LBB gulls and Herring gulls hybridize?

[Amoeba]

Can they?

I just saw a gull and it looked as big as a Herring or LBB gull but it has patches of very dark grey on its back and patches of very light grey. I couldn't tell which it was, but it certainly stood out from the other LBB gulls it was hanging out with. The rest of its body was a brilliant white, so I'm not sure if it could have something to do with its life cycle.

Anyone know?

[Picidae]

Yes they do. See link below.
Surfbirds.com - Hybrid Gulls Breeding in Belgium by Peter Adriaens
However, without providing us with any detailed plumage and especially structure description (cf. to LBBG and HGs you've seen) and without you at least having some reasonably good identification skills enough to rule out alternative gull species, where you are able to separate any confusion species, along with moult strategies of various gulls, you'd be hard pushed to call what you saw as a hybrid. Despite what people think, hybridisation between bird species is not that common. Plumage aberration needs also to be ruled out - it could have been a leucistic LBBG or something entirely different such as Argentatus HG or Yellow Legged Gull with leucistic feathers. (This is where fieldnotes come into their own!)

[Bobbobthebob]

Herring Gulls and Lesser Black-Backed Gulls form a ring species around the northern hemisphere meeting up again in Western Europe. Basically the Herring gull we get here breeds happily with the other sub species of Herring gull types neighbouring it and these hybridize with their neighbours too. This extends right round to Siberia, over the Bering Straits and across North America by which point the bird has become the Lesser Black-Backed Gull. The LBB and the Herring gulls don't seem to readily hybridize with each other. At the same time it's possible for gene flow to occur between the species via their intermediate cousins all the way round the hemisphere. This is why gull taxonomy is so difficult and is subject to change and a fair few arguments.


I'm terrible at gull ID so a proper laridophile can probably point you towards a proper answer.

[Picidae]

Originally Posted by Bobbobthebob

Herring Gulls and Lesser Black-Backed Gulls form a ring species around the northern hemisphere meeting up again in Western Europe. Basically the Herring gull we get here breeds happily with the other sub species of Herring gull types neighbouring it and these hybridize with their neighbours too. This extends right round to Siberia, over the Bering Straits and across North America by which point the bird has become the Lesser Black-Backed Gull. The LBB and the Herring gulls don't seem to readily hybridize with each other. At the same time it's possible for gene flow to occur between the species via their intermediate cousins all the way round the hemisphere. This is why gull taxonomy is so difficult and is subject to change and a fair few arguments.


I'm terrible at gull ID so a proper laridophile can probably point you towards a proper answer.

Bob, do you have a reference for all that information above? From what you appear to be saying, speciation is only down to clinal overlap which isnt true. LBBGs and gulls from the Herring Gull/yellow legged gull complex, are distinct species despite hybridisation being fairly regular in areas where there is clinal overlap.

[Bobbobthebob]

It was something I read in the first chapter of an ecology textbook: Ecology - From Individuals to Ecosystems by Michael Begon, Colin Townsend & John Harper.

Reading back through it, I got the Herring and LBB distribution back to front
It doesn't go into masses of detail as it was mainly using it to illustrate the difficulties in demarcating a species. It states that the LBB gull "originated in Siberia and colonized progressively to the west, forming a chain or cline of different forms, spreading from Siberia to Britain and Iceland. The neighboring forms along the cline are distinctive, but they hybridize readily in nature."

It then talks about how the neighbouring populations are therefore treated only as sub-species. It then gives the same kind of description for the Herring Gull, saying that some of the same orginating stock in Siberia spread East over the Americas eventually reaching a form we call the Herring Gull. And where it overlaps with the LBB gull in Europe they're visually distinctive enough and tend not to hybridize sufficiently that they're deemed to be separate species.

However, having just googled "Herring Gull ring species", it looks like this textbook may have been using an outdated or debunked example. I've got some reading to do!

Darren Naish: Tetrapod Zoology: No no no no NO: the Herring gull is NOT a ring species!

The herring gull complex is not a ring species.

[Picidae]

Thanks for that Bob. Some excellent links.

Perhaps one of the main reasons that the ring species theory is now debunked is down to more extensive studies, better DNA testing, better identification of gulls in the field by a growing body of laridophiles, better optics etc etc

Certainly within the herring gull complex itself, taxonomy is still catching up with newly identified clinal forms of both LBBG and HG, despite relatively recent splits within the yellow legged herring gulls. All very interesting but far too heady for me!

[david156]

Just to confuse matters a bit more, arn't both Yellow-legged Gull and Caspian Gull closely related to both Herring and Lesser Black Backed Gulls?

David

[Picidae]

Originally Posted by david156

Just to confuse matters a bit more, arn't both Yellow-legged Gull and Caspian Gull closely related to both Herring and Lesser Black Backed Gulls?

David

Hi David

LBBG has always been regarded as a species distinct from the Herring Gull complex. However, yes, as you say, Yellow Legged Gull and Caspian Gull, which were originally regarded as belonging to the complex of Herring Gull which included yellow legged type herring gulls, are closely related to Herring Gull (L.argentatus)

There's a discussion here that explains the taxonomy
Caspian Gull
Both Yellow Legged Gull (L.michahellis) and Caspian Gull (L.cachinnans)are now regarded as distinct species from the other Larus white headed gulls.

Further taxonomic considerations suggest that there exists clinal differences between the western and eastern forms of chachinnans some of which have been now regarded as a subspecies of L. fuscus (LBBG).

The taxonomy of WHGs continues to be developed, with often contentious consequences!

(which leads us back to my original point for Amoeba, that you need to be pretty clued up on all of these herring/lesser backed/yellow legged forms in order to recognise a hybrid between any of these when you see one (bearing in mind there's an incredible amount of variation even between individuals of the same species) - beyond nearly all of us, except the most hardened laridophiles that have years of experience of studying these gulls in the field!)