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How do birders want species-definition to be determined? Via Morphology, assortative breeding, or DNA analysis? (1 Viewer)

ZanderII

Well-known member
My understanding was that Lesser Redpoll and Common Redpoll do not form mixed pairs where they breed sympatrically (Lifjeld and Bjerke 1996 for example). Has this been contradicted?
 

JWN Andrewes

Poor Judge of Pasta.
OK, so as a sort of thought experiment exercise, say we put aside the paradigm of having a list of species and move instead to that of having a list of recognisable forms; we could call them "ticks" for short.

So how then do we define "ticks"?

Recognisable in the field. As mentioned above this can be a bit of a sliding scale, what with Zino's, Fea's, Desertas Petrels, Crossbills and some others, but that's no different from how things stand now.

Geographically attributable. That sidesteps the whole male vs female debate (slightly tongue on cheek though it is), as well as things like dark & pale phase Skuas, funny looking hybrids feral Rock Doves and Mallards. That promotes cool things to see like Wagtail races,but still leaves things like Bridled Guillemots and Blue Fulmars to argue over down the pub.

Combining these two criteria presents us with anothwr opportunity, which is to embrace some awkward species pairs or groups. If you only get as far as Bean Goose sp, well that's recognisable in the field (as distinct from Pink-footed etc) and geographically attributable (to the combined ranges of Tundra & Taiga). So it's a tick. We you see your first, say, Tundra your list doesn't increase, it just changes slightly.

Any takers?
 

Mysticete

Well-known member
United States
Combining these two criteria presents us with anothwr opportunity, which is to embrace some awkward species pairs or groups. If you only get as far as Bean Goose sp, well that's recognisable in the field (as distinct from Pink-footed etc) and geographically attributable (to the combined ranges of Tundra & Taiga). So it's a tick. We you see your first, say, Tundra your list doesn't increase, it just changes slightly.

Any takers?
I think this is already done by some folks. I know the ABA for a long time has Fea's/Zino's Petrel on their checklist until someone could provide formal documentation and a strong argument that Fea's was the species involved in (most?) sightings.

If all the Crossbills were to be split into call types, I would probably not have a problem with having a "Red Crossbill sp." until I could get something more identifiable.

How do folks treat undescribed species, which don't yet have any name? I would think that is a comparable situation. Do you just not count it at all until it's on a checklist, treat it as a closely related species, or just add it as you would any other bird.
 

Jon.Bryant

Well-known member
Earlier messages suggest that there is a move towards splitting, but surely this is not an intentional objective. Take for instance the fact that prior to 1897 the British race of Willow Tit was unknown to science. Now that birders are aware of the vocal differences in Marsh and Willow, this seems quite mad. But I would argue that we live in a time of better optics, in a time when we can record audio, take high res images, and have better base reference documents, and yes, scientists can also test DNA. Researchers can also travel more easily to far flung parts of the world. I would therefore argue that the more places we travel and the closer we look, the more chance that subtler differences are discovered which lead to splits. It seems less probable that what appeared obvious differences before, should turn out to be erroneous and that species should be lumped. Closer and better scrutiny therefore seems more likely to lead to splits.

In a recent article in the Asian Bird Journal describing changes in taxonomy, I think all the split were supported by differences in morphology (though some differences were small). What I am not sure about is whether the morphological differences were noted and then DNA tested or vice versa. It would seem an expensive option to test everything and hope, but then a lot of species are being discovered in specific areas of biodiversity and diversification.

I think that there are probably very few truly cryptic species - in fact I can’t think of any. The only contender I know of was Red Crossbill, but I recall reading somewhere that Red Crossbill calls can be learnt and changed. None of the current list split Red Crossbill into more than two species, and from what I have read, I understand it is extremely doubtful they ever will.

Earlier messages also suggest that the definition of a species is somewhat arbitrary. I am not totally convinced by this. My understanding is that the process is as follows - a researcher studies a species (say Red Grouse) and proposes in a scientific paper that the research indicates it is a valid species. Taxonomists, working on behalf of global taxonomies (IoC, Birdlife, Clements etc.) then review the published paper and determine whether the evidence is robust enough for acceptance. I presume that the review is made against set criteria, and not just an arbitrary decision, though the criteria are unknown to me and would probably surpass my scientific knowledge.

