hartert’s-like ‘pit-su-i’ song note. The call does fit Two-barred, but the plumage still seems odd. Will fresh spring Two-barred look like this?
A very intriguing individual Steve. Vocalisations sound good for Two-barred but one must not forget there is some overlap/variation within the complex.

Plumage-wise it does look odd and one wouldn't immediately jump to Two-barred, not least because of the reduced greater covert bar and the apparent lack of a median covert at a time when it should be in very fresh plumage. Plumage tones are also a little odd but this may be influenced by the surroundings as you allude. I would expect the upper parts to appear a little darker green in tone.

Trawling the net I came across this individual from Beidaihe in early May with reduced wing-bars so possibly your bird represents one end of extreme variation?
https://pbase.com/eken/image/124970966

Grahame
Grahame Walbridge is online now  
Reply With Quote
Old Wednesday 29th April 2020, 09:39   #4
andyadcock
Registered User
 
andyadcock's Avatar

 
Join Date: Dec 2005
Location: UK and Occasionally St Petersburg, Russia
Posts: 18,786
Looks most like Greenish to me but seems to lack the dark bill tip?
__________________
Andy A
andyadcock is offline  
Reply With Quote
Old Wednesday 29th April 2020, 09:50   #5
andyadcock
Registered User
 
andyadcock's Avatar

 
Join Date: Dec 2005
Location: UK and Occasionally St Petersburg, Russia
Posts: 18,786
How useful is leg colour?

Birds of Taiwan notes 'dark greyish' for Greenish and 'blackish brown' for Two-barred, I'd say the legs on the OP appear greyish?
__________________
Andy A

Last edited by andyadcock : Wednesday 29th April 2020 at 12:29.
andyadcock is offline  
Reply With Quote
Old Wednesday 29th April 2020, 10:35   #6
Grahame Walbridge
Registered User

 
Join Date: Jan 2015
Location: Portland
Posts: 2,586
Quote:
Originally Posted by andyadcock View Post
How useful is leg colour?

Birds of Taiwan notes 'dark greyish' for Greenish and 'blackish brown' for Tw-barred, I'd say the legs on the OP appear greyish?
Leg colour is variable across the complex Andy, and that's before factoring in lighting/photographic effects. Ticehurst describes the leg colour of plumbeitarsus as 'pale plumbeous brown or lead colour' hence the latin name, which may be good indicator though not diagnostic. As to the OP, I am struggling to make out precise leg colour from the images.

For comparisons of vocalisations see https://soundapproach.co.uk/song-and...e-netherlands/

BTW, just to be clear, I am not saying its a certain Two-barred given the apparent anomalies.

Grahame

Last edited by Grahame Walbridge : Wednesday 29th April 2020 at 10:38.
Grahame Walbridge is online now  
Reply With Quote
Old Wednesday 29th April 2020, 11:02   #7
THE_FERN
Registered User

 
Join Date: Aug 2004
Location: London
Posts: 1,533
From my state of blissful ignorance I was wondering "why isn't this greenish" too...
THE_FERN is offline  
Reply With Quote
Old Wednesday 29th April 2020, 13:25   #8
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by HouseCrow View Post
Hi
I'm a beginner at (East Asian) leaf warblers, hoping to learn and still struggling with the relatively few Japanese options, so
'presumably Two-barred' because of the calls? This could be one of the arctic complex for me (i'm a beginner remember)


Could you maybe elaborate a bit more?

thanks!
Gerben
Hi Gerben,

Chiefly calls, yes, which would eliminate any kind of Arctic Warbler.

'Presumably' Two-barred as (i) the calls fit and (ii) any other member of the Greenish Warbler complex would be vagrant here (although I have in recent years found three Greenish Warblers, two in the same woodlot as this bird!).

Steve
SteveMM is offline  
Reply With Quote
Old Wednesday 29th April 2020, 13:59   #9
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by Grahame Walbridge View Post
Leg colour is variable across the complex Andy, and that's before factoring in lighting/photographic effects. Ticehurst describes the leg colour of plumbeitarsus as 'pale plumbeous brown or lead colour' hence the latin name, which may be good indicator though not diagnostic. As to the OP, I am struggling to make out precise leg colour from the images.

