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Old Tuesday 14th March 2017, 16:42   #101
balex78
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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.
But what else it could be? Taimyrensis seems like the most valid option
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Old Tuesday 14th March 2017, 16:47   #102
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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.
the adult one facing right...what about mongolicus?
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Old Wednesday 15th March 2017, 14:57   #103
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But what else it could be? Taimyrensis seems like the most valid option
That certainly makes the most sense, even though it doesn't really resemble one when stood.
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Old Wednesday 15th March 2017, 15:14   #104
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the adult one facing right...what about mongolicus?
I still think this is better for some kind of vegae for reasons given in #87. Retarded mongolicus is an option, but it is very retarded (mongolicus have finished moulting primaries by December here) and has less black in the wingtip than usual for mongolicus.
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Old Friday 17th March 2017, 13:12   #105
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Struggling to find many gulls now. Just four taimyrensis today, of which two would be photographed.
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Old Saturday 18th March 2017, 13:20   #106
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As all the southerly-distributed taxa (i.e. mongolicus) have already gone north, only more northerly-distributed ones (i.e. taimyrensis) remain. I'm starting to get bored myself now with the limited diversity on offer, and it may be about time to get stuck into some passerines.
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Old Monday 20th March 2017, 12:38   #107
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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.
Looks like intermediate between mogolicus and taimyrensis. Pretty long and oval ending tongue on the underside of p10 (more mongolicus like) Can the two hybridize?
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Old Monday 20th March 2017, 12:45   #108
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Struggling to find many gulls now. Just four taimyrensis today, of which two would be photographed.
The thing that worries me the most is that long tongue on p10, reaching half the lenght of the feather. Is that a variation of taymirensis? The rest fits a taimyrensis well!
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Old Monday 20th March 2017, 15:24   #109
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Looks like intermediate between mogolicus and taimyrensis. Pretty long and oval ending tongue on the underside of p10 (more mongolicus like) Can the two hybridize?
They are separated by quite some distance, so it seems unlikely. The P10 tongue is variable in the other taxa in the assemblage here, so I don't see why it shouldn't also be in taimyrensis (as it is anyway a 'hybrid swarm', we might expect it to be moreso).
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Old Monday 20th March 2017, 15:30   #110
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The thing that worries me the most is that long tongue on p10, reaching half the lenght of the feather. Is that a variation of taymirensis? The rest fits a taimyrensis well!
I think that the darker birds with shortish diagonal tongues may represent 'heuglini-end' birds. Assuming a cline into vegae, pretty much anything should then be possible on the underside of P10 (as it seems to be on vegae: http://www.surfbirds.com/ID%20Articles/JapanGulls/).
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Old Monday 20th March 2017, 16:13   #111
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So, both heuglini and taimyrensis are present there?
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Old Monday 20th March 2017, 17:21   #112
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So, both heuglini and taimyrensis are present there?
Hi Alex,

Now you've now got me very confused!

The term 'taimyrensis' does not appear on either IOC or Clements Checklists, so presumably neither consider it a valid taxon. I assume the term to relate to a stable hybrid swarm between heuglini in the west and vegae in the east, and that its former lumping with heuglini followed from it having more in common in terms of morphology with that taxon than with vegae (including the short diagonal tongue on P10 I have been seeing a lot of). In short, I assumed that taimyrensis might be variable in appearance, but that most should strongly resemble heuglini (hence 'heuglini-end', meaning 'heuglini-like, and inferring some heuglini 'influence').

I may well have all this wrong; my understanding of the biology of these things is rudimentary at best! Should taimyrensis be more 'fixed' in terms of its appearance and differ markedly from heuglini? If so, I have no idea in what way these two 'forms' actually differ. And if it does differ in a consistent way, why is taimyrensis no longer considered a 'good' form? Is it just a now obsolete synonym for heuglini? (In which case, yes, heuglini would be present here.)

