Re-lumping of Common & GW Teal (1 Viewer)

[Zheljko]

Are there other equally dodgy ticks that I should be aware of on grounds that they are genetically too similar to be reliably seen as full species.

I have no idea, but during a field trip in April we saw both Motacilla flava flava and Motacilla flava feldegg males defending territories about "one block" apart (silly measure of length considering that it was open field without buildings, except for a replica of trans-oceanic ship in the middle of field :eek!: and one bird actually sat on top of it for a bit - very nervous, flying away easily). In any case, the beginner birders were initially confused about same species/different species - they have previously seen only one of them and considered it to be the only form in our region.
(colony of White-winged terns was right next to the feldegg's territory :t: )

 

[Farnboro John]

I have no idea, but during a field trip in April we saw both Motacilla flava flava and Motacilla flava feldegg males defending territories about "one block" apart (silly measure of length considering that it was open field without buildings, except for a replica of trans-oceanic ship in the middle of field :eek!: and one bird actually sat on top of it for a bit - very nervous, flying away easily). In any case, the beginner birders were initially confused about same species/different species - they have previously seen only one of them and considered it to be the only form in our region.
(colony of White-winged terns was right next to the feldegg's territory :t: )

So was the feldegg ship assisted?

John

 

[Zheljko]

hmm... I guess flava might have been. Feldegg was to the left, by the tern colony

The site is in an interesting geographic position, at the boundary of districts belonging to Pannonian Plain (flava) and Balkans (feldegg), so both forms appeared.

For me this was a very special experience as I am generally used to "linear" birdwatching (walking along the bank of river so you watch the river as if you watched a museum exhibition on the walls, or walking a forest path). Here all possible birds flew in all possible directions - left, right, toward us, away from us, up, down, diagonally etc.

My friend wrote a blog about this field trip. Be careful as google translate often confuses "was" and "wasn't". http://blog.b92.net/text/22354/SVINJARIJA-OD-PTICARENJA/

 

[MJB]

I think the current treatment of the Fea's group is that there is a different species of petrel in each burrow: many thousands of species. I may be misinterpreting the data of course. John

Damn fine yorker you bowled there, John!:t:
MJB

 

[John o'Sullivan]

I found the earlier thread.

I always saw it as, as many species as islands rather than burrows. But you might be correct.

"I was interested in the paper Richard posted a link to and within this it states

These three populations, thus, represent a case in point where the process of
speciation is currently in progress, and for which unambiguous taxonomic decision is impossible to reach and will depend on species concept (i.e. which character is prioritized)."

This bit "will depend on species concept" is the bit I don't like. The definition of species has become a political issue. The more species you have the more geographical areas you postulate you have to protect.

I don't think it is any co-incidence that a world of conservation also incorporates a trend towards splitting rather than lumping.

Another split I don't trust (without looking at the data) is the Cory's shearwater split.

 

[Mysticete]

Um...please point out where splitting Green-winged/Common Teal has absolutely any affect on conservation of the taxon.

A lot of the current splitting owes more to the development of genetic methods to look at speciation as well as changing ideas on what a species is. Conservation motivated taxonomic change appears to be relatively rare from what I have seen, is often not accepted widely (see: Tigers), and tends to be limited to certain charismatic groups. At least as far as the AOU and SACC is concerned...conservation usually plays no role in whether they reject or accept a taxonomic change.

 

[John o'Sullivan]

Do you think politics and belief systems and practice only operate on one level? Is it only co-incidence that in a world where conservation is promoted as the way forward that "science" moves towards splitting everything as much as possible?

It has no effect on GW-Teal and Common Teal as far as I can see but the move towards splitting not splitting is part of an overall use of "science"to support conservation arguments. If however the Aleutian form was divergent enough to constitutes a seperate "species" then despite the fact that there are lots of GWT and CT conservationists would start insisting that AT needed protecting.

It seems to me that the "standards" for splitting are set as low as possible in order to create as many species as possible. There is then as much to protect as possible.

I'd be more convinced the proposed splits were seperate species if I was convinced that we applied the same standards to Human populations as we do bird populations. When I asked before if we applied the same standards to humans as we do to birds how many species would there be a well-known splitter came back with 7. Some-body else responded BULL and the discussion ended.

There is apparently more genetic variabilty within African human populations than all the rest of the world populations combined yet morphological differences are more extreme on the extremes edges of the population spread from Africa.

If a scientist arrived on Earth and started examining the human populations using the same standards as applied to bird populations would they look at the genetic divergence within Africa and conclude different species? Would they look at e,g, Norwegians and Aboriginal Australians and on morphological/behavioural/verbal differences conclude these were different species?

