Convergence of IOC, Clements and BirdLife Taxonomies? (1 Viewer)

[Jon.Bryant]

It is old news that IOC, Clements and BirdLife are all participating in a unified checklist, but there seems to be some evidence that this work is spilling over into the maintenance and update of these three taxonomies.

I have been working on a database, and trying to map the IOC, Clements and BirdLife taxonomies. This process is rather tedious and has occupied much time over the years.

As part of this mapping process I have updated the mapping to include IOC12.2, and the more recently issued Clements 22 and BirdLife 7 lists. Over 500 taxa were modified in Clements 22 and over 400 in BirdLife 7.0. The vast majority of these changes have however been moves towards alignment with one or both of the other lists. The number of complete matches in species concept have increased quite markedly, and it is nice to see some messy issues (e.g. different boundaries for Collared Sparrowhawk/Brown Goshawk & Slate-colored Fox-sparrow/Thick-billed Fox-sparrow) fully or at least partially resolved.

There are however still a few messy alignments remaining (e.g. Dusky Long-tailed Cuckoo Cercococcyx mechowi, treated at monotypic by IOC and Clements, but as two species by BirdLife).

Genus name changes (particular for Hummingbirds in the latest BirdLife checklist) have resulted in an increased number of Latin name matches in all three lists.

The recent changes seem to me somewhat different to previous changes, where my mapping work seemed to indicate increasing divergence rather than convergence in the three lists - generally with IOC making multiple unilateral changes several times each year (now thankfully only twice).

Where the latest Clements and BirdLife changes do not result in full alignment, it seems as if Clements and BirdLife's taxonomy are moving closer. This is not however, an absolute rule and in some cases Clements or BirdLife has followed IOC and not the other list. I have not looked at forthcoming changes in IOC, and it will be interesting to see is version 13.1 moves towards Clements and Birdlife, where the latter two lists now align - IOC is marginally the oldest published list, so it would seem possible that changes adopted by Clements and BirdLife are in the pipeline for IOC.

As I say there are hundreds of minor changes in both Clements and BirdLife, but unilateral changes seem rather limited. At a species level I think these are limited to

• Pternistis atrifrons lumped with Pternistis castaneicollis by Clements
• Gygis candida split from Gygis alba by BirdLife
• Accipiter toussenelii lumped with Accipiter tachiro by Clements
• Nesotriccus incomta split from Nesotriccus murina by Clements
• Nesotriccus maranonica split from Nesotriccus tumbezana by Clements
• Tunchiornis rubrifrons split from Tunchiornis ochraceiceps by BirdLife
• Cyornis kalaoensis split from Cyornis omissus by Clements
• Dicaeum rhodopygiale split from Dicaeum sanguinolentum by BirdLife

As a fan of a unified taxonomic list, it would be nice if collaboration on this work is already starting to nudge the parties closer together, and this become more apparent in future updates.

 

[Mysticete]

IOC has clearly been implementing WGAC related changes for at least the last year, if you go through the updates. And Clements/ebird has stated that the 2022 update would be heavily based on these reconciliation.

What I find intriguing is that, according to the progress the working group has already state, their seems some hesistance is being applied in some manner to North American changes. We know there are some completed groups with differences between IOC and Clements within this region, and IOC hasn't lumped them yet and Clements hasn't split them. So I will be curious to see if they are delaying these changes for some reason (such as delaying conflict between ABA and Ebird), if they are waiting for relevant AOS proposals, or I am just overanalyzing things

 

[Mysticete]

As a specific example of what I am talking about, there is the Spruce-Franklin's Grouse split. This split is not accepted by either Clements, IOC, or NACC. We learned through the NACC bird proposal that was submitted last year that the WGAC voted to accept this split. In fact that was the entire reason why a new proposal was submitted at all. NACC however didn't accept it, and the proposal failed. Now, failure of this proposal to the NACC may have meant it gets another round of votes by the WGAC. Which could explain the lack of change.

But as of now, the split is still recognized by Birdlife, and not recognized by IOC or Clements. Obviously, some list is going to have to change for convergence to happen.

 

[gusasp]

Jon, the tyrants, spurfowl and flycatcher changes are all accepted by IOC for their next update. Among the others, Laridae and the vireos haven’t made it through WGAC, so we could expect some future changes there. The hawk is odd since WGAC does seen to have addressed Accipitridae and still keep them separate.

