Interesting aythya: Songdo, November 13-17

On November 13th and 14th at Songdo Lagoon, aka Namdong Reservoir, Incheon, a curious aythya  duck was seen and photographed (below) by Mr Spike Millington and John Clark. It was described as showing a prominent white wing-bar in flight,  and was identified as a first-winter male Baer’s Pochard. I have sharpened the image slightly.

Image 1A

On November 17th at the same site, a duck – presumed to be the same individual- was photographed by Dr Shim, Kyu-Sik (below).

Image 2A: November 17th.

Image 2B.

Image 2C

Image 2D.

Opinions and discussion as to the identity of this intriguing bird are welcomed!

 

6 comments on “Interesting aythya: Songdo, November 13-17

  1. I am happy to see these photos. I guess the issue is whether there are any Ferruginous Duck genes in there. If so, they would be expressed in the colour of the head and back which are dark chestnut brown and maybe less white on the flanks that typical (adult) Baer’s. There is certainly no hint of green on the head, which is why we suggested first winter, but maybe you would expect to see some by now. Most of the tufted ducks present were in eclipse-type plumage. Let’s hope the bird stays around and we can see if the plumage changes

  2. A point about structure–photos of Baer’s often show a smoothly flattened beak-to-crown progression–a bit like a rounded-off canvasback– while this bird suggests some overall blockiness and a steep forehead–a characteristic that may support your Ferruginous idea.
    All that said, I’d dearly like to know that a Baer’s was gracing Songdo’s lagoon!

  3. Are there any more, larger-size images of the bird in Image 1A? And do the images show one, two or even three different individuals?

    No doubt, aythya can be tricky to identify at this time of the year , and it might be helpful to break down the possibilities a little?

    Age:
    If this / any of these images were of Critically Endangered Baer’s Pochard then the pale iris-colour would indicate a male. Male Baer’s in nuptial (=breeding) plumage have been seen as early as early August (in Baer’s species account in Ducks, Geese and Swans). Therefore, very probably none of the images (taken in mid-November) show an adult male still in eclipse. Juveniles (male and female) are more female-like, initially with brown eye-colour and a “russet-brown abdomen” (from the same source). None of the images show a duck with a brown iris and a russet-brown abdomen (although the bird in images 2A and 2B does have warm brown undertail coverts). Therefore none of the images show a Juvenile Baer’s.

    Although some aythya (eg Greater Scaup) might be ageable as First-winter (based on a combination of subtle plumage and bare parts differences from adults, and by the timing of moult into an adult-type plumage) I have so far been unable to find any such First-winter plumage described for the rather poorly-known Baer’s. Do Baer’s actually have such a plumage?

    Plumage:
    Four species of “yellow-eyed” aythya have been adequately documented in the ROK: Baer’s, Ferruginous, Tufted Duck and Greater Scaup.

    There seem to be several things wrong with the plumage of this/these bird(s) for Baer’s: the limited extent of white on the flanks; the lack of striping on the flanks (dark lines across the white foreflank patch shown by most, perhaps all Baer’s); the lack of clear division between the very warm-toned breast and the flanks; and the apparently darkish rear end. Baer’s, of all ages at this time of year, have white undertail coverts. The bird(s) in the image has/have dark undertail coverts.

    As the bird(s) in Images 1 and 2 are not Baer’s, the question then becomes what are they? The bird in Images 2A-D) looks too big, too heavy-billed and too warm-toned for a Tufted. Especially in Images 2 A-C, the large bill looks good for Baer’s, but in combination several of the plumage features seem better for a Juvenile > First-winter male Greater Scaup, including: yellowish iris; mottled breast; hint of pale coming through on the mantle (easiest to see on Image 2 B); limited white showing on flanks (most near water-line); and dark/darkish undertail coverts. The bill also looks about right for Greater Scaup, being obviously heavy and long, with a small dark nail.

    I had thought, based on a couple of Dr. Shim’s images sent separately in an earlier mail, that the bird in 2Dmight well have some Ferruginous influence (most especially as the bird looked so warm-plumaged, with lots of russet, and there seemed to be obvious paler grey on the bill above the dark nail). However, I am struggling to see much obvious Ferruginous infuence in these small-sized images, especially as the warmest plumage tones in eg Images 2A and 2B are clearly still much duller than the head colour of the Common Pochard.

    Hope that the above helps?