I believe a species should only be defined when the genetic and morphological and behavioural (including inter-breeding) diferences are particularly significant.

I'm not particularly convinced by Ruddy Duck and WHD, if you put the two populations together they inter-breed and produce fertile offspring, as do geographically isolated human populations when geographical isolation ends. Cultural isolation is often the brake on the human process (at least overtly) but as biological entities humans opulations can all breed with one another.I'm also not particularly convinced by Yellowhammer/Pine Bunting. The hybrid or intergrade zone is too large.


I've just gone back to earleir in this thread and see that there has been some discussion re inter-breeding. Didn't read from the beginning. Perhaps some-one has covered at least some of the above points. John

 

[fugl]

Do you think politics and belief systems and practice only operate on one level? Is it only co-incidence that in a world where conservation is promoted as the way forward that "science" moves towards splitting everything as much as possible?

As always, John, you vastly overrate the influence of the conservation movement. If only you were right!

 

[John o'Sullivan]

The conservation movement influences everything just not as powerfully as it would like. It's not for want of trying though.

 

[Mysticete]

John...most of your comments regarding conservation bear more similarity to the rantings of people convinced of black helicopter and lizard people conspiracies than any sort of rational discourse.

There are other threads here for arguing this. Given that THERE IS ABSOLUTELY NO CONSERVATION BENEFIT TO SPLITTING COMMON TEAL...maybe you could post this stuff elsewhere.

 

[mckaybailey]

John,

I think you're confusing correlation with causation. A lot of my own research involves species-level taxonomic revision, so I'm pretty aware of the bird taxonomy culture. I don't get a sense that the conservation status of a putative taxon enters into the thought process at all (certainly not in the birds I study). A researcher might more likely to study a bird complex with taxa that are of conservation interest as I have done with the Seaside Sparrow, but I think this rarely influences the outcome. For example, just reading the lengthy discussions that the SACC puts on their website, I find it hard to believe that everyone on that committee is also secretly putting a lot of weight on the conservation implications of splits while going to great lengths to avoid mentioning this and coming up with lengthy alternative evidence-based arguments based on other criteria.

I would argue that most splits are being made because new evidence comes to light. Species delimitation is a discovery-based science. Discovery is additive. The number of known rivers, mountains, particles, planets, etc. increases over time. Of course, new evidence can demonstrate that earlier evidence was actually incorrect or bring to light new evidence (e.g. an unknown hybrid zone) that causes us to reassess the weight of total evidence, but generally new evidence reaffirms previous species hypotheses or suggests the presence of new species. Thus, we should expect an overall net increase in species numbers over time with a slow-down as we near the end of the discovery process.

Of course, in the case of species, there is also the issue of species concepts, but, because all the major bird lists have always been based on the biological species concept, I think it would be hard to argue this has been a major reason for the steady increase in all of these list totals over time.

Bailey

 

[John o'Sullivan]

Hi Guys,

I'm deliberately not reading anything above this evening> I don't want to get over stimulated before trying to get some sleep (early start in the morning).

Co-incidentally this thread has been posted
http://www.birdforum.net/showthread.php?p=2899218#post2899218

Doesn't this mean that Pom and Great aren't genetically different and we know Pom is a hybrid any-way. Therefore we all need to untick Pom of our lists?

Also I've only glanced at this thread but some of the gulls aren't genetically seperable using the above bar-coding approach so which gulls do I/we need to untick? Richard??

 

[MJB]

Hi Guys,
Co-incidentally this thread has been posted
http://www.birdforum.net/showthread.php?p=2899218#post2899218

Doesn't this mean that Pom and Great aren't genetically different and we know Pom is a hybrid any-way. Therefore we all need to untick Pom of our lists?

Also I've only glanced at this thread but some of the gulls aren't genetically seperable using the above bar-coding approach so which gulls do I/we need to untick? Richard??

All it says is that the barcode method can identify areas where it alone can't differentiate sufficiently from every sample of Pom and Great Skua.

Barcoding is a useful tool that can indicate where two taxa are sufficiently close genetically (even though they may, through various mechanisms, no longer be able to produce viable offspring) that the limits of the technique can't give you taxa differentiation, although other molecular or morphological analyses usually can.

It can also tell where unexpected genetic divergences may exist in populations, a possible, though not absolute indication of the existence of cryptic (not identifiable by morphology alone) taxa (species or subspecies).
MJB

 

[njlarsen]

Also I've only glanced at this thread but some of the gulls aren't genetically seperable using the above bar-coding approach so which gulls do I/we need to untick? Richard??