For comparisons of vocalisations see https://soundapproach.co.uk/song-and...e-netherlands/

BTW, just to be clear, I am not saying its a certain Two-barred given the apparent anomalies.

Grahame
Thanks for the various links, Grahame; I'll trawl through them.

The May bird from Beidaihe does look similar in many respects, including the presence of yellows in the face and below. The attached may show leg colour a bit clearer, but I find leg colour quite variable in Phylloscs and am not sure how useful a correct determination of colour would be. They're certainly very dark, anyway.

Steve
Attached Thumbnails
Click image for larger version

Name:	Phylloscopus SP (10) - Copy.JPG
Views:	42
Size:	249.6 KB
ID:	725643  Click image for larger version

Name:	Phylloscopus SP (12) - Copy.JPG
Views:	34
Size:	297.1 KB
ID:	725644  
SteveMM is offline  
Reply With Quote
Old Thursday 30th April 2020, 08:50   #10
HouseCrow
Registered User

 
Join Date: Aug 2003
Location: netherlands
Posts: 268
thanks for clarifying that Steve, and to all elaborating others for the extra info.
Am I wrong in thinking that
-Primary projection is not visible enough to help ID
-Leg-colour seems to only rule out the light-coloured leg-species
-Song and call don't fit Arctic-complex (i understand) but don't exclude any other?
-The wingformula is not clear enough here for eliminating species? (emarginations etc)

sidequestion: is bird-ID at ebird properly verified (I think so, but I couldn't find info on it) (answered: https://ebird.org/australia/news/how...y-process-work)

cheers and good luck with this and other tough quests

gerben
__________________
observado.org records: https://bit.ly/2zb9MdW

inaturalist bird records: https://www.inaturalist.org/observat...onic_taxa=Aves

Last edited by HouseCrow : Thursday 30th April 2020 at 09:37.
HouseCrow is offline  
Reply With Quote

BF Supporter 2019 Support BirdForum With A Donation

Old Thursday 30th April 2020, 09:09   #11
andyadcock
Registered User
 
andyadcock's Avatar

 
Join Date: Dec 2005
Location: UK and Occasionally St Petersburg, Russia
Posts: 18,786
Quote:
Originally Posted by SteveMM View Post
Thanks for the various links, Grahame; I'll trawl through them.

The May bird from Beidaihe does look similar in many respects, including the presence of yellows in the face and below. The attached may show leg colour a bit clearer, but I find leg colour quite variable in Phylloscs and am not sure how useful a correct determination of colour would be. They're certainly very dark, anyway.

Steve
My unqualified leaning would be toward Greenish.
__________________
Andy A
andyadcock is offline  
Reply With Quote
Old Thursday 30th April 2020, 11:06   #12
Grahame Walbridge
Registered User

 
Join Date: Jan 2015
Location: Portland
Posts: 2,586
Quote:
Originally Posted by HouseCrow View Post
thanks for clarifying that Steve, and to all elaborating others for the extra info.
Am I wrong in thinking that
-Primary projection is not visible enough to help ID
-Leg-colour seems to only rule out the light-coloured leg-species
-Song and call don't fit Arctic-complex (i understand) but don't exclude any other?
-The wingformula is not clear enough here for eliminating species? (emarginations etc)

sidequestion: is bird-ID at ebird properly verified (I think so, but I couldn't find info on it) (answered: https://ebird.org/australia/news/how...y-process-work)

cheers and good luck with this and other tough quests

gerben
To answer a couple of your queries Gerben, its true the images are not very helpful when it comes to assessing wing formula and pp which, is no fault of Steve's I hasten to add; p1 is largely hidden beneath the wing (though clearly >pc), emarginations difficult to resolve though appears slight to p6 (image 3), while p2 falls well short of wing point (image 4) which indicates Greenish complex. Like members of the Arctic complex, differences between (Greenish) taxa are minimal and of little use when it comes to ID.

There is much overlap in bare part colouration and bill pattern for both groups and likewise, plumage. Note however, the bird lacks a pale bridge over the bill which is typical of Two-barred but a pattern shared by members of the Arctic complex which can lead to confusion.

