Gull help please (2 Viewers)

Nightranger · Jul 26, 2004

Jane Turner said:
and Ian... you haven't seen enough iffy Scandi Rock pipits or Darrell's Pipit if you don't have an inkling of doubt about Water/Rock/Buff-bellied pipits

Aargh!!!!!! Point taken but I was thinking more about geographical separation in the pipit case of which there is (he says, expecting a barrage of replies) a better case than separating YLG/herring gulls. The genetic study (by my ex-Bangor colleague Stuart Piertney) on the crossbills was enlightening in this respect because the morphology/non-breeding separation of the three species was more marked than the genetic proof. Sheesh! It aint easy this 'ere speciation business. :C

Edward woodwood · Jul 26, 2004

speciation is fairly straightforward if you have criteria you stick to such as the new guidelines by helbig et al. being used by BOU tax. committee or even the 'older' more straight forward concepts such as PSC ESC and BSC. All you have to do is employ them strictly.

The problem comes with birders trying to put a name at species level to everything they see........and premature splitting.

nice to see no one fancies doing the gull above!.......or do they?

Nightranger · Jul 26, 2004

Tim Allwood said:
The problem comes with birders trying to put a name at species level to everything they see........and premature splitting.

nice to see no one fancies doing the gull above!.......or do they?

I couldn't agree with you more. I am not against splitting as such but we have to realise that it is far from easy. The crossbills proved to have less genetic difference than we would expect in most (proven) subspecies yet they are clearly distinct morhpologically if not geographically. The morphological question is tricky especially as classic Linnaean definitions break down with wildfowl because captive escapes do not recognise wild behaviour and hybridise readily. The Aythyas are the worst but they are not the sole villains (this is another argument, albeit less well known against wildlfowl collections). This means we should (but there is no practical way of doing so) consider behaviour along with morphology and geographical separation.

BTW, is that "doing the gull" in the bibilcal sense...LOL?

Jasonbirder · Jul 26, 2004

Don`t genetic distances lag behind morphological differences as birds adapt to changing circumstances? So lack of difference in DNA would only indicate a relatively new species/race wouldn`t it?

Nightranger · Jul 26, 2004

Jasonbirder said:
Don`t genetic distances lag behind morphological differences as birds adapt to changing circumstances? So lack of difference in DNA would only indicate a relatively new species/race wouldn`t it?

In theory that is true especially if we look at chihuahua and Irish wolfhounds to explain how different creatures can be without being a separate species genetically. However, there are examples where other factors are more important and pipits are right in there visually. There is a lot of work to do but many of the issues will not be resolved in the immediate future because they would simply be paper exercises. For instance, it was very important to figure what was going on with 'inland' cormorants as it is for the red grouse work also carried out by Dr Piertney. However, it is not easy to justify the importance of defining YLG and herring gull at this point in time (assuming it hasn't been done) except to bird watchers. Coming back to the point, the greater the genetic differences then the greater the two or more species are from separation [at least that is the initial assumption - Stephen Jay Gould's Punctuated Equilibrium would slightly invalidate this assumption] therefore, the assumption is that crossbills have morphologically, (to a point) geographically and behaviourally relatively recently. However by the converse reasoning we probably cannot say that morphologically similar species are closely related with one of the best (most familiar) examples being chiffchaff-willow warbler (many of the warblers would do for this purpose). Although I have left something out here because voice or song is another aspect (this works for warblers) although chaffinches have regional accents to complicate matters.

Jasonbirder · Jul 26, 2004

Why is it any more important to investigate Red Grouse and Cormorants thatn Gulls?

Edward woodwood · Jul 26, 2004

I believe you can have a certain degree of morphological plasticity in a feature with very little - possibly no - genetic 'change'. Therefore the crossbill morphological diffs may not be indicative of species status and I'm sure they're not.

my favourite bit of DNA-DNA work is that showing new world 'vultures' are actually herons that evolved 'differrently' and that Crab-plover is a Larid rather than a Charadrid (look at a pic and then cover up the legs - it's a gull!)

StevieEvans · Jul 26, 2004

By thes sum cleva lads on eya.
SE

Michael Frankis · Jul 26, 2004

Tim Allwood said:
my favourite bit of DNA-DNA work is that showing new world 'vultures' are actually herons that evolved 'differrently' and that Crab-plover is a Larid rather than a Charadrid (look at a pic and then cover up the legs - it's a gull!)

Storks, not herons

Must try that on a Crab Plover pic . . .

. . . . naah, still looks like an outsize, thick-billed Avocet

Michael

Nightranger · Jul 26, 2004

Jasonbirder said:
Why is it any more important to investigate Red Grouse and Cormorants thatn Gulls?