Last edited by SteveMM : Tuesday 21st March 2017 at 04:02. Reason: Lack of clarity (which unfortunately persists)
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Old Wednesday 22nd March 2017, 06:07   #113
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Hi Alex,

Now you've now got me very confused!

The term 'taimyrensis' does not appear on either IOC or Clements Checklists, so presumably neither consider it a valid taxon. I assume the term to relate to a stable hybrid swarm between heuglini in the west and vegae in the east, and that its former lumping with heuglini followed from it having more in common in terms of morphology with that taxon than with vegae (including the short diagonal tongue on P10 I have been seeing a lot of). In short, I assumed that taimyrensis might be variable in appearance, but that most should strongly resemble heuglini (hence 'heuglini-end', meaning 'heuglini-like, and inferring some heuglini 'influence').

I may well have all this wrong; my understanding of the biology of these things is rudimentary at best! Should taimyrensis be more 'fixed' in terms of its appearance and differ markedly from heuglini? If so, I have no idea in what way these two 'forms' actually differ. And if it does differ in a consistent way, why is taimyrensis no longer considered a 'good' form? Is it just a now obsolete synonym for heuglini? (In which case, yes, heuglini would be present here.)

Let me try and clarify the utter gibberish of my last post:

IMO (i) heuglini does not occur here, taimyrensis does; (ii) a typical taimyrensis bears a strong resemblance to a typical heuglini; (iii) with no real field experience of heuglini, I would personally be unable to pick one out from a taimyrensis in the field (especially in a vagrant context), and (ii) may be incorrect.

This leaves me with questions:

If taimyrensis is readily separable from other taxa in the region in first-winter plumage (by dark hand, dark greater coverts etc (see all the posts above)); has a different moult strategy to other taxa in the region (rapid acquisition of first-summer plumage (with 'adult-like' feathers)); is generally readily separable from other taxa in the region in adult plumage (darker upperparts, deep yellow-amber legs); has a different moult strategy to other taxa in the region as an adult (late primary moult), then why isn't it either (i) included within heuglini, either as a synonym for it or as a race (as the above are all shared by heuglini (right?)), or (ii) a good species in its own right (as is suggested by the use of L. taimyrensis in this paper: http://gull-research.org/papers/gull...11_pag9_21.pdf)?

Looking at gulls on their wintering grounds only precludes me from answering either of the questions above. As I can readily pick out typical or 'Gestalt' individuals in the field, though, the 'hybrid swarm' explanation doesn't feel very satisfactory (given the amount of individual variation that is present in other big gull taxa anyway). Also, I can't tick it!

Hope that goes some way to clearing up the wine-infused drivel of #112. It is strange how I'd managed to stay completely off the sauce until I started looking at these things!

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Old Wednesday 22nd March 2017, 14:57   #114
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As my sandbar is invariably clogged up with fishermen these days, I'm going to have to dig into photos from previous years to keep this thread 'alive' in any way. Attached are a couple of vegae from late Feb 2016.

The first-winter shows contrasting pale greater coverts, a decidedly inconspicuous 'window' in its 'hand' (like taimyrensis), but no sign of feather replacement in its mantle or lesser coverts (unlike taimyrensis). With such a dark body and tail, I initially thought I might have an American Herring Gull in this individual, but the pale greater coverts effectively rule that out.

The adult shows head markings too extreme for taimyrensis, and the pale mantle and pink legs also rule that 'form' (whatever the **** it is) out. I have over time come to associate dark eyes with vegae, though this association might not be valid.
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Old Wednesday 22nd March 2017, 15:35   #115
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And another first-winter vegae I dug out, this time from March 2016. Amazing how crisp and fresh it looks compared to other gulls at this time of year, and with no feather replacement above.

And my first ever tropical Glaucous Gull on the same day last year. As there's no real ID issue with this one, it's not a heavily cropped shot. And of course you would always want to keep that tern in the frame anyway!
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Old Thursday 23rd March 2017, 19:10   #116
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As my sandbar is invariably clogged up with fishermen these days, I'm going to have to dig into photos from previous years to keep this thread 'alive' in any way. Attached are a couple of vegae from late Feb 2016.