Vocalisations point clearly to the Greenish complex but, more specifically, the trisyllabic call is (more) indicative of Two-barred. I shared the images and sound file with Wich'yanan L. (Thailand) and he concurred with the ID.

Finally, you raised a question about eBird verification. As I understand, records and images are (usually) verified at a local/national level. However, it is my experience that when trawling eBird images cases of clear misidentifications are not that unusual, and the same applies to other image databases e.g OBI, HBW. So, a word of caution when using these platforms for reference purposes.

Grahame
Grahame Walbridge is online now  
Reply With Quote
Old Thursday 30th April 2020, 11:37   #13
HouseCrow
Registered User

 
Join Date: Aug 2003
Location: netherlands
Posts: 268
Thanks Grahame,
Of course it's not bad photography, i hasten to follow you on this... I know how tough these little ones can be.. Steve's photos are miles better than my Japanese Willow Warbler of 2018.

on ebird yes, I found the official statement about it. I was not sure how well staffed it is, thanks for your view on it. I happily use all 4 sites for different purposes. Ebird is more secure than inat or obi, similar to observador.org (a Goliath and David-situation but the idea is similar)

sorry for this digression, i will try to read up on the complex, see also this old db article
https://www.academia.edu/24051066/Id...rctic_Warblers

cheers
Gerben
__________________
observado.org records: https://bit.ly/2zb9MdW

inaturalist bird records: https://www.inaturalist.org/observat...onic_taxa=Aves
HouseCrow is offline  
Reply With Quote

BF Supporter 2019 Support BirdForum With A Donation

Old Thursday 30th April 2020, 14:21   #14
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by andyadcock View Post
My unqualified leaning would be toward Greenish.
Thanks, Andy.

The somewhat 'plain-faced' look had more of a Greenish feel about it to me, too, but the trisyllabic call always suggested otherwise. With 'looks' apparently out for Two-barred, I had rather been wondering about Green!

Steve
SteveMM is offline  
Reply With Quote
Old Thursday 30th April 2020, 14:33   #15
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by Grahame Walbridge View Post
To answer a couple of your queries Gerben, its true the images are not very helpful when it comes to assessing wing formula and pp which, is no fault of Steve's I hasten to add; p1 is largely hidden beneath the wing (though clearly >pc), emarginations difficult to resolve though appears slight to p6 (image 3), while p2 falls well short of wing point (image 4) which indicates Greenish complex. Like members of the Arctic complex, differences between (Greenish) taxa are minimal and of little use when it comes to ID.

Grahame
Thanks for the detailed response here, Grahame. I was disappointed not to be able to get a clear shot of the p1 on this bird (which I like to try and capture on any Greenish-types I find), but it did seem superfluous what with having a sound recording 'n all. It can at least be seen to extend beyond the PC in some of the images in the first photo in #1.

Also, if those living in areas where Two-barreds are more plentiful consider this bird to be within acceptable variation for the species, then I think that the ID is resolved. Thanks again for all your help with it.

Steve
SteveMM is offline  
Reply With Quote
Old Monday 4th May 2020, 02:44   #16
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Sorry to drag this one up for a second time, but after reading the article Grahame linked to in #6 and looking at the sound token I recorded, this bird once again is causing me problems.

The article in #6 describes the calls of Green Warbler, and compares it to the calls of other taxa. The calls of Green are stated to be ‘W-shaped’ in the sonogram; the calls of Two-barred described only as being ‘more complex and lower-pitched’.

Looking at a few tokens on Xeno-Canto, the ‘shape’ of the call of Two-barred also looks different: an ‘N’ or ‘M-shaped’ note, with the call ‘continuing’ with a downwards stroke from the top of a vertical onset. Green, on the other hand, is ‘W-shaped’, with the call continuing with an upwards stroke from the bottom of a (near-) vertical onset. Most of the call falls below 6000Hz on Two-barred (with the central note only exceeding this in height), whereas on Green rather more elements are above 6000Hz.

Although to the ear the trisyllabic call of the Qi Gu bird sounded much ‘as Two-barred’, the sonogram suggests they are not usual (call notes are at 1.5, 2.5, and 8.0 seconds in the attached). If anything, they are a better fit for Green!

