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Big Gulls in Taiwan (3 Viewers)

Most birds around now are taimyrensis. The usual variation in bill and head markings, but more consistency in P10 today! The last bird is a remarkably dark-eyed individual.
 

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One of today's first-winters left me feeling a bit confused. I can only assume that the bird is taimyrensis as the outermost greater coverts appear dark, the 'hand' is dark, and only taimyrensis should be replacing greater coverts right now (it dropped one as it was standing there). However, it is comfortably the most intricately-patterned individual of the spring so far! (The last photo is of a more typical first-winter taimyrensis, also taken today.)
 

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And a second-winter which also left me scratching my head. I assume this to be a second-winter due to the complete tail band and black secondaries. The distribution of grey above is as taimyrensis of that age, but this bird has a very mongolicus-like pale 'window'. Still, I assume it to be much better for taimyrensis (if aged correctly).
 

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The fun and weirdness was all at my inland site, where the composition of the gull flock seemed to have changed since the last time I looked (very few adult mongolicus). Viewing there is usually challenging as you face south, and if the sun is out it gets awkward!

The first birds I clapped eyes on were the two in the first photo.

The sitting bird is still growing its P10 and has a dull green bill. It also has something 'a bit thayeri' going on in P7. I can only assume from the timing of moult, the pale saddle, and the dull bare parts that it is vegae, but where are all the head streaks?

The standing bird has the beady-eyed look and bright bill of a mongolicus. However, the saddle is a bit on the dark side and the bill much longer than any mongolicus so far. I did manage to get this one in flight when it left, and still it did not seem typical. Pro-mongolicus features were the dark eye, crisp-looking plumage, pale 'hand' (from below), and the pattern of P10. However, pro-taimyrensis features were the lack of a mirror on P9 and the fairly narrow trailing edge. Not sure which one of these I prefer, really.


The standing bird, which is the one in the flight pics, can't be a mongolicus or vegae with those bright Yellow legs. With that quite long and rectangular ending tongue I doubt it's a taimyrensis. For me it's a barabensis
 
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Back at my inland site, the light was surprisingly good late afternoon. The presumed vegae from #77 above was once more present and not just sleeping this time. On the spread wing, the tip to P10 and the longish and uneven-edged tongue are out for some kind of pale-end taimyrensis, as is the rather broad trailing edge. The late moult and dull bill are also not right for mongolicus. All of the above do fit vegae, though, so it does look like this is an adult which has simply completed its body moult early.


I don't know if this one's a vegae, head and bill jizz are not quite good imo. Why not a retarded mongolicus?
 
The standing bird, which is the one in the flight pics, can't be a mongolicus or vegae with those bright Yellow legs. With that quite long and rectangular ending tongue I doubt it's a taimyrensis. For me it's a barabensis

Thanks, Alex. Your comments are much appreciated.

There is something 'different' about this individual, though hard to say precisely what. I thought about barabensis (without really knowing what that meant), but seemed to recall that that form should have worn apical spots by March. Would that not be a problem for this individual?

Also, I found a second individual (same day) with a rectangular-ending tongue, a type that I used to think had a very good chance of being barabensis on account of all the black in the bill. However, after finding so many adult taimyrensis with black bill markings, I quite gave up looking for this form. At that time, though, I had no idea about the underside of P10. Is a rectangular-ending tongue a strong feature of barabensis?

Attached: 2 x Indivdual #77; 1 x taimyrensis with rectangular-ending P10.
 

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I don't know if this one's a vegae, head and bill jizz are not quite good imo. Why not a retarded mongolicus?

No real answer for you there, but I still find myself preferring vegae. Looking back through the mongolicus above, they too have rather square-ended tongues on the underside of P10, but this one has a more wavy/ragged-edged look to it. Also (although I find this measure more confusing than helpful), black on the primaries only reaches to the outer web of P5 (typically to P4 on mongolicus). The eye (though dark) also looks a bit big and not all that 'beady' (certainly compared to the standing gull).

I'm quite happy to leave a question mark hanging over it as well (or be corrected where the above is wrong).
 
Thanks, Alex. Your comments are much appreciated.

There is something 'different' about this individual, though hard to say precisely what. I thought about barabensis (without really knowing what that meant), but seemed to recall that that form should have worn apical spots by March. Would that not be a problem for this individual?

Also, I found a second individual (same day) with a rectangular-ending tongue, a type that I used to think had a very good chance of being barabensis on account of all the black in the bill. However, after finding so many adult taimyrensis with black bill markings, I quite gave up looking for this form. At that time, though, I had no idea about the underside of P10. Is a rectangular-ending tongue a strong feature of barabensis?

Attached: 2 x Indivdual #77; 1 x taimyrensis with rectangular-ending P10.


