Thayer's Gull?

[Bobolink44]

Anyone like to comment on the recent gull photos on UK Stop Press (http://www.surfbirds.com/cgi-bin/gallery/display.cgi?gallery=gallery9). Good ones of the relocated Dix pit bird in Derbys by Pete Wragg which seems to be best left unidentified. But what about the flying bird at Staveley by Steven Botham - aren't the primaries too pale for Thayer's?

:lovegulls:

[Vermfly]

If we saw either of those birds here in California it would be pretty close to a slamdunk for Thayer's I think. The first bird has the typical small bill, dark eyes, darker wing tips but light underneath. The flying bird pictured looks good as well. From underneath the primaries would look very pale.

[andy22]

Anyone like to comment on the recent gull photos on UK Stop Press (http://www.surfbirds.com/cgi-bin/gallery/display.cgi?gallery=gallery9). Good ones of the relocated Dix pit bird in Derbys by Pete Wragg which seems to be best left unidentified.

:lovegulls:

I was wondering, i went up and saw the dix pit bird and i dont understand why people have left it unidentified? Was it a hybrid or a pure gull?

cheers andy

[Sean Cole]

Both sets of photos show the same bird, which is as stated the bird which was at Dix Pit.

The upper primaries show the venetian blind effect, the undersides of the primaries, as the photo's show, are very pale.

The bird is the size of a Herring gull. It seems to have an Iceland gull-like head, which seems too small for the body.

An odd looking creature. Thinking seems to be that it is a hybrid - maybe HerringxIceland?

Regards

Sean

[garry1366]

Both sets of photos show the same bird, which is as stated the bird which was at Dix Pit.

The upper primaries show the venetian blind effect, the undersides of the primaries, as the photo's show, are very pale.

The bird is the size of a Herring gull. It seems to have an Iceland gull-like head, which seems too small for the body.

An odd looking creature. Thinking seems to be that it is a hybrid - maybe HerringxIceland?

Regards

Sean

Hi Sean,
I'm not sure who is saying that this has Herring in it, I've certainly not heard anyone suggest this?

I think most people are assuming it's either a Kumlien's from the extreme Thayer's end of the range or a pale Thayer's.

Garry

[AndyB]

I'd agree with Vermfly. I feel very lazy reading the discussion this bird has generated elsewhere. I'm not looking at these gulls closely enough.

Trying to record a Kumlien's on the west coast is a very hard task indeed (even a good looking bird such as this one (http://www.charliesbirdblog.com/~charlie/kumleinsSFO06mar05/kumleinsSFO06mar05.html)). So in California, I would have noted the UK bird as a Thayer's. The hybrids are prevalent and lots of Glaucous-winged hybrids around here but nothing about the UK bird that looks like a Glaucous-winged hybrid - structurally these hybrids can be separated from Thayer's.

Obviously, any out of range bird needs to be scrutinized so on the UK bird, paler tertials, barred scapulars, lack of tail band are not classic but so is this bird from California (http://www.pbase.com/jpkln/image/33948452) or this one showing milky tertials (http://www.pbase.com/jpkln/image/56742827). Southern CA birds also get a little sun-bleached and the unwary have to be alert to these birds (http://www.pbase.com/jpkln/image/92389255).

Presumably, Kumlien's integrades occur on the west coast and we're passing them off as pure Thayer's?

By the way, if you haven't seen it, Jeff Poklen has a great page of Thayer's (http://www.pbase.com/jpkln/thayers) and Kumlien's (http://www.pbase.com/jpkln/kumliens_1)

Photos of the UK bird are below:

Thayer's type Gull, Oxon, Dix pit Jan 08 © Ian Lewington
http://www.surfbirds.com/media/gallery_photos/20080113022044.jpg
http://www.surfbirds.com/media/gallery_photos/20080113021734.jpg
http://www.surfbirds.com/media/gallery_photos/20080105043758.jpg

Kumlien's Gull, Oxon, Dix Pit 7th December 2007 © Nic Hallam
http://www.surfbirds.com/media/gallery_photos/20071207105329.jpg

Kumlien's/Thayer's type Gull, Oxon, Dix Pit 5th December © Nic Hallam
http://www.surfbirds.com/media/gallery_photos/20071206003223.jpg

Thayer's type Gull, Derbys, Poolsbrook 17th Feb 08 © Pete Wragg
http://www.surfbirds.com/media/gallery_photos/20080217121543.jpg
http://www.surfbirds.com/media/gallery_photos/20080217121400.jpg
http://www.surfbirds.com/media/gallery_photos/20080217121239.jpg

[Sean Cole]

Hi Sean,
I'm not sure who is saying that this has Herring in it, I've certainly not heard anyone suggest this?