Am I misinterpreting the sonogram here somehow? Is a different interpretation open? Should I take my glasses back to the shop?

Steve
Attached Thumbnails
Click image for larger version

Name:	Calls Two-barred Warbler (XC1).jpg
Views:	31
Size:	237.5 KB
ID:	726138  Click image for larger version

Name:	Calls Green Warbler (XC1).jpg
Views:	29
Size:	231.2 KB
ID:	726139  Click image for larger version

Name:	Calls Phylloscopus SP Qi Gu (01).jpg
Views:	37
Size:	228.2 KB
ID:	726140  
SteveMM is offline  
Reply With Quote
Old Tuesday 5th May 2020, 06:46   #17
johnallcock
Registered User

 
Join Date: Feb 2007
Location: Hong Kong
Posts: 1,451
One question I would have is whether the vocalisations you have recorded are calls or introductory notes to a song. To my ear, the recording seems to include various different vocalisations, and it may not be appropriate to compare all of these to the typical call.

I sometimes encounter Two-barred singing in Hong Kong in April, shortly before they leave for the breeding grounds. The songs are not as long or complex as those published or available online from within the breeding grounds. I tend to assume that these are plumbeitarsus 'warming up' in preparation for the breeding season (it is generally assumed that most birds in HK are plumbeitarsus)

If these are songs, one taxon that may need to be considered is obscuratus. The sound approach page linked earlier by Grahame includes sonograms of obscuratus which show that the song is simpler than plumbeitarsus, and also that the elements of the song have a 'W' structure similar to your description for your bird and for Green.

I suspect that your bird is plumbeitarsus, but I'm not entirely sure. I find this complex very confusing. Most of the existing literature focuses on the differences between the most distinct taxa (viridanus and plumbeitarsus), which I think lead to obscuratus (and possibly trochiloides) being overlooked so that their distribution and movements are currently not properly known.
johnallcock is offline  
Reply With Quote
Old Tuesday 5th May 2020, 14:05   #18
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by johnallcock View Post
One question I would have is whether the vocalisations you have recorded are calls or introductory notes to a song. To my ear, the recording seems to include various different vocalisations, and it may not be appropriate to compare all of these to the typical call.

I sometimes encounter Two-barred singing in Hong Kong in April, shortly before they leave for the breeding grounds. The songs are not as long or complex as those published or available online from within the breeding grounds. I tend to assume that these are plumbeitarsus 'warming up' in preparation for the breeding season (it is generally assumed that most birds in HK are plumbeitarsus)

If these are songs, one taxon that may need to be considered is obscuratus. The sound approach page linked earlier by Grahame includes sonograms of obscuratus which show that the song is simpler than plumbeitarsus, and also that the elements of the song have a 'W' structure similar to your description for your bird and for Green.

I suspect that your bird is plumbeitarsus, but I'm not entirely sure. I find this complex very confusing. Most of the existing literature focuses on the differences between the most distinct taxa (viridanus and plumbeitarsus), which I think lead to obscuratus (and possibly trochiloides) being overlooked so that their distribution and movements are currently not properly known.
Thanks, John. You make vaild points as always.

Out of interest, do you see many spring Two-barreds in Hong Kong that lack the upper wingbar? As I said in #1, I have only seen autumn individuals before, and these have always sported two clear wingbars.

Steve
SteveMM is offline  
Reply With Quote
Old Friday 8th May 2020, 13:58   #19
johnallcock
Registered User

 
Join Date: Feb 2007
Location: Hong Kong
Posts: 1,451
Quote:
Originally Posted by SteveMM View Post
Thanks, John. You make vaild points as always.

Out of interest, do you see many spring Two-barreds in Hong Kong that lack the upper wingbar? As I said in #1, I have only seen autumn individuals before, and these have always sported two clear wingbars.

Steve
Unfortunately I also tend not to see so many this late in the spring. I know that the wing bars in late winter are often quite worn and the upper wing bar is not always visible. I don't think these are replaced during the pre-breeding body moult but I'm not entirely sure (Grahame may have a better idea).

