2022-A-1: Reinstate Northwestern Crow Corvus caurinus as a species

NO. I find Slager’s rebuttal convincing as far as the genetic data go. Regardless, I see no evidence for assortative mating that would suggest separate species rank.

NO. This proposal does not present any new data, and I don’t find it convincing with regard to re-splitting Northwestern and American crows. Slager’s comment rebutting the proposed re-split supports the treatment. Although the proposal rightly points out that there are gaps in sampling, I think it’s best to retain the current treatment until additional new data that fill those sampling gaps are published.

NO. There are gaps in the sampling, and It is better to wait for new data that the same proposal recognizes is needed.

NO. Arguments presented justify it being treated as a valid subspecies, not a species. Nothing given on vocal differences, important distinctions in this family. Interesting about the movements in C. brachyrhynchos. Here where I live in the Owens Valley, Inyo County, CA, they are resident in a few major towns, and are rare otherwise, but when they appear, it is in late October-early November, and late March-mid April. Perhaps these reflect the movements from breeders from northwest Canada and, it reflects how migratory some populations are. 

NO. Slager’s Figure 1, showing 18 of 20 BC crows based on nuclear SNPs, is about as convincing a demonstration as I can imagine of pervasive hybridization over a wide area between all-black birds. Thus, I vote no to reinstating C. caurinus as a species.

NO. Given the levels of hybridization where the two forms are in contact, these are best considered subspecies. Details of the extent and nature of the hybrid zone are interesting, and suggest that there might be some mitonuclear discord in gene flow, but do not change the underlying test of species limits where we know they are in contact.

NO. I agree with Slager et al. that examining only the mtDNA data seriously underestimates the degree of hybridization, simply because of the binary nature of mtDNA haplotypes. Even if you ignore the SNIP data and hybridization is only evident over 200 km, the degree of hybridization and the lack of reproductive isolation would still favor treating these as a single species.

NO. The reanalysis presented is based solely on mtDNA, which often exhibits different patterns from the rest of the genome. The ddRAD data clearly show clinal variation in admixture proportions along the BC coast and that there is ample hybridization AND backcrossing in this system, suggesting a lack of reproductive isolation and a single species.

NO. This is an interesting discussion, but I agree with David Slager’s rebuttal to the proposal, pointing out that the reanalysis focuses on the mtDNA data to the exclusion of the SNP data. I do not doubt that additional C. brachyrhynchos genes are being added to the system from these mountain passes, but I don’t think those are the only source of gene flow, and the 900 km coast-wide hybrid zone seems much more likely.

NO. The nuclear SNP data show more widespread hybridization than the mtDNA data alone. Even so, the mtDNA data do indicate hybridization that might still be significant enough to recognize as one species. 

2022-A-2: Recognize Turdus confinis (San Lucas Robin) as a separate species from Turdus migratorius (American Robin)

YES. I continue to believe strongly that confinis is a full species. We’ve got several races of T. migratorius that are not-very-well-marked variations on a theme, and then we’ve got this taxon that is not only just washed out but yellower below, with a longer white unbroken supercilium, a deeper, usually more orange bill, the crown the same color as the back, which isn’t nearly as much paler compared to regular AMRO than are the underparts, the throat very dark-streaked in many (probably males?). So it’s got certain areas of the plumage that are hardly if at all paler, others that are much paler and a different tone, a more different head pattern than generally recognized, and it’s got a more orange bill. Statements that it is just a pale washed-out robin indicate to me a lack of careful inspection of the many readily available photos. In northern Baja, robins don’t look like anything special, but suddenly here in southern Baja the environment has led them to look drastically (in my opinion anyway) different? Why would that be? And wouldn’t we be more likely to see clinality?

There are indeed several songs of confinis on eBird and to me they sound and look on sonagrams distinctly different from any of the (admittedly highly variable) robins from elsewhere in Mexico. I hope everyone will look at this carefully before voting. Yes, a formal analysis is needed, I agree with that, but a quick inspection makes it pretty clear what that will show, in my opinion.

I take issue with using Island Thrush Turdus poliocephalus as an exemplar of the range of morphological variation one might expect within a single species of thrush. It’s long been obvious that there are multiple, likely MANY species in this assemblage, but the published genetic analyses only include a few taxa that aren’t particularly deeply diverged (except the Taiwan Thrush, T. niveiceps, now split). If you listen to songs of various “Island Thrush” taxa on eBird I think you’ll agree that current taxonomy does not reflect true species limits here. The Island Thrush complex was something that was thrown together by Ripley in his 1952 “The Thrushes. A Taxonomic Study. Postilla 13” without any indication of why he took such an inclusive view of this particular “species”, which was basically any Turdus from east of mainland Asia, as opposed to allowing multiple less distinct species to survive on the mainland itself. This paper was the prelude to Ripley’s thrush chapter in Peters (1964).

NO. Reasons are stated in the proposal. Current data are insufficient to make this split with any confidence. This one needs a more thorough study of potential vocal differences.

NO. The proposal gives a strong rationale for maintaining these as subspecies of T. migratorius pending additional data, especially quantitative analyses of song differences.

