White-headed Stilt ? central Thailand (1 Viewer)

[S_Man]

Hello, looking at my Robson's Birds of SE Asia, this couple look like White-headed Stilts, but would this be out of range in Bueng Boraphet ?

If Black-winged, any key to id ?

 

[foresttwitcher]

The black partial collar on the back of the neck of the right-hand bird would point to White-headed (Australian / Pied) Stilt - the neck would be all white on Black-winged Stilt. I presume the left-hand bird is an immature given the colouring.

 

[S_Man]

The black partial collar on the back of the neck of the right-hand bird would point to White-headed (Australian / Pied) Stilt - the neck would be all white on Black-winged Stilt. I presume the left-hand bird is an immature given the colouring.

Thanks. That was my idea too. Also the brownish bird may be a young female ?

I had some doubts after looking at Thailand's birdlists, and even the very few range maps I can find on the web for this species.

My Robson's book mentions sightings in Cochinchina, which is today's Cambodia and south Vietnam, so that's only a few hours of flight for a bird !

Birdlife's data (from xenocanto website) extends from Sri Lanka to north Philippines, but nothing in SE Asia.

I don't have Birds of Thailand, neither Robson nor Lekagul's, which have maps...

 

[RafaelMatias]

They are Black-winged Stilts in my opinion. The black on the back of the neck of the adult is within normal variation of the species. See some examples from Portugal here:
#1
#2
#3
#4

The brown mantled bird is a 1st winter.

Australian Stilt would have a more extensive black patch, and thicker around the neck sides. Voice would be a better way to identify with certainty such a vagrant in Thailand. This species is not included in the book you mention (the one with maps), and there seem to be no records of the species yet in the country.

Cheers

 

[foresttwitcher]

Thanks for that Rafael, I have not seen a Black-winged with so much black on the neck (& have not seen the other species at all) but the photos you linked show otherwise so I withdraw my initial comments.

I really ought to stop putting up ID posts!

 

[RafaelMatias]

I really ought to stop putting up ID posts!

No, please keep posting them! I'm sure everyone here finds them interesting!

 

[S_Man]

Thanks for these examples

Great info, I had never seen this black neck patch here in Europe nor in Thailand, it's a bit tricky !

So White-headed Stilt with more extensive black patch, thicker around the neck sides, and maybe the white space between the neck patch and the black upper-mantle a bit narrower ?

 

[Southern Frogmouth]

Great info, I had never seen this black neck patch here in Europe nor in Thailand, it's a bit tricky !

So White-headed Stilt with more extensive black patch, thicker around the neck sides, and maybe the white space between the neck patch and the black upper-mantle a bit narrower ?

Here are a few photos of White-headed Stilts taken near Melbourne and they show the effect posture and individual variation can have on the neck patches so it really isn't easy in my opinion.

Cheers

Roy

 

[S_Man]

Also if they are Black-winged, they may be related, as both birds have the same unusual neck pattern, if not colour.

To make things more complex, I see that White-headed is/was sometimes described as a subspecies of Black-winged.

 

[RafaelMatias]

As Roy says, identifying out of range Stilts is really not very simple, and obtaining good sound recordings would be as important as studying plumage of a suspect bird.
Still, W-h Stilts seem to be subject to less variation than B-winged, with the white of the head purer, and the black on the neck clearly more extensive (although this would need to be carefully evaluated, with the bird in a range of postures, as Roy also mentioned). I think you're right on the field characters you mention on post #7 (including narrower white collar on hindneck). I've never seen both "species" (taxa) together, and I doubt many people have (except as museum skins), but to my eyes the fuller "black mane" as described in literature makes it look different even from the most extreme B-winged.

Taxonomy is complex, and depending on the authority W-headed Stilt is treated as a subspecies of Black-winged (Himantopus himantopus leucocephalus) or a separate species (Himantopus leucocephalus). BWP Alive (who treat it as a subspecies, following BirdLife) says the following:

Taxonomy: Charadrius Himantopus
Linnaeus
, 1758, southern Europe
.

