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Eurasian or American Wigeon, at Mai Po (Hong Kong)? (2 Viewers)

MKinHK

Mike Kilburn
Hong Kong
Very interested to hear your thoughts on this odd-looking wigeon sp. filmed via my phonescoping set-up yesterday at Mai Po. It was was in with a few score of Eurasian Wigeons and showing in bright sunlight. Unfortunately the video has a rather dusty cast, which mutes the differences between grey and brown. For the record there are a few records of American Wigeon in Hong Kong and more records of hybrid males, so I'm aware that it may not be possible to be conclusive.

Thanks in advance for any insights.


Cheers
Mike
 

Jon.Bryant

Active member
Hi Mike,

Hopefully you remember me - I used to be in Hong Kong in the early 90's and we used to go birding together sometimes. Great to see you are still birding the area.

It is a long time ago since I have seen American Wigeon, but it doesn't look right to me - that said in 'The Helm Guide to Bird Identification' (Vinicombe, Harris and Tucker) it mentions the need to see the auxiliaries (white in American and grey in Eurasian) as both species show considerable variation and overlap in other ID features (and of course there is also the hybrid problem).

Not sure how obvious it was in the field, but the left side of the head head seems to show a stronger pattern ghosting male American. The breast pattern also make me think this is a first-year male (but I am no expert). If this is the case, it may be one to watch out for as the winter progresses and it becomes more adult like (except for the upper wing coverts) - then all you need to do is make it raise it's wings while side on, so you can see it's arm-pit and the all important auxiliaries!

Without the auxiliaries, I think it has to go down as 'Wigeon Sp'.

Cheers

Jon
 

MKinHK

Mike Kilburn
Hong Kong
Hi Jon - great to hear from you and to hear you're still birding!

I still remember doing a Christmas bird count with you at Mai Po in 93 or 94 and seeing Chestnut Bittern and 2 Otters at the Scrape!

Also delighted to find some interest in the possibility that this might be American Wigeon! I have been wondering about immature male on the basis of that ghosted facial pattern. Definitely one to watch in the next few weeks - if I can find it again amongst 2-3000 Wigeon!

Cheers
Mike
 

SteveClifton

Well-known member
I think your bird is a European Wigeon, albeit a slightly odd-coloured individual.

When researching female American Wigeon ID earlier this autumn, I came across a feature that is potentially quite useful, and is visible in your video.

The greater covert pattern of female European Wigeon is typically grey-brown in the centre with thin white fringes. Quite different from female American, which has a white or pale grey base with conspicuous black tips (see the attached image-sorry, but can't recall where I sourced it).

My other image shows a female European Wigeon in the front (in the UK) and what I presume is an immature drake European Wigeon behind it. Greater coverts are arrowed. My presumption about the rear bird being an immature drake is based on the greater covert pattern looking the same as an adult drake European (and very similar to female American!), but confusingly the bird showed no other signs that it was an immature drake. For example, imm drakes usually have obvious grey vermiculated body feathers which start to show through as winter progresses. I still have no reason however, to think that it isn't a EW, as it looks like one in most other respects.

I found it very hard to find good ID material on this feature, but in the little material that I could source, female AW typically shows a straighter line dividing the pale base and black tip to the greater coverts. I also noticed that the two inner-most visible greater coverts on my presumed immature drake are all pale (lacking the black tip) which matches the one other image I could find of a definite immature drake European Wigeon.

Sorry for the long-winded reply, but your bird (inset, and frozen at 1 min 24 seconds) looks most like my female European Wigeon in its greater covert pattern. Perhaps not a definitive answer but it might offer an avenue for further research...?
 

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Jon.Bryant

Active member
Steve,

Interesting possible ID feature. Checking some of my references, both the Helm 'Bird Identification' guide and 'Advanced Bird ID Handbook' mention that the coverts of American Wigeon tend to be paler than Eurasian Wigeon. The later reference also mentions that this is because the coverts have a white base and wider pale fringes, but also mentions the dark tip to the greater coverts, without being specific about whether this is an ID feature.

