Gull taxonomy (1 Viewer)

One day I will discuss other birds as I really do know about lots of birds but if you haven't guessed by now, gulls are my favorites.

Where does everyone stand as far as which are distinct and which belong lumped with another? I suppose it will depend on which checklist you follow. I sort of combine European and American checklist. Here are my thoughts on the relationships among gulls:

American and European Herring...to me single species. Immature plumages differ but adults in most cases, with the exception of northern European birds would be virtually impossible to tell apart. There are very slight differences in voice quality but this also happens in a number of other species geographically as well. Long call displays are the same.

Thayer's; deffinate a good decision to split it from Herring 25 years ago. Generally I regard it as seperate from Iceland based mainly on the fact that Kumlien's shows characteristics of being a hybrid population. Meaning that it's too variable to be a stable subspecies. You can point to the more consistant differences between graellsii and intermedius or occidentalis/wymani. Kumlien's seems as variable as "Olympic" Gull and "Nelson's" Gull. Don't know anything about their calls as They are normally silent away from the breeding grounds.

Lesser Black-Backed/Baltic Gull: I know that some authority's have split them. I tentatively follow this treatment. The differences bewteen these two seem rather similar to Thayer's and Icaland. Even more interesting is that fuscus rarely interbreeds with graellsii/intermedius Familiar with LBB calls stragely enough but know nothing about Baltic. You can see a video of LBBG calling here. You may need to turn your volume up to here them well.
http://ibc.hbw.com/ibc/phtml/votacio.phtml?idVideo=775&tipus=1

Kelp Gull and Cape Gull: This is a new one to me. Need to find out more.
a group of Kelp Gulls fighting and calling. Notice the head doesn't point as far up as LBBG and the calls are faster, rather resemble California Gulls exactly like the captive birds I've seen:
http://ibc.hbw.com/ibc/phtml/votacio.phtml?idVideo=1477&tipus=1

Yellow-Footed and Western Gulls: Another good splitting decision. Yellow-Footed for starters is a three year gull not a four year gull. Voices are different.

Yellow-Legged/Caspian: Seems like a good move but I am still learning about their biology. Certainly good seperating them from Herring Gulls.

Western and Gluacous Winged: Ok these are the two large gulls I have the most personal experience with. I regard them as seperate. If you were to here them call you would know it's two similar sounding but distinct species. The calls of hybrids are also intermediate.

ok JanJ and all others who know about gulls. What are your opinions?

Let's start with the rather clear ones:
American and European Herring: split. They look alike, but seem not that closely related at all.
Yellow-legged and Caspian: split! Very different birds in every aspect. Atlantic Gull stays with Yellow-legged. Armenian Gull should be apart.
Now it gets worse:
Baltic and Lesser Black-backed: lump. They seem to merge nicely via intermedius.
Heuglin's and Steppe Gull (barabensis) (combined) I'd put apart from the LBBG to be sure...
And now the melting pot: Any gull coming close to the Bering Strait seems to share its DNA with up to four other taxa, even though they look quite different. So Iceland, Glaucous, East Siberian (= Vega + Mongolian), Slaty-backed and Glaucous-winged all deserve to be treated apart I guess.
Funnily, Western Gull is quite distantly related to these!
Most of this based on "The herring gull complex is not a ring species" by Liebers et al.

Question: I thought Baltic gull (Larus fuscus fuscus) was considered rather different from graellsi and intermedius (though not nessecarily a different species) and those last two much closer together genetically? Is that wrong?

And is there interbreeding between fuscus and intermedius?

a good answer to your question, jörn, again is found in liebers/helbig: "phylogeography and colonization of lesser black-backed gull (larus fuscus) as revealed by mtDNA sequences" is a good read! i'm looking for a link. well, just the google-link to the pdf: http://www.google.com/search?source...(larus+fuscus)+as+revealed+by+mtDNA+sequences

hope it works (uaaa is that a long adress...)

in short: there's a clear genetical "step" (of difference) between heuglins gull and baltic but not so much between all the fuscus-taxa. colonization occured from east to west (heuglini-fuscus-graellsii). so graellsii-fuscus-intermedius is definitely one species, heuglini/"taimyrensis" related but not so close (more of a superspecies). as for the strong differences between baltic and western LBBG: in intermedius you can find all features of baltic/graellsii both structural and plumagewise, 'it is worthy its name' (can't express it more sophisticated).

i think there is interbreeding between intermedius and fuscus in southern sweden but jan is the best one to confirm that!

liebers/helbig's "ringspecies" work made clear that smithsonianus/argentatus are different species. and that cachinnans/michahellis are different species. cachinnans is an old species, the "pre-caspian" gull being regarded as ancestor of heuglini, from heuglini derived later probably barabensis by possibly secondary intergradation with southern cachinnans. as for michahellis: it derives from an atlantic glacial refuge versus the aralo-caspic basin refuge of cachinnans. colonization occured from west to east, with armenicus developing to a separate species by isolation.

ok, now that's theory. in general gulls are a good example of the limited accuracy of species definition. it seems that even not so closely related species can produce fertile offspring. it depends of course on which species definition you choose but i think there is a lot to be revealed yet by field+genetic studies.

even more complicated is the situation in the northern pacific and northern canada as xenospiza has pointed out allready. i haven't studied those taxa enough to build up sort of a clear image for myself. similar with taimyrensis/vega/mongolicus etc.

Clearly a work in progress, which has been going on for a rather long time, with different opinions as to how many species the Herring Gull group does comprise, 3, (argentatus, cachinnans and fuscus, or 8-10 (argentatus, armenicus, barabensis (a subspecies of heuglini?), cachinnans, fuscus, heuglini, michahellis, smithsonianus and vegae (mongolicus a subspecies of vegae?) which means of course that the last word isn´t said. In the case of LBBG, is intermedius a valid ssp or not? Although there is no thorough study of the relationship between intermedius and nom. fuscus, the suggestion has been raised that there could be some intergradiation between them since the darkest intermedius are so similar to nom.fuscus. According to some sources no difference in breeding behavior and courtship has been suggested between these, and when comparing mtDNA of nom. fuscus with graellsii there seems to be no significant difference, which suggest that there is a gene flow between these taxa.

The work of Pierre Yésou is interestig (Trends in systematics . Dutdh Birding 24: 2002)

http://www.dutchbirding.nl/

http://findarticles.com/p/articles/mi_qa3793/is_200207/ai_n9133421

http://www.findarticles.com/p/articles/mi_qa3793/is_200504/ai_n13639501

http://ca.geocities.com/kantorilode/Species/HerringGull.html

http://www.birdskorea.org/lwhgid.asp

JanJ

jan (or others): i still haven't read Yésou's basic work (trends in systematics..2002). I don't have dutch birding :C
anyone helping me out with an electronic version of it, sending it by mail?

Different ornithologists seem to have as many opinions as there are ornithologists. The AOU generally considers smithsonianus andargentatus to be one species while the Europeans do not. Klaus Malling and Owens also describe them (as well as Vega) as being closely related. As for the species in the Bearing Sea; firsly Iceland does not occur there. Secondly, Gluacous-Winged Gull seems to be related to everyone! It is close to both Herring and Western Gulls which puts in between two different groups.

Some of the literature that I've read over the years suggest a superspecies between; Herring, Lesser Black-Backed, Yellow-Legged, Great Black-Backed, Western,Glaucous-Winged,Yellow-Footed, Slaty Backed and California Gulls.

Lou,
I don´t know of any electronic version of Yésou.s paper, but easy to order!
(Vol.24:5 (2002) 6 Euro)

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JanJ