It would be good if world taxonomies stated their reasons for some decisions, as it may be possible for birders as citizen scientists to be able to close knowledge gaps - are mixed pairs of Arctic and Common Redpoll ever encountered? I hope to visit breeding areas in Norway, so along with many other birders, I could keep my eyes peeled. Birdlife produces a taxonomic notes page, and in some cases they have not accepted a split because acoustic analysis has yet to be completed - as a keen sound recordist, if I know what they want and am off on some far flung holiday, then who knows - I may be able to come up trumps.

One thing is for certain, I think taxonomists are better qualified than I am to make the decision on a species. I wouldn’t have a scooby whether Green-winged Teal should be a subspecies of Common Teal or the two ducks should be separate species. In this example, different taxonomies have reached different conclusions. In fact the three main taxonomies currently are at variance quite significantly across the board, affecting about ten percent of global species. As an individual you could easily spend a lifetime just trying to unravel a small part of your global list. Best just to pick a taxonomic authority and let the experts ponder the issue.

The debate about counting Fea’s/Deserta’s is surely one about listing rather than ornithology/birdwatching. It seems to me it is complicated by the probability of a repeat occurrence. By this I mean we may be miffed if we saw the Avon White or Black-bellied Storm-petrel, as it was probably a once in a lifetime event - one that got way. We would not however be so upset if we had seen an non vocal Mallow Tit, as (provided Willow Tits don’t die out in the UK) it is a fair conclusion that you will in the future encounter both species sufficiently well to tick.

Lists are rather subjective, only an individual knows that they saw a species sufficiently well to ID. I know at national level there is some policing of list and competition, but this can only go so far. As an example I remember twitching a Forster’s Tern at Point of Ayr in 1984. After a very long wait for the tide to turn I eventually found the bird and got other birders on to it - after about 5mins one birder admitted he was not on it, but had said he was because he hadn’t wanted to dip! - not even Lee Evans alleged method of recording who shows at a twitch, could have unravelled such fibbing.

I think global lists are much more arbitrary and to be honest most big listers seem to deal in round numbers (i.e over X,000). Overseas lists are also plagued by lack of experience, and possible errors of judgement. For tours there is the question, did I really see it well enough, or am I just taking the tour leaders word for it?

I actually try to keep records of one’s that got away - flight views of a probable Short-tailed Paradigalla, or just a too distant probable Pom.

I think let taxonomists decide what’s a species, let field ornithologist define what can be safely identified in field guides and ID papers (whether species or subspecies) and let birders and listers record what they feel confident with and happy about!
 

Mysticete

Well-known member
United States
Earlier messages also suggest that the definition of a species is somewhat arbitrary. I am not totally convinced by this. My understanding is that the process is as follows - a researcher studies a species (say Red Grouse) and proposes in a scientific paper that the research indicates it is a valid species. Taxonomists, working on behalf of global taxonomies (IoC, Birdlife, Clements etc.) then review the published paper and determine whether the evidence is robust enough for acceptance. I presume that the review is made against set criteria, and not just an arbitrary decision, though the criteria are unknown to me and would probably surpass my scientific knowledge.
Well, there are two ways species are "arbitrary". One is simply researchers may use different species concepts or even interpret the same concept differently. So often times when people argue about species they may actually be making more philosophical than scientific arguments.

The second element is that there are some general guidelines, but there really isn't a set criteria or quantitative measure to indicate whether something should be lumped or not. And by that I mean, how much interbreeding is allowed? How genetically distinct should something be? How morphologically/vocally distinct? So taxonomic committees have to make judgement calls, usually with less than perfect evidence for either side, and with there own personal biases and gut feelings weighing in on the matter.

The Green-winged/Common Teal is a great example. Both species are largely allopatric, but it's been suggested that they freely interbreed around the Bering Sea. But this isn't a huge region. NACC/Clements considers the morphological similarity and amount of interbreeding as an argument against splitting. Other folks look at the same evidence and recognize the split. This is where we get to the arbitrariness. Although honestly, taxonomic differences between checklists are often far more minor than people give them credit for.

If you want to get a glimpse at the behind the scenes thinking for these matters, the NACC bird checklist for North America posts proposals and voting comments for prior years on their website. You can really get a feel for just how "arbitrary" sometimes these decisions may feel.
 