Commercial interests - sadly, this is still one (or perhaps more so) the driving forces behind research in order to get funding. It is good to know that conservation gets a look-in occasionally in the claim for knowledge but there is always a better angle if there is a commercial aspect (in this case, game management and fisheries respectively). I am not saying that the research was solely driven by those considerations but it certainly helps. Perhaps this is a bit of an over-generalisation but Dr Piertney has lots of potential problems to unravel and it would depend on who wanted to know and whether they could fund the research if you see what I mean.

StevieEvans · Jul 26, 2004

!

Tristan,

I've just Seen a Yellow legged Gull at close range, alongside LBB & HGulls.
I'll send you & Stephen Dunstan some pics of it.

What is the status of YLG ?
Is it a full species ?

Stevie.

Bluetail · Jul 26, 2004

StevieEvans said:
What is the status of YLG ?
Is it a full species ?

Depends who you talk to. The BOURC are still thinking about it.

Binocularface · Jul 26, 2004

StevieEvans said:
Tristan,

I've just Seen a Yellow legged Gull at close range, alongside LBB & HGulls.
I'll send you & Stephen Dunstan some pics of it.

What is the status of YLG ?
Is it a full species ?

Stevie.

Hi Stevie

I look forward to seeing your Yellow-legged Gull pics. Incidently the last gull images I posted to this thread (post 106) are in my opinion a third-fourth year Yellow-legged Gull.

As Bluetail says, Yellow-legged Gull is currently not classed a full species by the BOU but I think this is being reviewed?

Regards
Tristan

Bluetail · Jul 26, 2004

Hi Tristan

Yes, I believe so; but as I understand it the BOURC are (rightly) looking at the whole Herring/Lesser black backed Gull complex before deciding their stance. IMO it would be too blinkered to consider Yelow-legged Gull in isolation.

Edward woodwood · Jul 27, 2004

well spotted on the storks Mr Frankis!

despite the acceptance of a 'standard' guideline for assessing species status, the various European taxonomic committees are not really using yet so decisions are a bit haphazard.

Hence, of the five/people groups who make up the AERC TAC and whose opinions matter in these decisions, four of them (French, Swedes, Germans and Dutch) have accepted the 6-way split of

Herring argentatus and argenteus
American Herring smithsonianus
Eaast Siberian vegae and mongolicus
Caspian cachinnans
Yellow-legged michahellis and atlantis
Armenian armenicus

BOU is pending its decision. There is still a lot of argument as to whether cachinnans and argentatus are species or not as there appears to be extensive hybridisation in Eastern Europe and intermediate calling birds too. Genetic studies, however, show forms are no more closely related than any others.

add in the poorly understood 'Birula's Gull' and things start getting fun....

there....that all makes sense.

Edward woodwood · Jul 27, 2004

wrt to Lesser Black-back Jason

AERC TAC treat it as a single species with graellsii, fuscus, intermedius, hueglini and barabensis as subspecies

some in the AERC TAC want to split into Lesser Black-backed (graellsii, fuscus, intermedius) and Heuglin's (heuglini, taimyrensis, and barabensis)

the dutch have gone further and split Lesser Black back as above into Baltic Gull (fuscus) and Lesser Black-backed (graellsii)
this split is very contentious though.....

Steppe Gull (barabensis) is a future split....?

there, just as clear as Herring picture.....!

Michael Frankis · Jul 27, 2004

Tim Allwood said:
wrt to Lesser Black-back Jason

AERC TAC treat it as a single species with graellsii, fuscus, intermedius, hueglini and barabensis as subspecies

some in the AERC TAC want to split into Lesser Black-backed (graellsii, fuscus, intermedius) and Heuglin's (heuglini, taimyrensis, and barabensis)

the dutch have gone further and split Lesser Black back as above into Baltic Gull (fuscus) and Lesser Black-backed (graellsii)
this split is very contentious though.....

Steppe Gull (barabensis) is a future split....?

there, just as clear as Herring picture.....!

Just to muddy it a bit more, traditionally, heuglini, taimyrensis, and barabensis have been treated as races of Herring . . .

Michael

Bluetail · Jul 27, 2004

Michael Frankis said:
Just to muddy it a bit more, traditionally, heuglini, taimyrensis, and barabensis have been treated as races of Herring . . .

That's precisely what I was thinking, Michael.

I've never been sure of anything with this lot. And what the heck is "Birula's Gull"? - that's a new one on me. As you can tell, I don't do large gulls. I might try to bend what's left of my mind to it when it's all settled down... (If there's a tick in it and all that...

)

Michael Frankis · Jul 27, 2004

I favour lumping all the large white-headed gulls into one species. The applicable species name is the first-named, which is Larus marinus Linnaeus 1758.

i.e., Sea Gull.

:king:

StevieEvans · Jul 27, 2004

Problem solved Michael.
We all owe you.
SE.

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