As for your database, I would recommend the excellent list by Peter Kovalik, found om the IOC website, an up to date comparison of IOC, eBird/Clements, BLI, H&M and others, down to subspecies level. Would save you a lot of work!

 

[Jon.Bryant]

Spruce-Franklin Grouse was only a partial change in the latest lists. Birdlife changed the Genus name only, so that the Latin name for Spruce Grouse is now the same in all lists.

There are plenty of differences that remain in the three lists, where there have been no recent modifications to IOC, Clements or BirdLife. I do take your point however, that quite a few of these differences relate to North America, which is a bit odd - you would think that the species there would be some of the most studied birds in the world! What is missing to make a decision on these birds and can birders in the USA close this knowledge gap?

I hope however, that NACC are not putting the breaks on unifying the world lists. As a birder living on the other side of the pond, I have no idea who NACC are and find it hard to understand why they seem to hold such sway. The U.K. long ago decided to follow IOC, but imagine if every country wanted to stamp their authority on bird taxonomy - surely it would be chaos.

As a birdwatcher who has been lucky enough to bird watch in the seven continents of the world, I would dismiss any partial or localised taxonomy as useless to me. I can see benefit it a unified global list and would therefore also be upset if a regional authority was potentially hampering unification work.

Trying to spark sedition, why don’t US birders take a more global perspective and make NACC an irrelevance?

 

[Jon.Bryant]

As for your database, I would recommend the excellent list by Peter Kovalik, found om the IOC website, an up to date comparison of IOC, eBird/Clements, BLI, H&M and others, down to subspecies level. Would save you a lot of work!

Yes this is a good starting point, but it is not really structured to fit a database. Birdlife’s taxonomic noted and Avibase have also been extremely useful.

I now written programmes, which will recognise all modifications in any of the list and then take the changes and update the mapping. The changes need to be sanity checked prior to being implemented. A bug in the work is that I have started to work on ‘necessary groups’ - i.e the subspecies groups you would need to record to, to be able to map back and forth to a split in another list. These groups are list specific, but can change with modifications to the other list. This makes them quite volatile, so not that user friendly, it is also a bit more tricky to auto generate these groups - especially as a computer program cannot easily distinguish a name change from a split.

I think by the time I crack it, we may have a unified list and I will have waded my time! Oh well.

 

[Mysticete]

Spruce-Franklin Grouse was only a partial change in the latest lists. Birdlife changed the Genus name only, so that the Latin name for Spruce Grouse is now the same in all lists.

There are plenty of differences that remain in the three lists, where there have been no recent modifications to IOC, Clements or BirdLife. I do take your point however, that quite a few of these differences relate to North America, which is a bit odd - you would think that the species there would be some of the most studied birds in the world! What is missing to make a decision on these birds and can birders in the USA close this knowledge gap?

I hope however, that NACC are not putting the breaks on unifying the world lists. As a birder living on the other side of the pond, I have no idea who NACC are and find it hard to understand why they seem to hold such sway. The U.K. long ago decided to follow IOC, but imagine if every country wanted to stamp their authority on bird taxonomy - surely it would be chaos.

As a birdwatcher who has been lucky enough to bird watch in the seven continents of the world, I would dismiss any partial or localised taxonomy as useless to me. I can see benefit it a unified global list and would therefore also be upset if a regional authority was potentially hampering unification work.

Trying to spark sedition, why don’t US birders take a more global perspective and make NACC an irrelevance?

The NACC is a committee in charge of the checklist for North America, and is part of the American Society of Ornithologists, the professional organization for Ornithologists. They are in charge of making annual updates to the official list of birds of this region, and handle not just "splits and lumps" but also higher level taxonomic changes, common names, adding vagrants to the list, and changing other details. Some version of this has been around longer than I have been alive, the major difference being that updates come yearly, rather than every decade or so. Because it's a widely accepted list that's been around forever, the ABA has traditionally followed there decisions in regard to taxonomy, especially as (to be perfectly honest) most birds don't necessarily have the expertise to evaluate the primary literature. Clements as well has more often than not deferred to regional authorities, which in general means they follow AOS for North American based taxonomy. It also should be said that NACC doesn't exist for the sake of birders, and deciding what can or can't be added to a life list is probably viewed with trivial importance by most committee members.