  4. Very useful comments from Robin and Dr Moores. I suspect all photos are of the same bird (the first was quite distant). I agree the bird, if BP, is a male and also wonder if this first winter plumage exists, and if it would be present in November (hence my comment about the lack of full plumage Tufteds at the site). It is illustrated in at least one field guide. BTW the bird had strongly marked white under tail coverts (I guess not visible when the tail is held down in photos). I also agree that the white flanks and barring characteristic of adult BP are much more limited here (though barring was present), but maybe that is to do with this plumage.

    Structurally, it doesn’t seem like Greater Scaup, which were present on site for comparison (though not associating with this bird). I agree with Dr Moores about the lack of Ferruginous influence (see link to photo of Dalian bird with FD, below). I still suspect (and am hoping for) a regular Baer’s.

    Interestingly a very similar bird was seen at Dalian China yesterday

    http://www.birdskoreablog.org/wp-content/uploads/2012/11/BaersDalianNov27.jpg

    http://www.birdskoreablog.org/wp-content/uploads/2012/11/BaersAndFerrugDalianNov27.jpg

    Spike

  5. Spike and I first saw the bird in image 1A at very close range in the channel flowing out of the reservoir on Tuesday Nov 13th. Unfortunately we did not have a camera with us. We identified it as a first-winter male BP – first-winter because the head was brownish, without a green sheen, and male because of the pale eye. It did have prominent white under tail coverts when seen from behind – in fact it was this feature at 400m range which first caught our attention. We also noted the tiny black nail on the large blue grey bill.

    I looked for the bird again on Nov 14th and finally located it after three hours when it swam out of a reed-bed in the middle of the reservoir. I watched it for half an hour through 20-60 Swarovski scope and also obtained picture 1A. I saw it in flight, when it showed an extensive bright white wing bar of the type only shown by BP and Ferruginous (and presumably hybrids with genes from these two sp). I left 100% happy with it being a fw male BP.

    I think the bird in images 2A-2D is the same bird as 1A. Contra what Nial can see from the pics – it does have white undertail coverts. There were at least 13 Greater Scaup on the reservoir on Nov 14th and all of these were female/juveniles types except for one which was an obvious first-winter male – generally female in appearance but with a clean head (without pale ear patches) and with pale vermiculations starting to appear on the back. These birds moult into full adult males by the end of the winter, a feature shown by other diving duck such as Goldeneye and Goosander as well. I see no reason why Baer’s Pochard can’t have a similar plumage progression. As Spike has said, hopefully the bird will remain long enough for changes in its plumage to be observed.

  6. It is helpful to hear more about the original sighting and field impressions: thank you. Are there any other images of the bird at all from the original sighting that can be shared please? And is the bird still there, perhaps?

    It is also great to see the images from Dalian, though respectfully, would you not agree that they show most of the necessary features that make identification as a Baer’s pretty straightforward? These include structure; much white on the flanks above the water line (coming up highest on the foreflank); hint of striping to the upper edge of the white; obvious, extensive dark-framed white undertail coverts; solidly dark upperparts; and mahogany tones on the breast. There is nothing in the images to ring alarm bells (apart from it being so close to a Ferruginous!). All of the images from Song Do (not the field description – the images) do ring bells for me and perhaps for others (?) – some of the images more than others (still seems perhaps two or even three different birds shown).

    A dull-headed Baer’s in Dalian (a First-winter? Would seem to be the most likely age for it: excellent!) shows these features clearly at this time of year. The question then becomes: do the Song Do images show the same features? I can see that the bill looks good for a Baer’s. The other features?

    Finally from me, relevant or completely irrelevant to this discussion, for those who have the book, there is an interesting section on aythya hybrids in the old Madge and Burn identification guide, “Wildfowl” (on Pp. 244-245). The first Ferruginous Duck recorded here in the ROK (on World Wetlands Day, in 2002: yup, on 02/02/02!), was displaying to a Baer’s, and in the past decade there have been at least a couple of Baer’s-like birds that did not feel quite right, and one Ferruginous type with green sheen on the head (for last, see: http://www.birdskorea.org/Birds/Birdnews/BK-BN-birdnews-2007-03.shtml). It seems rather likely that these two species do hybridise on occasion (hence the sense of alarm at the Dalian image!).

    Thanks once more for the description and am really looking forward to seeing more news and images from Song Do!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.