Faint pigmented Kumlien's?

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Kent Olsen
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Faint pigmented Kumlien's?

Post by Kent Olsen » Mon Feb 27, 2012 11:02 am

When I look at the excellent work by Howell & Mactavish (2003) I think one type may be missing if it is a Kumlien’s Gull I have in mind. It is a type where the outer webs of the outer primaries are not obviously dark pigmented and approach the type a (stage 0) or somewhere between the type a (stage 0) and type b-c (stage 1) except for the presence of faint subterminal bands near the tip of at least p8-p9. Sometimes it gives the impression of a faint “string of pearls” due to the pigmentation on inner primary webs reach further towards the tip than what I find typical for glaucoides. One could argue that such a primary pattern would fit in right with the type d-f (stage 2) with respect to the subterminal primary band, whereas the colouring of the outer webs would fit in between type a (stage 0) and type b-c (stage 1).

Do such individuals ever occur in Newfoundland?

We have seen several such individuals in Denmark this winter and we have trouble to decide what to think of them. This is the same Danish individual in all the links

http://gulldk.blogspot.com/2012/02/icel ... cy_18.html
http://4.bp.blogspot.com/-OZ1Bxyfxl88/T ... liens1.jpg
http://1.bp.blogspot.com/-6OrtfB_L_ww/T ... 0/kum1.jpg
http://3.bp.blogspot.com/-ijFlI2D-peI/T ... /kum11.jpg

Any comments are more than welcome...

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marsmuusse
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Re: Faint pigmented Kumlien's?

Post by marsmuusse » Mon Feb 27, 2012 2:20 pm

Hi Kent,
None of the birds you refer to are completely adult plumage individuals. I think this is important to bear in mind, when using the Howell-Mactavish classification. You may know pigmentation is known to decrease with age; nevertheless it may also remain to a certain extent.
So you are perfectly right in asking where to draw a line, IF such birds were adults. In fact, the same 'ghost patterns', including sub-terminal bands in extremely pale grey, are also possible in full adults seen in Iceland, photographed by Hans Larsson. We'll see where they fit in best: glaucoides, kumlieni ort the section unidentified...

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JanJ
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Re: Faint pigmented Kumlien's?

Post by JanJ » Mon Feb 27, 2012 4:08 pm

I think we have to expect further examples of different pattern for kumlieni types, than those shown in the Howell & Mactavish article (not a major surprice I gather ;) ). Just by looking at Silas site (http://birdingfaroes.wordpress.com/auth ... ingfaroes/) with the huge numbers of, both kumlieni & glaucoides that have occured there (and elsewhere) is enough to be somehow cunfused about the various plumages in certain individuals regarding 'both'
More to be said here, and exiting!

JanJ

Kent Olsen
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Re: Faint pigmented Kumlien's?

Post by Kent Olsen » Mon Feb 27, 2012 9:25 pm

Yes, very exciting. It would be interesting to hear whether the pattern I describe occurs in Newfoundland or if it is only seen on this side of the Atlantic, incl. Iceland.

Is the later the case it may indicate that the influx this winter may have originated from an area which involves a high degree of backcrossing or introgression of kumlieni into glaucoides... depending on what you think of Kumlien’s Gull, hybrid swarm, subspecies of glaucoides og a true species ;-)

It is a good point about only using the classification system on adults. However, I chose the Danish individual as to illustrate what kind of patter I was thinking of. It is also visible in this photo: http://birdingfaroes.files.wordpress.co ... dv-a56.jpg. However, not necessarily, as the outer primary webs are somewhat obscured and it is hard to tell whether they are darker pigmented than in glaucoides

adriaens
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Re: Faint pigmented Kumlien's?

Post by adriaens » Tue Feb 28, 2012 9:50 am

Speculation about "a high degree of introgression of kumlieni into glaucoides" comes up now and then on internet forums.
However, it always makes me wonder. How exactly would this happen? The breeding ranges of these two taxa are separated by a wide sea, the Davis Strait.

Kent Olsen
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Re: Faint pigmented Kumlien's?