Having said that, I did see one this morning (singing and calling to confirm ID). Unfortunately it wasn't great views (a bit distant and in a treetop) but I did try to pay attention following this conversation. As far as I could tell, it seemed fairly similar to this bird - I couldn't make out an obvious MC wing bar (there may have been one but only faint) and the GS wing bar seemed a little more obvious than on your bird, but not as broad and obvious as I'd expect in autumn.
johnallcock is offline  
Reply With Quote
Old Friday 8th May 2020, 18:43   #20
Grahame Walbridge
Registered User

 
Join Date: Jan 2015
Location: Portland
Posts: 2,586
Quote:
Originally Posted by johnallcock View Post
Unfortunately I also tend not to see so many this late in the spring. I know that the wing bars in late winter are often quite worn and the upper wing bar is not always visible. I don't think these are replaced during the pre-breeding body moult but I'm not entirely sure (Grahame may have a better idea).
Moult strategy of plumbeitarsus should be pretty much identical to that of viridanus (Ticehurst) for which see Hellstrom https://ringersdigiguide.ottenby.se/...-trochiloides/ a complete pre-nuptial moult is undertaken on winter quarters Feb-late Apr. Once pre-nuptial moult is complete ageing is not possible.

Shirihai & Svensson (2018) give a slightly more extensive post-breeding/post juvenile (summer) moult which involves (some) wing coverts.

Grahame

Last edited by Grahame Walbridge : Saturday 9th May 2020 at 03:04.
Grahame Walbridge is online now  
Reply With Quote
Old Saturday 9th May 2020, 06:48   #21
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
I received the attached JPEG from Roy Slaterus this morning (who has kindly given permission for me to post it here). Roy is the author of the article on The Sound Approach website linked to in #6. I think this makes him perhaps the best person to look at this bird, and he has been kind enough to do so over the last couple of days.

The unusual calls I highlighted at 1.5, 2.5, and 8.0 seconds in #16 are treated as calls, just atypical ones. Calls at such high frequencies are given by Two-barred Warbler, hence these vocalisations fall within the range of that species.

I've had some very productive exchanges about this bird (both with Roy and here on BirdForum). It seems to be one that is to some extent at extremes (both in terms of its outward morphology and its vocalisations), but ultimately one that is 'just a Two-barred'!

Steve
Attached Thumbnails
Click image for larger version

Name:	taiwanwarbler - Copy.jpg
Views:	64
Size:	429.0 KB
ID:	726667  

Last edited by SteveMM : Saturday 9th May 2020 at 07:00.
SteveMM is offline  
Reply With Quote
Old Saturday 9th May 2020, 07:47   #22
johnallcock
Registered User

 
Join Date: Feb 2007
Location: Hong Kong
Posts: 1,451
Thanks for an interesting discussion on this bird. Very useful.
johnallcock is offline  
Reply With Quote
Old Saturday 9th May 2020, 10:21   #23
SteveMM
Registered User

 
Join Date: Jan 2015
Location: Tainan, Taiwan
Posts: 411
Quote:
Originally Posted by johnallcock View Post
Thanks for an interesting discussion on this bird. Very useful.
Yes, thanks John. Although this bird didn't quite live up to the promise I at one point thought it might have, discussion of it has nevertheless been educational and rewarding.

Steve
SteveMM is offline  
Reply With Quote
Advertisement
Reply


Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Phylloscopus ssp? (Portugal 12/01/2020) Marcio Cachapela Bird Identification Q&A 2 Tuesday 14th January 2020 11:05
Swinhoe's Snipe? Tainan County, Taiwan August SteveMM Bird Identification Q&A 5 Thursday 23rd August 2018 11:40
Sand Martins, Tainan County, Taiwan SteveMM Bird Identification Q&A 1 Saturday 23rd September 2017 14:59
Another Large Gull SP., Tainan County, Taiwan: taimyrensis or mongolicus? SteveMM Bird Identification Q&A 8 Thursday 16th February 2017 00:12
Another Large Gull SP., Tainan County, Taiwan: vegae or something else? SteveMM Bird Identification Q&A 6 Monday 13th February 2017 11:00



Fatbirder's Top 1000 Birding Websites

Help support BirdForum

Page generated in 0.28812194 seconds with 36 queries
All times are GMT. The time now is 07:53.