I think most people are assuming it's either a Kumlien's from the extreme Thayer's end of the range or a pale Thayer's.

Garry

Certainly one conversation I've had with someone I respect highly as a gull expert has suggested the hybrid possibility, and alluded to the conclusion that the bird was potentially indeterminable. There is a school of thought that says some of the American photos of Non-classic gulls that resemble extralimital problem birds aren't actually pure birds either!!

My question is, can Thayer's or Iceland/Kumlien's be the same size as Herring gull? This bird is exactly the same size.

Please bear in mind that gulls are a major turn-off for me, and my knowledge on i.d. of these variants is probably a bit out of date. I also have not referred to any literature (as you can probably tell).

For me, I'd like it to be a Thayer's, but I think given the amount of time it has been present, along with the quality of the views and photographs available, I would have expected it to have been nailed by now by those who do know what they are talking about.

Andy - your links do not work for me unfortunately.

Sean

[garry1366]

Certainly one conversation I've had with someone I respect highly as a gull expert has suggested the hybrid possibility, and alluded to the conclusion that the bird was potentially indeterminable. There is a school of thought that says some of the American photos of Non-classic gulls that resemble extralimital problem birds aren't actually pure birds either!!

My question is, can Thayer's or Iceland/Kumlien's be the same size as Herring gull? This bird is exactly the same size.

Please bear in mind that gulls are a major turn-off for me, and my knowledge on i.d. of these variants is probably a bit out of date. I also have not referred to any literature (as you can probably tell).

For me, I'd like it to be a Thayer's, but I think given the amount of time it has been present, along with the quality of the views and photographs available, I would have expected it to have been nailed by now by those who do know what they are talking about.

Andy - your links do not work for me unfortunately.

Sean

Hi Sean,

I thought the bird was clearly smaller than HG, have you seen it in the flesh or just pics?

The previous day I saw an Iceland at Moore tip in Chesire that was massive easily as big as HG and almost Glauc like in proportions. So the answer is yes they can be the same size as HG.

I think the fact that Martin Garner is in the Thayer's camp must sway the previous argument slightly?

G

[JanJ]

Just thinking of how difficult thayeri - thayeri/kumlieni - kumlieni/glaucoides (or anyway you like it), stil are to identify - of course especially out of range birds. We know how they look but not what to call them, but much to say about them. Take a look at Dick Newell,s suggestion on ID-FRONTIERS:

http://www.virtualbirder.com/bmail/idfrontiers/latest.html

and note that what he say´s (no offence Dick) about the Derbyshire gull would be considered as mere variation in any other LWHG. Of course there´s need for extra caution in these species/ssp pair, but the Derbyshire bird looks like a thayeri to me, at least my idea of it, as I have learned they should/can look like give and take for variation. A quick look at Jeff Poklens thayeri and kumlieni and birds seen in the US, as also noted by Andy here, gives you the idea of variability, and there are some of them that would not be accepted over here.

http://www.simplybirdsandmoths.co.uk/page441.html

What do you all say about this one then:

http://www.pbase.com/image/89740711

From Florida:

http://www.pbase.com/chnuts/kumliens_thayers_gulls

http://www.pbase.com/ternvomitthief/thayers_gull_tutorial

Regarding size, thayeri is smaller than Herring, but according to measurements, overall size, there´s overlap, and remember that females are smaller than males!

JanJ

[Bonsaibirder]

What do you all say about this one then:
http://www.pbase.com/image/89740711
From Florida:
http://www.pbase.com/chnuts/kumliens_thayers_gulls
http://www.pbase.com/ternvomitthief/thayers_gull_tutorial
JanJ

Hi JanJ, and all

These are interesting pictures but it appears to me that we are beginning to discuss a non-typical (whatever that means!) Thayer's-type gull by comparing it to pictures of non-typical Thayer's-like gulls. It worries me that any one of these gulls could have been mis-identified - or am I being paranoid?

The first florida link seems to show a bird with a similar large-bodied, small-headed appearance to the Dix Pit bird - but what does that mean?

Just to be clear - I have very little experrience with Thayer's Gull and I haven't seen the bird in question - I am just questioning the approach.

Fascinating stuff, whatever.

[JanJ]

Hi Steve.