Unfortunately not, a rectangular ending tongue is not a strong feature of barabensis. tongue shape and lenght are extremely variable. But question is: is a very long and rectangular ending p10 tongue a strong feature AGAINST a taimyrensis, based on your experience?
 
Unfortunately not, a rectangular ending tongue is not a strong feature of barabensis. tongue shape and lenght are extremely variable. But question is: is a very long and rectangular ending p10 tongue a strong feature AGAINST a taimyrensis, based on your experience?

It would count against taimyrensis, I suppose, but only if in a list of other things that counted against taimyrensis! I haven't paid too much attention to this feature before this year, but there are at least two other taimyrensis with rectangular-ending tongues now in this thread alone.

'Unfortunately not' would seem to be the best answer here too, then! What an absolute headache these East Asian gulls are!
 
Here are a few birds from March 2016 which may be of use or may only serve to confuse matters further!

First, an oiled (but straightforward) vegae, with heavy head streaking and very pink legs. The P10 tongue is long on this bird, and what limited black there is in the outer primaries is distributed mostly along the leading edge.

In the second photo it is stood with a bird I consider to be 'birulai' (though don't really know what this means). The 'birulai' seems to share the same head shape, dark-looking eye, and dull bill of the vegae, but is subtly longer-legged and shorter-winged. From below, the P10 tongue is shorter and slightly wavy-edged, with a further grey 'nick' between where the tongue ends and the white mirror. Something similar is going on in the bird in #80, and I think its head shape (especially the swollen 'snout') is quite similar.

In the last photo, the 'birulai' (whatever that means) is stood with a mongolicus to the left and a taimyrensis to the right. Note how much longer the wings of the taimyrensis look.
 

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The same mongolicus (from March 2016) is interesting in that it show signs of having completed its moult much earlier than the other birds present (worn apical spots from P6 inwards on the folded wing, and worn inner primaries on the spread wing). I would hope to see something like this on a barabensis.

Despite the similar wing pattern (and yellow-toned legs) of this bird, though, I don't think the bird in #77 can be mongolicus (even though it has beady eye better for that form than for taimyrensis). Another feature arguing against mongolicus would seem to be the orbital ring; bright orange-red in mongolicus, more vinous in #77.

In the last photo the bird is with a taimyrensis. The primaries of the taimyrensis are much newer, hence have big unabraded apical spots.
 

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Is birulai a Yellow-legged vega gull?

Hi Alex,

I've read conflicting descriptions of what birulai is supposed to look like (hence the confusion), but have it fixed in mind (rightly or wrongly) that it is a Vega Gull with yellow legs, so yes. That impression comes mostly from an old Birds Korea article (link below, Fig 8), but the birds I am choosing to call birulai could be any one of: actual birulai; hybrid birulai x taimyrensis; or misidentified pale-end taimyrensis. They certainly aren't typical taimyrensis, as can be seen from the direct comparison between birds above (and also the bird in #31).

http://www.birdskorea.org/Birds/Identification/ID_Notes/BK-ID-Herring-Gull-Page1.shtml
 
Appalling light conditions today, and limited time, so one site only and disappointing photos. A small taimyrensis was potentially the most interesting bird present (furthest right in the first photo). This had small apical spots (as if worn), bright bare parts, black on the upper mandible, and a square-ended (but very short) tongue on P10. I'd like this to be barabensis, but I think shape and structure looks all taimyrensis.
 

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With many mongolicus already having gone north, the assemblage here is predictable and repetitive. However, it's not without interest. Attached are four first-winter taimyrensis taken today, showing the astonishing range in appearance that is possible in spring (from practically juvenile to first-summer).
 

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A second-winter taimyrensis (which may have been around for a while) was also around today. Many of the adult taimyrensis that remain are quite strange, being much paler-mantled than the typical 'Heuglin's'-type.
 

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The odder individual with worn apical spots was also present. Interesting how much red there is on the upper mandible of this bird, and I'll have to take a look back at other photos of taimyrensis to see if it is unusual in this regard. A single mongolicus was also present, which too had worn apical spots (so moulted earlier).
 

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What looked like the 'not sure' in #77 also turned up. The orange tones to the legs of this bird are extreme even for taimyrensis.
 

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And finally an unusual and smallish gull that has been around for some time. The very pale saddle, dull bill, and pinkish legs suggest vegae, but there's too much black in the wingtip for that. The underside of P10 and the single small mirror look better for taimyrensis (albeit an extreme 'pale-end' individual).
 

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Close to the end with these gulls now, I think. Today's birds were predictable, and in worse light than yesterday. All the birds below are taimyrensis, with the first two the same small, pale-backed individual; the third a first-winter which still looks surprisingly dark; the fourth a very aggressive male coming in to land; and the last bird another aggressive male squaring up to the 'unknown' of #80.
 

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