NACC is traditionally viewed as a conservative body. This is in part because of rules they use (Only accepting published data for evaluating splits; strict adherence to the Biological Species Concept), partially because a super-majority of votes are needed to enact a change (which in turns results in a higher degree of evidence than other checklists), and probably also just a matter of the personalities involved.

I'd say most modern birders don't really care about NACC, or for that matter even ABA, as far as lists go. However what has become of increasing importance is ebird, which is part of the WGAC list reconciliation initiative. So I expect if ebird and AOS starts diverging, then we will see potentially see a lower importance given to taxonomic changes enacted by the group, although no doubt their suggestions will still be followed.

 

[Jon.Bryant]

Off on a tangent, but it is interesting why certain splits and lumps have not been resolved in the USA. For example Dutch Birding published an article laying scorn on the decision to lump Thayer's Gull with Iceland Gull (which BirdLife, IOC and Clements have all adopted). The Dutch do have their own taxonomic committee, but I won't do there... The few Dutch Birders I know, don't seem to abide by it anyway...

The argument about Thayer's was basically that little real survey work had been undertaken in the breeding grounds, much scientific argument seemed to cross reference original surveys which was not that robust. Criteria for classifying hybrids were not explained - one survey stated that hybrids were extremely difficult to identify, but that many nests were attended by hybrids pairs, but there was no explanation as to how this was determined.

The breeding grounds would not be the simplest areas to survey, but they did raise two interesting points which could presumably be determined on the wintering ground; namely

1. Large gulls tend to form pair bonds on the wintering grounds. Iceland and Thayer's winter on different coast of the states, so if pair bonds were formed prior to returning to the breeding grounds hybridization should in fact be rare;
2. Vocalisation are possibly different between Thayer's and Iceland Gull, but more sampling was necessary to confirm this.

The two points would appear to be arguments that can be taken forward on the wintering grounds by birders where in particularly Thayer's Gull is relatively common. Iceland may be more difficult, as birds tend to be more pelagic in winter. Are Thayer's forming pair bonds in late winter before departing the wintering grounds? Are long calls different? These calls can frequently be elicited from wintering gulls, particularly during aggression over food.

I have been thinking recently, that it is a shame that differences in taxonomic opinion by any authority, are not supported by a clear explanation for the decision. An explanation concise and clear enough for 'birdwatcher citizen scientist' to understand. With more birdwatchers travelling extensively, it is a great shame that what could be useful observations are generally being lost.

I think at the moment BirdLife possibly come the closest to this in their taxonomic notes, which sometimes say comments that a certain piece of the jigsaw was missing from the taxonomic paper.

 

[Mysticete]

Good news Jon...NACC (and SACC, the South American committee), fully publish there proposals, votes, and reasonings. The proposal for the Thayer's lump and votes can be found here:

2017 Proposals - American Ornithological Society

Proposals 2017-A View Comments 2017-A-1: Split White-faced Ground-Sparrow Melozone cabanisi from Prevost’s Ground-Sparrow Melozone biarcuata – PASSED 2017-A-2: Revise the generic classification of the subfamily Anserinae – PASSED 2017-A-3: Transfer Blue-gray Noddy Procelsterna cerulea to the...

americanornithology.org

Long story short, the study that is the basis of the Thayer's Gull split is now considered rather sketchy and unreliable (e.g., probably faked), and conflicts with other studies which found frequent interbreeding of Thayer's and Iceland.

 

[Paul Clapham]

A bug in the work is that I have started to work on ‘necessary groups’ - i.e the subspecies groups you would need to record to, to be able to map back and forth to a split in another list. These groups are list specific, but can change with modifications to the other list. This makes them quite volatile, so not that user friendly, it is also a bit more tricky to auto generate these groups - especially as a computer program cannot easily distinguish a name change from a split.

I have found that quite often those "necessary groups" are the Clements subspecies groups. So I make them "first-class citizens" in my database, although they aren't species. Yes, they sometimes change over time and they sometimes differ from the actual way that e.g. IOC has made the split; in that case there are more necessary groups to support those changes.

There's also the issue that different lists sometimes break down a species into different sets of subspecies. Then questions arise like "Why does IOC have subspecies X but Clements doesn't" and you find yourself peering at range descriptions for X in IOC to try and find how it's related to the subspecies in Clements. Maybe it's a synonym, maybe it's a split of two subspecies, maybe it's lurking in a different species, and so on. But my database doesn't include subspecies unless they are necessary to explain those differences -- I don't want to do that because I do need to get out of the basement and go out birding sometimes!