Well, you should never make any decisions based only on barcoding. That technique tests only mitochondria, and among the processes that can throw off the results is mitochondrial sweep: a mitochondrion is introduced into a species through a rare hybridization event, and in that species is strongly selected for. It therefore at the population level will replace the mitochondrion that was there before but accompanied with very limited DNA from the nucleus.

Niels

 

[mb1848]

"I don't get a sense that the conservation status of a putative taxon enters into the thought process at all." I believe you and am relieved. But in a slight defense of John O. what I call the dirty hippie biologists eyed subspecies and other taxonomic devices as a useful political tool at a time (70's) where they thought we were headed to environmental biocide. I suggest a reading of a conversation between the late great David Gaines and the late Frank Pitelka in the foreword to the reprinting of the Distribution of the Birds of California Grinnell & Miller. It is nuanced but to boil it down the WWII era biologist Pitelka hates subspecies, thinks its a stupid game that does not matter. Whereas the dirty hippie biologist has a realpolitik view of them as useful idiot taxonomic units.

 

[mckaybailey]

Subspecies are a completely different animal. The subspecies concept is broken for the simple fact that there is no subspecies concept.

Subspecies were defined by Mayr as any population that differs taxonomically from other populations. What does differing "taxonomically" mean? Basically nobody knows, and it has been taken to mean any geographic variation. This led to an explosion of described subspecies that range from highly differentiated allopatric forms to arbitrary divisions of character clines. On paper, these "taxa" look the same, but the differentiated allopatric subspecies are real entities with a shared history whereas the arbitrary divisions of character clines are man-made. I advocate a phylogenetic species concept, so only the former satisfies my concept of a "taxon", whereas I see see no use whatsoever for the latter and spend a lot of my time sniffing these subspecies out and arguing that they should be abandoned.

Although I personally haven't noticed a trend of researchers describing new subspecies to fuel a conservation agenda (though this wouldn't really surprise me), there is, without a doubt, a strong push by the conservation community to retain subspecies that are of conservation concern. The California subspecies of the California Gnatcatcher immediately comes to mind. This "subspecies" is clearly the northern extreme of a phenotypic cline with absolutely no known discrete differences to separate it from any of the other several described subspecies. Yet the U.S. Endangered Species Act includes protection for subspecies, and it has been impossible to get this form off the endangered species list. I understand why, I mean, as geographic variant, it technically fulfills Mayr's requirements for a subspecies. However, I would argue that, while it would be nice to have California Gnatcatchers in California, it is misleading and wrong to list and manage the California population of the California Gnatcatcher as a unique entity, which it clearly is not.

That being said, it is hard to convince some people to abandon a subspecies, regardless of whether or not it is of potential conservation concern. I published a couple of papers a few years ago that clearly showed the three continental "subspecies" of the Yellow-throated Warbler were divisions of character clines in bill length and lore color, yet the latest Handbook of Birds of the World continues to recognize the old taxonomy of three subspecies for no apparent reason. People get attached to these subspecies, and without a major conceptual reevaluation of the subspecies concept, I don't really see anything changing. As long as we have such a vague and unhelpful definition of subspecies, I expect the subspecies category will continue to be a prime target for abuse by conservationist and others.

Bailey

 

[njlarsen]

I have tried to steer away from the philosophical part of this discussion because it has so far only been a repeat of what we have done before. Regarding subspecies, can I remind of this long thread? http://www.birdforum.net/showthread.php?t=168201

Niels

 

[mb1848]

Wow thanks for the great response Bailey. I remember birders being upset and confused about the Yellow-throated Warbler paper. The USA and (I think) European laws about endangered species use a legal and not taxonomic concept of ESU Evolutionary significant unit. But of course it is taxonomic? Thanks Niels for the link to that long thread. It is very useful for this discussion. And it has my favorite post by me on Bird Forum. "The usual anti-progressive forces in North American birding supposedly suppressed it."

 

[mckaybailey]

Wow thanks for the great response Bailey. I remember birders being upset and confused about the Yellow-throated Warbler paper. The USA and (I think) European laws about endangered species use a legal and not taxonomic concept of ESU Evolutionary significant unit. But of course it is taxonomic?

Really? Are you sure we are talking about the same paper? I can't think what would be particularly upsetting or confusing to birders about that paper. I certainly never met anyone who was upset with that work.

The US protects subspecies and ESUs, though ESU is even less clearly defined than subspecies.

 

[Richard Klim]

Birding Frontiers

Garner, Lewington & Lees, Birding Frontiers, 9 Jan 2014: Green-winged Teal – Advanced Identification.