I think that possibly care is needed when looking at the greater coverts which are generally concealed in the closed wing. Looking at photographs of female American Wigeon open wings, I have found one photo where the inner 2 greater coverts do not appear pale with a dark tip, but dark grey with a narrow pale margin. As the inner greater coverts are the ones most likely to be exposed on the closed wing, I think that the true pattern on the feathers could be misinterpreted by looking at one or two feathers. On your photo of the bird with the black tips to the greater coverts, I note that the top feather although pale does not show the dark tip. The lower bird shows the three innermost greater coverts.

In the bottom two images in this link American Wigeon (tsuru-bird.net (apparently of American Wigeons), the coverts look pale with wide fringes, but the dark tips are not apparent, even though one bird shows three and a bit of a fourth greater covert. The pale fringes to the coverts in the bottom bird are also noticeable thinner than the bird above, so some variation to the feathers.

To try to get a details description of the feathers I looked at 'Birds of the Western Palearctic' plumage section (an old reference, but detailed plumage descriptions should not change over time). For Eurasian Wigeon adult female it states 'Upper wing-coverts dark grey-brown, contrastingly edged white at tips, occasionally faintly barred and laterally suffused buff. Outer web of greater coverts tipped black (narrower than adult ♂), narrowly bordered white subterminally, often edged white at tip.' Interestingly for immature male it states 'Greater upper wing-coverts grey, outer webs with tip black, often narrowly bordered white' and for immature female 'Greater upper wing-coverts usually without dark blotch on white tip of outer web, but sometimes some black freckling'. I therefore wonder if the absence of the dark tip to the feathers is more of an ageing criteria for immature females?

That said, unless the image ifs effected by the harsh lighting, the video grab shows that the Mai Po bird has quite dark grey coverts with thin pale fringes, so more of a Eurasian Wigeon feature.
 

SteveClifton

Well-known member
Jon, thanks for getting back to me, and for the additional references and links.

For clarity, the greater coverts of female American Wigeon is mentioned as an ID feature in the first edition of Advanced Bird ID Guide, though it's possible that as a reliable ID feature its importance might have been revised in the new edition (which I don't have). That might also explain why older guides don't mention it, as new ID features are constantly being discovered and tested. I'm not sure to what extent this feature has been tested, but I mentioned it as a possible clue in the absence of better views of other features such as the axiliaries.

You are right to be cautious about the amount of black showing on the tips of the greater coverts, and as you pointed out, the inner most feathers (and hence most visible on the folded wing) probably have the least amount of black at the tips. It's also interesting to note that from the description of female Eurasian Wigeon in BWP that they too can have the black tips-that was a surprise to me, and I hadn't noticed it in any of the photos I saw when researching a couple of months ago. I also agree that it might be affected by age as well as sex, so clearly we could benefit from better information on this feature...

Looking closely at the two female AW in the link you attached, they do both show some thin black tips on the greater coverts. On one they are little more than a thin black fringe, and on the other they are a little broader and restricted to the outer web (I have arrowed them on the attached image). Who knows how much more extensive they might be on the other G Covs that we can't see? I have no reason to doubt that they are both American Wigeons by the way. Both have heavily flecked heads, and show another ID feature of female AW-the grey innermost secondary. One is noticeably darker grey, and the other light grey. On European Wigeon this should be white (or off white as I have seen personally in the field). Note that on the Mai Po wigeon the inner secondary looks quite pale or off white, but there isn't much of it showing to get a clear view.

We might never get a solid ID on the subject bird in post #1, but hopefully we will have learned something about wigeon ID in the process!
 

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SteveClifton

Well-known member
Further to the above, I found this article online.

I've copied the relevant sections on covert patterns of both species, highlighted in different colours, and it would appear that the two females at the bottom of John's link above (screenshots in post 9) fit the description for immature female American Wigeon.