 

[Jon.Bryant]

Good news Jon...NACC (and SACC, the South American committee), fully publish there proposals, votes, and reasonings. The proposal for the Thayer's lump and votes can be found here:

Kind of... Just looked at the comments on Thayer's Gull and it is really just a set of comments by each reviewer. In this case the comments are generally that the paper splitting Thayer's Gull as a separate species was inadequate in the first place. I haven't read the source papers but I thought that Thayer's was split from Herring (not Iceland), whereas the comments seem to read as if the old status quo should be restored. One of the reviewers even says 'I have been back and forth on this and remain unconvinced that my Yes vote is the correct one. I could probably still be talked into voting No on this. The problem I have with this is we really do not know what is going on in the Arctic, which is what really matters'. If I was doing the assessment and information was insufficient to demonstrate the new arrangement, I would personally adopt the status quo and reject a new basis to lump the species. Perhaps I am misreading the comments, but I don't think that paper critiquing a previous study, should really be the grounds a reversal of opinion, unless that paper also provides compelling evidence for the proposed arrangement.

What I was really looking for is comments something like;

• Paper demonstrated/failed to demonstrate geographic isolation
• Paper demonstrated/failed to demonstrate area of hybrid breeding and the extent of the hybrid population
• Paper demonstrated/failed to demonstrate morphological differences between the species
• Paper demonstrated/failed to demonstrate vocal differences between the species
• Paper demonstrated/failed to demonstrate extent of clinal variation between the species
• Paper demonstrated/failed to demonstrate variation in habitat selection, which may indicate cryptic specialization by each species
• Paper demonstrated/failed to demonstrate behavioral differences between the species, which may indicate cryptic specialization or breeding isolation
• Paper demonstrated/failed to demonstrate genetic separation, through DNA testing
• etc.

Birders could then possible contribute to resolving some of these points.

I would also argue that from a scientific perspective if comments like the above were raised, then decision would be more easily verified and if necessary reassessed.

 

[Jon.Bryant]

There's also the issue that different lists sometimes break down a species into different sets of subspecies. Then questions arise like "Why does IOC have subspecies X but Clements doesn't" and you find yourself peering at range descriptions for X in IOC to try and find how it's related to the subspecies in Clements. Maybe it's a synonym, maybe it's a split of two subspecies, maybe it's lurking in a different species, and so on. But my database doesn't include subspecies unless they are necessary to explain those differences -- I don't want to do that because I do need to get out of the basement and go out birding sometimes!

I know what you mean, both about the complexity of the groups and getting out of the basement.

There are some truly messy groups. For example Asian Koel is split by BirdLife, but not by IOC or Clements. One of the subspecies is not recognized by IOC as it is synonomized with another subspecies. BirdLife however, recognize both the subspecies and the synonomized subspecies, but places them in separate species. How can you create a group for that unless you extend a list to include unrecognized subspecies, and update range info to facilitate recognition of the faux subspecies?

I have been in contact with the taxonomic panels of IOC, BirdLife and Clements and may send them a list of messy issues from my mapping work. It would seem to me that it is possible that records may currently be falling between the gaps due to these problems with mapping, and therefore perhaps it should be a priority to resolve messy taxonomic issues as soon as possible.

There is probably some merit in adopting the EBird groups and augmenting them where necessary. That said not all EBird groups are necessary - say Goosander (American) and Goosander (Eurasian). I therefore tend to gloss over them when submitting records, which is not so great if I later want to use the data later for mapping to other lists. Perhaps EBird could introduce a 'necessary flag' to highlight where recording to group level has merit based on differences in (maintained and not historic) world taxonomies?

 

[Kirk Roth]

The argument about Thayer's was basically that little real survey work had been undertaken in the breeding grounds, much scientific argument seemed to cross reference original surveys which was not that robust. Criteria for classifying hybrids were not explained - one survey stated that hybrids were extremely difficult to identify, but that many nests were attended by hybrids pairs, but there was no explanation as to how this was determined.

The breeding grounds would not be the simplest areas to survey, but they did raise two interesting points which could presumably be determined on the wintering ground; namely

1. Large gulls tend to form pair bonds on the wintering grounds. Iceland and Thayer's winter on different coast of the states, so if pair bonds were formed prior to returning to the breeding grounds hybridization should in fact be rare;
2. Vocalisation are possibly different between Thayer's and Iceland Gull, but more sampling was necessary to confirm this.