Jon.Bryant

Well-known member
The example of the NACC is interesting. To be honest I cannot see the advantage of regional committees addressing taxonomy. The BBRC in the UK formally did this, but then decided to switch to the IOC taxonomic list some years ago. I think this move was the correct decision. Most Americans I have spoken to use Clements for global birding, but what happens where NACC varies from Clements at a local level? As with all local taxonomic lists that do not cover all global species, this must get messy.

I am not saying that local taxonomic committees do not have the relevant expertise to make decisions (arbitrary or not), but what is the advantage of investing time (probably voluntarily) and obtaining expertise, to make decisions at a local basis - this seems more about the ‘rules of local listing’, and as I say listing is fairly arbitrary anyway.

There is significant advantage of lumping rather than splitting lists. Think of all the database, reports, books, websites etc. that need to make decisions regarding taxonomy and the taxonomic authority to use. Common use of Latin is also a great communication tool. I once got very confused in China as the name for Ferruginous Duck is Bai Yan Ya, which people with a Beijing accent say as Bai Yar Ya - I was all excited about Baer’s Pochards until we referred to Latin names.

As far as I am aware there are only three global taxonomic lists and for about 90% of birds they match at species level. I understand that moves are afoot to bring about consensus in area of difference. So I would say pick one, ditch any local lists, and hopefully one day we will all be working to the same set of decisions (arbitrary or not).
 

Jon.Bryant

Well-known member
Sorry should have said three global list that are maintained - Clements updated annually, IOC updated biannually and BirdLife updated annually. Howard and Moore, Sibley, Peters etc have not been maintained, with the former the most current and last updated to version 4 in 2013-2014.
 

Farnboro John

Well-known member
Sorry should have said three global list that are maintained - Clements updated annually, IOC updated biannually and BirdLife updated annually. Howard and Moore, Sibley, Peters etc have not been maintained, with the former the most current and last updated to version 4 in 2013-2014.
Should have said BOURC, not BBRC, as well (#52).

John
 

Paul Chapman

Well-known member
Should have said BOURC, not BBRC, as well (#52).

John

Should have said BOU as it was a decision of the BOU rather than BOURC albeit that primarily the BOURC then selected the taxonomy...?


All the best

Paul
 

Mysticete

Well-known member
United States
The example of the NACC is interesting. To be honest I cannot see the advantage of regional committees addressing taxonomy. The BBRC in the UK formally did this, but then decided to switch to the IOC taxonomic list some years ago. I think this move was the correct decision. Most Americans I have spoken to use Clements for global birding, but what happens where NACC varies from Clements at a local level? As with all local taxonomic lists that do not cover all global species, this must get messy.

I am not saying that local taxonomic committees do not have the relevant expertise to make decisions (arbitrary or not), but what is the advantage of investing time (probably voluntarily) and obtaining expertise, to make decisions at a local basis - this seems more about the ‘rules of local listing’, and as I say listing is fairly arbitrary anyway.

There is significant advantage of lumping rather than splitting lists. Think of all the database, reports, books, websites etc. that need to make decisions regarding taxonomy and the taxonomic authority to use. Common use of Latin is also a great communication tool. I once got very confused in China as the name for Ferruginous Duck is Bai Yan Ya, which people with a Beijing accent say as Bai Yar Ya - I was all excited about Baer’s Pochards until we referred to Latin names.

As far as I am aware there are only three global taxonomic lists and for about 90% of birds they match at species level. I understand that moves are afoot to bring about consensus in area of difference. So I would say pick one, ditch any local lists, and hopefully one day we will all be working to the same set of decisions (arbitrary or not).
Well, the NACC/SACC checklist does handle issues beyond taxonomy, including additions to the checklist from vagrants and range expansions. And honestly there is barely any difference between NACC/SACC and Clements. Clements has traditionally almost religiously followed both taxonomic committees. Mostly its a few slight differences in species that are largely vagrants to the New World, and not likely to effect most folks.

Most regions have some sort of taxonomic committee. They may not update as often as NACC and SACC or get as much coverage, but they are still there.
 