Post by Kent Olsen » Tue Feb 28, 2012 12:46 pm

Peter, you have a point. However, according to my knowledge few Kumlien´s does occur within glaucoides colonies in Greenland. Not that many, but e.g. David Boertmann has a photo of a par in Ilulissat: http://www.netfugl.dk/pictures.php?id=s ... e_id=10132 and Lars Witting mentions that they have found a couple of mixed breeding pairs around Nuuk.

But, this is not what I find interesting. I am more interested in what people think of the pattern pattern I mentioned. Are they seen in Newfoundland Kumlien’s Gulls?

adriaens
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Re: Faint pigmented Kumlien's?

Post by adriaens » Tue Feb 28, 2012 4:57 pm

Interesting. I was aware of two breeding records from Greenland, and of Lars Witting's report, but not of this photograph by Boertmann.
However, none of these (few) records actually seems to refer to mixed breeding of kumlieni x glaucoides?

Newfoundland gets some very pale-winged adult birds every winter, e.g. http://www.aerc.eu/KumliensGull/Adult/Pale/index.htm.
I cannot say that I have seen one with the exact same pattern as the Danish bird, but that is something that Bruce Mactavish or Dave Brown can be of much more help with than me.

lou bertalan
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Re: Faint pigmented Kumlien's?

Post by lou bertalan » Fri Mar 02, 2012 7:34 am

adriaens wrote:Interesting. I was aware of two breeding records from Greenland, and of Lars Witting's report, but not of this photograph by Boertmann.
However, none of these (few) records actually seems to refer to mixed breeding of kumlieni x glaucoides?

Newfoundland gets some very pale-winged adult birds every winter, e.g. http://www.aerc.eu/KumliensGull/Adult/Pale/index.htm.
I cannot say that I have seen one with the exact same pattern as the Danish bird, but that is something that Bruce Mactavish or Dave Brown can be of much more help with than me.
hi peter,

don't know if you can read german. this is what detlef gruber recently wrote on club300.de - there's of course no mentioned interbreeding but he links some more examples of presumed kumlieni from western greenland and supposes that adult "iceland" gulls on greenland have a certain variation, maybe because of intergration with kumlieni. and: somewhere i had found a map of an island (near baffinland?) where adjacent colonies of both taxons had been mapped. can't find the source right now.
detlef:


"Polarmöwen – weitere Aspekte zum Einflug 2012 & Studium

Moin

In den letzten Wochen konnten die Beobachter in Norddeutschland die eindrucksvolle Variabilität von Eis- & Polarmöwen studieren. Viele Beobachter konnten nun für sich die Erfahrung sammeln, dass die verschiedenen Individuen dieser Arten nicht immer „gleich“ aussehen. Das führte auch dazu, in den etwas dunkleren Individuen der Polarmöwe die Form „kumlieni“ zu sehen, was möglicherweise auch zutreffend ist.

Ich möchte hier noch einige Aspekte aus der Brutheimat dieser Vögel liefern, in der Hoffnung, dass das komplexe Thema hier auch in der Komplexität besser verstanden wird.

So z. Bsp. die Frage, wie sehen denn die in Grönland zur Brutzeit anwesenden ADULTEN Großmöwen der Art „Polarmöwe“ aus?
Hier anbei einige Links die zeigen, wie variabel diese Möwen dort tatsächlich aussehen. Ganz offensichtlich findet eine Vermischung in Grönland statt. Somit sind auch in Deutschland alle „fließenden Übergangsformen“ zu erwarten, bzw. „kumlieni“ besser als eine Farbmorphe mit Flügelabzeichen, die aber aus exakt der gleichen Brutpopulation stammen kann wie Möwen ohne solche Abzeichen.
Übertragen auf unsere Heringsmöwen „Dutch Intergrades“ wären es dann „Greenland Intergrades“. Wer von uns unterscheidet die Heringsmöwen „graellsii“ von „intermedius“ wenn wir diese in Brutkolonien an der Nordseeküste beobachten?
Warum ist es dann sinnvoll hier „kumlieni“ von „glaucoides“ zu unterscheiden???
Oder ein anderes Beispiel wäre an der US Westküste die Übergangs- Mischformen zwischen der West- zur Beringmöwe.