The two points would appear to be arguments that can be taken forward on the wintering grounds by birders where in particularly Thayer's Gull is relatively common. Iceland may be more difficult, as birds tend to be more pelagic in winter. Are Thayer's forming pair bonds in late winter before departing the wintering grounds? Are long calls different? These calls can frequently be elicited from wintering gulls, particularly during aggression over food.

I can weigh in on Thayer's/Kumlein's Iceland Gulls in the Great Lakes region in winter - they are certainly both expected winter species in the same areas and do come into contact. But the bigger issue is that you have to draw a very arbitrary line in plumage color to be able to state that they would "hybridize" - the situation is more akin to integration. As a young birder, I was told that if an adult gull's primaries are more white than gray, it is "Iceland" and if more gray or blackish then it is "Thayer's." The juveniles are similarly on a continuum of pale to medium brown, and it often is a judgement call as well - (again, in practice people seem to make the call based on "more white" vs "more brown.") Iris color is also variable. In general there are darker birds, paler birds, all manner between and the cutoff seems to be whether the plumage is more pale or more dark (while also pretending that sun-bleaching hasn't occurred!). Is this really a valid way to diagnose species? If so, what is our justification of this assumption that the pair bonding questions rest upon? If not, what does that mean for the data we use to investigate this problem?

I don't think most gulls elicit long calls during feeding interactions - the long calls are mostly displays given in standing position (not during activity). Otherwise, I can't speak at all toward vocalizations, but in order to provide an argument for BSC splitting, one would have to 1) establish that there are indeed real differences in vocalization that are related to breeding selection and 2) that those differences are actually correlated to the plumage differences, somewhere along this paleness gradation, that we use to designate "Iceland" vs. "Thayer's." (Otherwise, even if there is mate discrimination based on vocalizations, it would not be correlated to our current plumage-based definitions of the taxa. In other words, if plumage is meaningless, you would have to hear the birds to identify the species!)

One final thing I wanted to mention - based on only about a half dozen pelagic trips on each coast, it seems to me that Thayer's/Iceland Gulls on both sides of North America are no more pelagic than Herring Gulls - in fact, I believe every one I've seen out in the ocean has been in the presence of Herring Gulls. For whatever that is worth.

 

[Mysticete]

Kind of... Just looked at the comments on Thayer's Gull and it is really just a set of comments by each reviewer. In this case the comments are generally that the paper splitting Thayer's Gull as a separate species was inadequate in the first place. I

Did you also look at the proposal that the comments are replying to? I feel that contains some of the questions you are asking about.

 

[Jon.Bryant]

I don't think most gulls elicit long calls during feeding interaction

no more pelagic than Herring Gulls

Yes... a bit of artistic license here.

Long calls are reportedly not unusual in Caspian Gull when they are showing dominance over other gulls in winter. Not sure if this applies to other species. Regarding vocalisation, Dutch Birding states 'Unpublished studies (Peter Adriaens pers comm) ... indicate that kumlieni and glaucoides are vocally similar and that vocalisations of thayeri are deeper and flatter than American Herring Gull, kumleini and glaucoides'. Differences between thayeri and kumleini on the phone app 'Merlin' are readily apparent in their sound and structure of their sonograms (pers obs [M.Ralph Browning])'.

'More pelagic' is a misquote. What Dutch Birding says is 'Typical winter habitat for thayeri is along coats (Weir et al 1995, Howel & Mactavish 2003) and inland valleys (Marshall et al 2003) whereas kumlieni winters in pelagic habitat (Howell & Mactavish 2003).

I am not really for or against thayeri being a species, and this was not my point. I was a bit non plus with Mysticete's suggestion that the NACC could slow down global unification and was pondering why species in the USA are not done and dusted. After all (with the exception of the Canadian Arctic - thayeri was a bad example), we are not talking about a country off the beaten track or rarely visited by birdwatchers and ornithologists.

Interestingly the paper on thayeri seems to be by M.Ralph Browning (retired), Biological Survey at Division of Birds, Smithsonian, Medford, Oregon, USA. So not a Dutchman and sounds like he should be authoritative.

 

[Jon.Bryant]

Did you also look at the proposal that the comments are replying to? I feel that contains some of the questions you are asking about.