My bird however (the presumed immature drake Eurasian) doesn't exactly fit the description for immature drake Eurasian based on the description in the article! The black tips could perhaps be described as more 'irregular' (with a more 'saw-toothed' upper edge) when compared with typical adult female AW, but they are still quite extensive. Not sure what to make of that ???
 

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Joern Lehmhus

Well-known member
I suspect there are gradual differences with a lot of individual variation rather than this being a clearcut difference for all birds? Some individuals may be closer to the other species than others.
 

Jon.Bryant

Active member
Hi Steve,

I have found it really hard to find good images of Eurasian Wigeon female upperwing. The image below is labelled as Eurasian Wigeon, and shows a white inner secondary and some colour in the speculum, so the ID and age are both presumably correct. On this bird there are distinct black tips to the greater coverts feathers, but the bases of the feathers are similar to the other coverts, so no white greater covert wing bar mentioned in the article you posted. 1609332022897.png
The second image is identified as a photo of an American Wigeon female in the University of Puget Sound collection, but looks almost like a painting to me! Anyway, on this bird I can see that the bases to the greater coverts are clearly paler than the other coverts (with a fairly wide white band) and that the black tips are more extensive. The inner secondary is also grey.
American Wigeon Female.jpeg

I am still not clear whether the various articles are flagging up the pale greater covert bar, running along the base of the greater coverts, or are making reference to the dark tips. Assuming the tips are consistently more extensive and darker in any cases (as they are in the attachments), the pale base would be further accentuated by the dark tips in American Wigeon.

I hadn't noticed the fine black tips to the greater coverts in the images in the link I posted, and which you kindly highlighted. My question here is whether theses are very fine black terminal fringe or are a shadow effect (I note that one of the tertials also seems to show a very thin fringe. which raised my concern). That said, the article that you posted refers to a pale sub-terminal band and thin black terminal band in immature female American Wigeon, so perhaps this is what we are seeing in the images.

My wife's hobby is photography, so looks like I will need to give her a mission to photograph Wigeon upper wings in future!

As you say, it is good to learn something about Wigeon ID and I will be looking more critically at these feathers in future.
 

Jon.Bryant

Active member
Hmmm, just thought of a ringers guide to check - 'Identification Guide to Birds in The Hand'. It covers Eurasian Wigeon, but American Wigeon only in passing.

For Eurasian Wigeon female it states 'GC typically grey with black and white at the tip (strong variations...' and references a figure showing various patterns some with black tips and some not.

For juvenile and first-winter female it also adds that the feathers often show no black-tip.

The book states the American Wigeon female has 'centre of GC rather pale, paler that MC, GC with a lot of white on the outer web, and a broad black tip (but sometimes as A.penelope in 1YF)'. For Eurasian Wigeon it says 'centre of GC, rather dark, of same colour as MC, F + 1Y: less white on outer web, dark tip rather thin and duller.'

This again seems to suggest that the pale base to to the greater coverts is of interest, and this is also appears the case when I look at flight photos of American Wigeon, which consistently show a clear white upper wing bar formed by the bases to the GCs. Unless the wing is partially opened, I am not sure how much of the tip and the base can be seen of each GC - the open wing photos seem to show a much longer feather than visible in the closed wing photos. If only the tip can generally be seen in the closed wing, this may limit the use of the white wing bar as a feature for birds on the ground or water.
 

SteveClifton

Well-known member
Well Jon I'm thoroughly beat by these wigeon! Too much variation and every question answered seemingly generates another that can't be!
The female Eurasian Wigeon wing above (in post 12) throws a spanner in the works with everything I thought I understood, but perhaps if it really is one then it isn't so different to the bird I thought was an immature drake Eurasian Wigeon in post 6. Perhaps both are females? but why so different? or perhaps some of the birds we've been sourcing online are mis-labelled?
 
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MKinHK

Mike Kilburn
Hong Kong
Many thanks for the discussion and insight gents. the further I read the more complicated it all becomes!

I've twice been back but not connected with this bird again.

Cheers
Mike
 

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