Not wanting to confuse the matter - simply a thought and note of, perhaps putting to much reliability into scapular, greater coverts and tertial pattern, not that I´m saying it is of no importance, but maybe taking it to it´s extreme, which we tend not to do in other LWHG taxa, but refer to it as variability and wear and rely on other features like bill size/shape jizz and of course the overall picture - all characters put together. In thayeri, kumlieni this seems so much more difficult, partly because of variability and wear, partly due to lack of knowledge it seems. Anyway my ingoing here on this matter is not criticizing anyone or trying to make thayeri identification a simple thing (!), mearly some thoughts on the subject and Dick,s note - especially the scapular pattern - which seems to be worn juvenile feathers along with a few moulted ones (restricted in thayeri)

Compare with the recent Islandic bird:

http://myndir.fuglar.is/picture.view.php?picture_id=1774

Does the linked Florida gull strike all as a thayeri?

JanJ

[AndyB]

What do you all say about this one then:
http://www.pbase.com/image/89740711

This looks very Glaucous-winged to me. Bill color not right but structurally looks more like Glaucous-winged than a Thayer's.

Florida bird again shows some anomalous features for classic Thayer's but if I saw it on a California beach I wouldn't try to claim it as Kumlien's or worry that it was a hybrid. Would probably note it as a Thayer's. But I could be lazy and might be mis-IDing Thayer's and hybrids left and right.

I've been inspired to get out this weekend and study some gulls. Photos to follow.

[Bonsaibirder]

Hi JanJ,

I hope my post didn't come over as a criticism aimed specifically at you - I have learned much from many of your posts on BF and here.

Hi Steve.

Not wanting to confuse the matter...

<snip>

... Does the linked Florida gull strike all as a thayeri?

JanJ

[Sean Cole]

Well, the debate goes on, and I am finding this more and more fascinating as we go along.

To take some of the points made and add some comments:

Firstly, Tony Davison's article (linked by JanJ) I feel is a very accurate summary of both the bird and the situation. He confrims what I have said previously, in that the bird is equal in size to all the Herring gulls it was stood next to. Garry - I saw this bird in the flesh on Sunday at Poolsbrook.

I'll once again re-iterate that I know little about this group when it comes to identification, and my opinions are based more on overall featrues and appearance rather than feather-by-feather detail. On taking this approach I see a mis-proportioned bird which has a jizz unlike any Herring or Iceland I have seen. The small head plonked onto a large gull-type body, and the short but thick bill, seem to smack of a hybrid to me.

As has been stated here by myself and others, we are comparing this bird with photos of other intermediate birds that may have been misidentified in the first place. The bird in the link http://www.pbase.com/image/89740711 , commented upon by Andy, looks similar in shape to the Derbyshire bird and doesn't look like a pure bird either.

Photos of all Kumlien's and Thayer's I've seen (classic ones) show a shape like an Iceland gull and plumage similar to Herring gull, but with the "cutesie" Iceland like expression. This bird looks like some kind of anomaly.

Do we always need the tertial pattern to name a bird correctly?

Before I sign off on the subject (as I've clearly nothing really useful or founded to add to the identification) may I say that I of course will bow down to people with more knowledge and experience than me, as I am not experienced enough in this group to have a valid opinion. But can those people offer objective and demonstrable reasoning for their decisions?

I think I must see that Birding World article....

Ciao

Sean

[JanJ]

Bleached Glaucous-winged, structurally with all (?) white (not just white p-tips) wing tip was also my impression. Looks like a 1st winter (first cycle) - some retained outer medians and lesser coverts. All white wing tip and pale based bill might suggest Glaucous, or some other species involvment but I can´t exclude either, since some bleached 1s cycle Glaucous-winged apparently can show all/near all white wing tip (33.15 in Howell & Dunn) and bill size (female) and pattern like the the subject bird.

http://www.pbase.com/jpkln/image/73766156

wing tip:

http://www.pbase.com/jpkln/image/38075450

JanJ

[AndyB]

I hear what you're saying Sean and you have the advantage of having actually seen the bird rather than backseat commenters like me 6000 miles away. However, I wouldn't let this bird http://www.pbase.com/image/89740711 confuse matters - I don't believe it's a Thayer's and may even be a pure Glaucous-winged.

It's also interesting that the UK bird in the first 2 photos by Ian Lewington appears to have a different softer jizz to it than the same bird in the Nic Hallam photo and again goes to show that pictures are not a good substitute for actually seeing the bird.