No I did not, but I think you misunderstand me. I am not looking to understand why thayeri is lumped, and am not necessarily of the opinion it should be split.

The points I was trying to make were

1. If the decisions of an Authority are to have wide reaching standing, then whoever the taxonomic committee are, it would be good if the scientific reasoning of the committee is clearly documented, so that others can understand their findings, or there is a basis for reassessment at a later time
2. In the case where insufficient information is included in a proposal reviewed by an Committee, then I think this should be clearly stated as a knowledge gap and stated as a reason for rejection of the proposal. There is then direct guidance for others to follow and assist with closing that knowledge gap, regardless of whether this knowledge proves to favors a split of a lump. Whether this knowledge gaps is closed by professional ornithologists or citizen scientists.

With more and more birdwatchers taking photographs, videos and sound recordings, perhaps if we were guided in the right direction, we could help resolve knowledge gaps and allow proposal to be better assessed with fuller information.

 

[Jon.Bryant]

Did you also look at the proposal that the comments are replying to? I feel that contains some of the questions you are asking about.

I have read it now, and it is an odd paper - basically a paper trashing previous works and insinuating a previous studiy were fraudulent.

I found the last paragraph interesting

'We fully agree with the call for further research (AOU 1983). So far, genetic studies on large Larus have failed to reveal consistent differences among taxa much less resolve their relationships, and so that effort awaits refinement of techniques. However, we think that enough data have been published to establish that there is evidence, both direct and indirect, for non-assortative mating between kumlieni and thayeri and that the burden of proof falls squarely on their continued treatment as separate species'.

So basically '... we don't know what is what, but we think there is evidence of hybridization, lets lump them and the burden of proof is on anyone to prove otherwise'. I think if we went by this as a guidance we would probably just have one large gull species - Western and Glaucous-winged Gulls would be one species for starters!

 

[Mysticete]

To be fair...I have heard Western and Glaucous-winged suggested as future lumps.

Personally, I just don't think I get exactly where you are coming from, so I might be abandoning this side track in this thread on Thayer's Gull. IMHO I thought the proposal did a good job of laying out the decision, and it oversimplifies the issue to just reduce it down to "oh well there is hybridization lets lump them". I am someone who often very strongly disagrees with NACC decisions, but I don't in this case, and I haven't heard a whole lot of complaints from birders, at least beyond the initial common gripe of their lifelist going down by one.

And Kirk Roth also I think elaborated on particular issues here, in that birders themselves are often not sure what is and isn't a Thayer's, which is going to hamper ANY research birdwatchers can do. New research is going to have to come from ornithologists working field seasons in the high arctic.

 

[Jon.Bryant]

so I might be abandoning this side track in this thread on Thayer's Gull.

Agreed, I have gone way off course!!! In my first thread, I was really just pleased that there is some evidence that the lists seem to be coming together, prior to issue of a unified list. I was then in a bit in a grump when you suggested this process may possible be being slowed down by a regional authority.

In fact my original feeling of convergence seems to be more than that. I noted a few errors in BirdLife 7 and emailed BirdLife accordingly, so that they can make corrections. I also mentioned my feeling that lists were converging and got the pleasant reply 'Yes, we are working closely with IOC and Cornell to align our checklists as much as possible.'

The small errors I noted were

1. Luscinia svecica Luscinia – The capitalisation of the subspecies name, which is also the Genus name seems wrong. It is considered that the correct entry perhaps should be Luscinia svecica cyanecula, which is omitted from the latest list.
2. Cyornis whitei wihitei should read Cyornis whitei whitei.
3. Therenetes niger niger should read Threnetes niger niger

Cheers

Jon

 

[awiner]

I have read it now, and it is an odd paper - basically a paper trashing previous works and insinuating a previous studiy were fraudulent.

It's not quite just "insinuating", which makes it sound like a nasty personal attack - there's a heavy stack of evidence that the paper that led to its split was entirely fraudulent, based on work that was not done by N. Smith and could not have been done as claimed. (If I remember correctly, one damning detail was heavy pack ice - clearly visible in satellite photos - at the time the author claimed to have rapidly moved from site to site.) It's the modern, larid equivalent of Meinertzhagen's work.

Combine that with subsequent work - which was actually done! - showing non-assortative mating on Baffin Island, and the outcome seems entirely appropriate.