Closely related to H. novaezelandiae, with which known to hybridize and which is sometimes considered conspecific. Races often considered to warrant recognition of 2–5 distinct species. Races can be split into three groups (nominate; “pied” race leucocephalus; and “black-necked” races knudseni, mexicanus and melanurus); four groups (as preceding one, but with melanurus separated out as a full species); or five monotypic groups (as indicated here, below). One recent author (Livezey, B.C. (2010) Phylogenetics of modern shorebirds (Charadriiformes) based on phenotypic evidence: analysis and discussion. Zool. J. Linn. Soc. 160(3): 567–618.) treated each of the forms himantopus, leucocephalus, knudseni and mexicanus (but not, puzzlingly, melanurus) as a separate species, but provided no supporting evidence. Patterns of differentiation on the head are notable but thematically recurrent (e.g. similar between knudseni and mexicanus, and between leucocephalus and melanurus), and typical calls of nominate and leucocephalus apparently differ, latter giving lower-pitched, shorter notes (Bakewell, D.N. (2012) What is the status of White-headed Stilt Himantopus (himantopus) leucocephalus in the Oriental region? BirdingASIA 17: 14–16.). With the (current) limited availability of vocal evidence indicating differences between taxa, however, the case for treating this complex as anything but a single species with variations in the amount and distribution of black on the head and neck is hard to make. Geographical variation also claimed in S Africa and Sri Lanka, in respective forms meridionalis and ceylonensis, but both exhibit considerable overlap with other populations of nominate himantopus. Five subspecies normally recognized.

Subspecies and Distribution• H. h. himantopus (Linnaeus, 1758) – Black-winged Stilt – France and Iberia S to sub-Saharan Africa and Madagascar, and E to C Asia and NC China, Indian Subcontinent (including Sri Lanka), Indochina and Taiwan; winters S to Africa, Middle East and S & SE Asia to Borneo and Philippines.
• H. h. leucocephalus Gould, 1837 – Pied Stilt – S Sumatra and Java E to New Guinea, and S to Australia, Tasmania and New Zealand; winters N to Philippines, Greater Sundas and Sulawesi, and as far as Sri Lanka.
• H. h. knudseni Stejneger, 1887 – Hawaiian Stilt – Hawaiian Is.
• H. h. mexicanus (Statius Müller, 1776) – Black-necked Stilt – W & S USA through Central America and West Indies to Colombia, N Venezuela, Galapagos, E Ecuador to SW Peru, and NE Brazil.
• H. h. melanurus Vieillot, 1817 – White-backed Stilt – Chile and EC Peru through Bolivia and Paraguay to SE Brazil, and S to SC Argentina.

On the other hand, IOC considers it as a separate species. Note also the above reference on the status of W-headed Stilt in the Oriental region.
Additionally, I just found this very interesting discussion page, where many of the above mentioned issues are developed in detail, including the calls/voice issue: https://ebonph.wordpress.com/2014/03/01/ask-the-experts-stilt-identification/

I hope this helps.

 

[S_Man]

Thanks again. I mentioned taxonomy because I was wondering if this could be some form of hybridization between both species/subspecies, and in your ebon website link, C. Perez is asking the same question:

Another possibility is that it is the result of hybridisation in areas where the two taxa have now met. In view of the apparent expansion in the breeding ranges of both taxa, hybridisation may be increasing. Whatever the case, I suggest that there is sufficient evidence for the existence of Black-winged Stilts showing White-headed Stilt plumage characteristics for extra-limital sightings of apparent White-headed Stilts to be treated with great caution, particularly if such birds occur singly and in the company of Black-winged Stilts during the northern winter. Special attention should be given to the extent of the nuchal mane, and whether the rest of the head is in fact pure white, with no darker flecking or shading.”

As both forms are expanding, and both forms would be now breeding in north Sumatra (First breeding records of Black-winged Stilt Himantopus Himantopus Himantopus in Indonesia), not so far from peninsular Malaysia, where this 2nd link shows several of those "White-headed" type Black-winged Stilts !

Well, it's just a matter of naming this bird correctly, and now I know it's not worth signaling this sighting to some authority.