Thayer's type Gull, Oxon, Dix pit Jan 08 © Ian Lewington
http://www.surfbirds.com/media/gallery_photos/20080113022044.jpg
http://www.surfbirds.com/media/gallery_photos/20080113021734.jpg

Kumlien's/Thayer's type Gull, Oxon, Dix Pit 5th December © Nic Hallam
http://www.surfbirds.com/media/gallery_photos/20071206003223.jpg

[Sean Cole]

Well, I've been reading up on Thayer's and Kumlien's (perhaps I should have done this earlier!) and it might be appropriate to retract and correct some comments made previously, and re-inforce others

1. Size: it would appear there is complete overlap with Herring gull so if this is a large Thayer's then size shouldn't be an issue. However, this only holds true if none of the Herring gulls it accompanied were medium-to-large sized birds!
2. Jizz and shape v's plumage. This is where I was perhaps most overstated;I wouldn't want to detract form tangible features that would confirm an identification. The only jizz feature about the bird (visible in my eyes form the photo's that Andy has linked above) is the strange shape - i.e. the Thayer's-like head plonked onto a body seemingly too large. It doesn't have the homogenous feel of all the photo's of Thayer's I've seen. Plumage-wise, it would appear (and please anyone correct me if I'm wrong) that the tertial pattern would be the most diagnostic feature? If so, surely this bird has the wrong pattern, even though it is late in the winter.

My understanding is that the overlap area (which creates Kumlien's types?)between Thayer's and Iceland is relatively small. How prevalent is mixed breeding in the pair? And if it is so rife as to product vagrants even on the UK, does this not support the lumping of the Icelnad-Kumlien's-Thayer's group anyway? Are we not talking, as mentioned on Birdforum, about what is essentially a hybrid swarm? My understanding also is that the splitting of Thayer's gull into species status was originally based on a flawed paper going back to 1966?

If I am out of date on any of this, I'd welcome updated knowledge.

All the best

Sean

[Alex Lees]

My understanding is that the overlap area (which creates Kumlien's types?)between Thayer's and Iceland is relatively small. How prevalent is mixed breeding in the pair? And if it is so rife as to product vagrants even on the UK, does this not support the lumping of the Icelnad-Kumlien's-Thayer's group anyway? Are we not talking, as mentioned on Birdforum, about what is essentially a hybrid swarm? My understanding also is that the splitting of Thayer's gull into species status was originally based on a flawed paper going back to 1966?

If I am out of date on any of this, I'd welcome updated knowledge.

All the best

Sean

Hi Sean, all

I have attached the Weir et al. (2004) paper which is probably the best reference on the subject....

cheers

Alex

[AndyB]

Thanks Alex. A good read. Went looking for winter gulls yesterday in San Pedro Harbor. Two 1st yr Glaucous-winged Gulls were the highlight but no Thayer's. Will post some video later. May try Doheny for a Thayer's next weekend...

Sean, if the hybrid issue is as severe as papers suggest, then yes you're right, us west coast N. American birders might have to re-appraise whether we can ID a Thayer's from a Kumlien's and the whole group gets lumped. I can't see a tremendous difference between Ian Lewington's photo of the "hybrid" from Oxfordshire here (http://www.surfbirds.com/media/gallery_photos/20080113021734.jpg) and Jeff Poklen's photo of "pure Thayer's" from a Californian beach here (http://www.pbase.com/jpkln/image/72115374/original).

Best, Andy

[Sean Cole]

Hi Andy

Thanks for that photo. It really is a very close match for the UK bird, and although the proportions of our bird still concern me, on plumage alone it would have to be a Thayer's.

I spent a lot of time looking at Jeff Poklen's site and just got more and more confused! I think this is down to the sheer amount of variability within Thayer's.

Given the latter, what are the definitive features used to clinch a definite Thayer's against the various hybrids and Kumlien's? It seems scapular, tail, greater cover and rump pattern aren't consistent, that it is more down to wing pattern and general shape/proportions. Unfortunately this brings me back round to where I started with this species!!!

Sean

[AndyB]

You could be right Sean. We're back where we started. If the article Alex attached is correct, then it's a bit of an impossible situation. However, it would also appear from the range maps that the Kumlien's hybrid situation seems to be closer to the eastern seaboard and less of an issue for west coast birders (where Kumlien's is very rare and hard to prove). However, it's a pain for birders on the eastern seaboard and the Europeans!!

I think we're faced with either accepting that there is some variability among the Thayer's plumages and sites like Jeff Poklen's west coast photos only highlight that (which means the UK bird could fall within the range of a pure Thayer's) or this dramatic sounding "hybrid swarm" is responsible for many un-IDed Kumlien's type hybrids on the west coast too. This only complicates matters when we google Thayer's reference images from west coast N. America and are expecting all photos to show pure Thayer's.