Jon.Bryant

Well-known member
I suppose it is possible that Clements copy NACC/SACC but a straightforward copy of NACC/SACC’s homework seems unlikely - unless they share workload by using the same same experts on their panels. An advanced of local taxonomic authorities is smaller workload, so potentially they may review and implement changes quicker than a global taxonomic authority. If Clements later reach the same conclusion as NACC/SACC, rather than merely copy, then perhaps the decision making process is not so arbitrary after all.

The international Ornithological Union has formed a working group to develop a unified world checklist (see Working Group Avian Checklists | International Ornithologists' Union). As you will note in the reference, BirdLife has recently joined the working group, which means that all the main up to date global taxonomies are represented. In recent dialogue with staff at Clements/EBird, it was suggested that an objective of the unified list would be that Clements, BirdLife and IOC would no longer need to maintain their own separate lists. All parties see the advantage that a single unified list would bring to all aspects of ornithology and conservation.

Hopefully local taxonomic committees will also see the advantage and follow suit.
 

Mysticete

Well-known member
United States
I suppose it is possible that Clements copy NACC/SACC but a straightforward copy of NACC/SACC’s homework seems unlikely - unless they share workload by using the same same experts on their panels. An advanced of local taxonomic authorities is smaller workload, so potentially they may review and implement changes quicker than a global taxonomic authority. If Clements later reach the same conclusion as NACC/SACC, rather than merely copy, then perhaps the decision making process is not so arbitrary after all.

The international Ornithological Union has formed a working group to develop a unified world checklist (see Working Group Avian Checklists | International Ornithologists' Union). As you will note in the reference, BirdLife has recently joined the working group, which means that all the main up to date global taxonomies are represented. In recent dialogue with staff at Clements/EBird, it was suggested that an objective of the unified list would be that Clements, BirdLife and IOC would no longer need to maintain their own separate lists. All parties see the advantage that a single unified list would bring to all aspects of ornithology and conservation.

Hopefully local taxonomic committees will also see the advantage and follow suit.
I mean what I am saying is not speculation...Every SACC and NACC decision with only a very few exceptions is followed by Clements. Just look at the update history. Clements, other than the Mexican Duck situation, never has made a North/South American centric split prior to that split being accepted by the NACC or SACC. Even decisions that some would consider controversial (cough rejection of Yellow-rumped Warbler split cough) are followed by Clements.

I applaud the folks behind the new proposal to unify global checklists. I am very curious to see how this plays out from a NA based perspective. The American Birding Association bases their taxonomy around NACC, but includes many ebird users. Ebird will be using the "new" checklist, so will this mean that ABA will have to start following that? How many differences will there be between Ebird and NACC?

I'd say there is about a 1% chance of SACC or NACC going away after the publication of the unified checklist. After all, the work that goes into the proposals probably will save a lot of time for the folks behind the new checklist.
 

Andy Adcock

Well-known member
Cyprus
As far as I am aware there are only three global taxonomic lists and for about 90% of birds they match at species level. I understand that moves are afoot to bring about consensus in area of difference. So I would say pick one, ditch any local lists, and hopefully one day we will all be working to the same set of decisions (arbitrary or not).
I did this years ago when I started using the IOC but it isn't just speciatian decisions which are not standardised, nomenclature is a big issue too as is name changing for apparently political reasons.
 

Jon.Bryant

Well-known member
True - if you don’t like Yellow-billed Loon and prefer Diver etc.

But as long as you reference the Latin, you can call the bird whatever you want in whatever language you like and still be clear what you are talking about. Yesterday I was watching Little Fluff Ducks (Polysticta stelleri) - this English name is a translation from Chinese, but I quite like it, and Chinese is the most commonly spoken language in the world!

I think the concept of standardised English Names is a different issue and a hard nut to crack - ‘gray’ verses ‘grey’, ‘color’ verses ‘colour’ etc would be anathema to birders depending on which side of the pond they live.

Back onto the NACC/SACC, not proposing a coup, but… Birders are not forced to use local taxonomies. If birders switched to a unified global list because of the benefit (say the benefit of recording sightings on various platforms such as EBird or BirdTrack etc.) then local taxonomic authorities would become rather irrelevant. I suspect in some ways this is what has happened to Howard & Moore, which has not been updated since 2014. I therefore think it has lost a lot of its fan base - I don’t know any birders who currently use it. H&M are talking of releasing a version 5, but will it bring the users back? I am doubtful, but we will see.
 

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