The first-winter shows contrasting pale greater coverts, a decidedly inconspicuous 'window' in its 'hand' (like taimyrensis), but no sign of feather replacement in its mantle or lesser coverts (unlike taimyrensis). With such a dark body and tail, I initially thought I might have an American Herring Gull in this individual, but the pale greater coverts effectively rule that out.

The adult shows head markings too extreme for taimyrensis, and the pale mantle and pink legs also rule that 'form' (whatever the **** it is) out. I have over time come to associate dark eyes with vegae, though this association might not be valid.
scaps and mantle seem to be replaced with 2nd gen feathers here
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Old Thursday 23rd March 2017, 19:15   #117
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Taimyrensis is slightly different from nominate heuglini. Taimyr often has a slimmer and thinner bill , a smaller ans more rounded head and slightly paler upperparts. Its structure is less bulkier than heuglini's
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Old Friday 24th March 2017, 00:08   #118
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scaps and mantle seem to be replaced with 2nd gen feathers here
Thanks, Alex. The post should read active feather replacement (meant to contrast with the appearance of taimyrensis which now has 'adult-type' mantle and coverts mixed in with retained juvenile ones).

Last edited by SteveMM : Friday 24th March 2017 at 00:15.
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Old Friday 24th March 2017, 00:12   #119
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Taimyrensis is slightly different from nominate heuglini. Taimyr often has a slimmer and thinner bill , a smaller ans more rounded head and slightly paler upperparts. Its structure is less bulkier than heuglini's
Granted, but all these terms are so relative and of little practical use to apply to a set of birds which exhibit so much variation in the first place!

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Old Friday 24th March 2017, 16:02   #120
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Thanks, Alex. The post should read active feather replacement (meant to contrast with the appearance of taimyrensis which now has 'adult-type' mantle and coverts mixed in with retained juvenile ones).
You are correct. The taimyrensis ones I think are 2nd gen scapulars which are adult like in pattern, but I don't think a first winter bird can show adult scapulars..

Any other pics you can post, Steve? from previous years thy're ok as well :-)
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Old Sunday 26th March 2017, 15:13   #121
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You are correct. The taimyrensis ones I think are 2nd gen scapulars which are adult like in pattern, but I don't think a first winter bird can show adult scapulars..

Any other pics you can post, Steve? from previous years thy're ok as well :-)
A few pics from today in grim overcast conditions. First, the much sought-after oddball from #52 (thayeri-like wingtip), which finally put in a second brief appearance in my small harbour.

This (unfortunately) is not a Thayer's Gull judging by the very heavy bill, and there is far too much black in p9. Exactly what it is, though, I really don't know!
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Old Sunday 26th March 2017, 15:14   #122
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Of course, taimyrensis gulls.
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Old Sunday 26th March 2017, 15:19   #123
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And the Glaucous Gull still hanging around. Quite a small individual.
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Old Yesterday, 07:22   #124
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A few pics from today in grim overcast conditions. First, the much sought-after oddball from #52 (thayeri-like wingtip), which finally put in a second brief appearance in my small harbour.

This (unfortunately) is not a Thayer's Gull judging by the very heavy bill, and there is far too much black in p9. Exactly what it is, though, I really don't know!

Have you thought about a Vega?
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Old Yesterday, 10:01   #125
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Have you thought about a Vega?
Yes. I dismissed Vega at first as the bird looked quite a bit smaller than taimyrensis and not much like a 'typical' Vega elsewhere (bright bill, white head). However, vegae is in truth the only possible option.

I also suspect that it is a 'pure' individual rather than a hybrid of any kind, and that the variation in wingtip pattern in vegae must then be wider than generally described (on the evidence of two birds now this winter, it can resemble e.g. argentatus).

I'm still happy and relieved that this bird turned up again; I was slowly talking myself into ticking it as Thayer's!
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