Ritenbenk, Ilulissat Kommune, Grønland 10. juli 2006 (Westküste Grönland, also "gegenüber" von Baffin Island / Kanada)
http://www.netfugl.dk/pictures.php?id=s ... e_id=12922

Qamavik nord for Ilulissat/Jakobshavn, Grønland 4. juli 2005 (dito Westküste)
http://www.netfugl.dk/pictures.php?id=s ... e_id=10132

Nuuk, Grønland 7. februar 2005 (dito Westküste)
http://www.netfugl.dk/pictures.php?id=s ... re_id=5383

Nuuk, Grønland 1. maj 2004
http://www.netfugl.dk/pictures.php?id=s ... re_id=2660

Zu der Frage, wie dunkel können Kumlienmöwen in K1/K2 erscheinen, siehe folgendes Beispiel:

St. Johns, Newfoundland, Canada 18. december 2001
http://www.netfugl.dk/pictures.php?id=s ... ure_id=347
Bruce Mactavish’s comment to the photo:
I enclose a photo of a dark end 1st winter Kumlien's Gull from St. Johns, Newfoundland taken December 18, 2001. The scapulars, like the Thayer's, are still all juvenile and are fuller and darker than most Kumlien's, but are not solid dark brown with pale fringes like the Thayer's. The folded primaries are a little darker than the upper parts but the upper parts are relatively pale compared to the Thayer's. The body and hind neck is a paler brown wash, and it is whiter around the head. The bill on this bird is starting to get pale at the base, however, many Kumlien's have all black bills in December.

Lesenswert auch die Zusammenfassung aus folgender Publikation:

Hybridization and changes in the distribution of Iceland gulls (Larus glaucoides/kumlieni/thayeri
D. N. Weir1, A. C. Kitchener1,2, R. Y. McGowan1
Journal of Zoology Volume 252, Issue 4, pages 517–530, December 2000

Three Iceland gull taxa were defined mainly from adult wingtip melanism. Up until about 1860, nominate glaucoides (no melanism) was known to breed from Greenland to western High Arctic Canada, but by about 1900 it was essentially confined to Greenland. Until 1860, thayeri (most melanism) was known only from western High Arctic Canada, but from 1900 to 1980 it was found throughout High Arctic Canada and in a small part of north-west Greenland. At high latitudes in Canada it replaced glaucoides, with which it was formerly sympatric in the west and probably interbred. The first known kumlieni (intermediate, variable melanism) were from west Greenland in the 1840s, and by 1900 the western and northern limits of most of its breeding range in the eastern Canadian Low/High Arctic were known. The range of kumlieni lies between those of thayeri and glaucoides and overlaps both; kumlieni bred in Greenland by 1964.

It freely interbreeds with thayeri and probably with glaucoides.

Winter ranges of glaucoides and thayeri have changed little since they were first determined for glaucoides by 1860 and for thayeri by the 1920s. However, winter adult kumlieni was unknown from Greenland to the British Isles until 1900; there were a few records prior to 1915 and progressively more after 1950.

The study adds to the evidence that kumlieni represents introgressive hybridization by western thayeri into eastern glaucoides.

Wer kann mir bitte diese Arbeit als PDF Datei zur Verfügung stellen?

Gruß
DG
"

cheers

lou

Silas
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Re: Faint pigmented Kumlien's?

Post by Silas » Mon Mar 05, 2012 12:37 pm

Hi!

The total number of Iceland Gull-types on the Faroes during january and february exceeds 4000 birds including hundreds and hundreds of Kumlien's Gulls. When talking about the primary pattern it is important to be sure that we're dealing with adult birds - this excludes weird/abberant patterns formed by retained moult/letf-over pigmentation etc.

I've made a collection of pics showing different primary patterns that I've seen on adult birds the last two months: http://birdingfaroes.wordpress.com/2012 ... y-pattern/

Best regards,

Silas

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