NO. We need data (molecular, morphometrics, and pattern of color) to support this separation, and the important consideration is that a robust phylogenetic hypothesis of the limits of the species of this complex is needed.

NO. I can’t reach a separate species treatment for this taxon. It is certainly more distinctive than any other subspecies of Turdus migratorius, but is similarly patterned and just looks like a dull and washed out subspecies of T. migratorius. So is there anything else to justify separate species status? The vocal data is all anecdotal and what is presented isn’t at all convincing. I prefer to continue treatment as a subspecies of T. migratorius. 

NO. With essentially no new data other than the Tobias et al. scoring, rehashing existing information doesn’t resolve this case. As with many other proposed Tobias et al. scoring-based splits, this is a case ripe for new work. For now, this seems best as an allopatric subspecies of Turdus migratorius.

NO. I agree with the proposal that a more formal analysis of vocalizations is necessary. The plumage differences are likely not reproductively isolating and may be local adaptations to xeric conditions of south Baja.

NO. While T. confinis is certainly distinct in coloration and bill size to a lesser extent, this may simply be local adaptation and does not translate to reproductive isolation for me. While anecdotal evidence of vocal differences exist, I think this split is premature without more rigorous genetic analyses (not just mtDNA) and quantitative analyses of vocal displays done in the context of other population and subspecies within T. migratorius to determine if the ‘burriness’ described by Howell and Webb is truly different in confinis compared to other nearby subspecies. 

NO. I agree with the proposal that the plumage differences in this case are probably not important, and likely reflect essentially a cline across climate types, this just being the pale extreme in the extreme dry habitat. I also agree that splitting plumage into multiple different scorable characters, especially in this instance, is not appropriate. The vocal differences are intriguing to me, but I agree that a formal analysis and study is needed in this case, preferably with playback experiments.

NO. The plumage differences are pretty dramatic to me, and I agree with another member’s comments who indicated that these are not just “washed out robins”. More pictures are available here: https://search.macaulaylibrary.org/catalog?taxonCode=amerob2&mediaType=p

Nevertheless, more data and analyses on additional characters are needed, especially song and genetics. Even a comprehensive, quantitative analysis of plumage would be helpful. 

2022-A-3a: Treat Turdus plumbeus (Red-legged Thrush) as two species: T. plumbeus and T. ardosiaceus

YES. Genetic data, morphology, and readily apparent vocal differences (which do need to be quantified; Boesman’s note https://birdsoftheworld.org/bow/ornith-notes/JN100310 downplayed the differences, in my opinion) are congruent. I don’t see an argument for keeping them conspecific, other than inertia. Also, please note that a couple of the WGAC no votes were more or less deferring to NACC, not strong votes in opposition.

YES. Among the related New World Turdus (mostly North and Middle American + Caribbean) no taxon shows anything like the phenotypic variation in plumbeus. I really don’t think that comparisons with the distantly related poliocephalus are applicable here. The split is rather deep, vocalization differences are suggested, and it was lumped without comment in the Peters/Bond days.

YES. Although only mtDNA, the split between the two taxa are pretty deep. Coupled with differences in morphology and lack of rationale to lump them in the first place sways me towards voting yes. More genetic sampling (individuals and markers) and rigorous vocal analysis needed. 

NO. Reasons are stated in the proposal. Current data are insufficient to make this split with any confidence. This one needs a more thorough study of potential vocal differences. Degree of divergence at a single neutral locus in insular populations that have likely experienced severe bottlenecks provides exceptionally weak support for species rank. The plumage differences are suggestive but insufficient on their own. In Turdus, it’s all about the voice. All it would take for me to shift to a YES on this would be a more thorough analysis of vocalizations.

NO. Reasons given in the proposal – especially the lack of a thorough quantitative analysis of vocal differences.

NO. We need more data and a formal analysis of the vocalizations.

NO. No, for now, to a two way split, but intriguing. By the way, many refer to eastern and western Cuba for the two subspecies found there. Most (75% or more) of Cuba is occupied by rubripes with an extensive buff belly. In the eastern quarter of Cuba, schistacea is found with grayer underparts, much more like nominate plumbeus from the Bahamas. I believe that both rubripes and certainly plumbeus have been documented with photos from south Florida. 

I am leaning to splitting ardosiaceus and closely allied albiventris from Dominica based on appearance, but especially vocalizations. I have heard plumbeus and especially rubripes sing and it is quite scratchy and the songs are not pleasing to the ear. If ardosiaceus is more melodic that is significant. I guess I would prefer something published detailing the songs, with links to representative songs of each group. That said, I’m open to change on this part of the question, a two-way split. 

NO. With little to support a split other than the Tobias et al. scoring, and the differences heavily based on plumage differences, the case seems woefully unresolved but ripe for new work.

NO. This is a tough call, but I am inclined to maintain them as a single species for now. The longish branch lengths in cyt b are the only genetic data we have; a more rigorous assessment of phylogeographic history would be helpful for this group. Although the plumage differences are substantial, divergence in coloration and patterning can accrue rapidly in Turdidae and is not necessarily indicative of species limits. A quantitative vocal analysis would also be helpful.

NO. Until there is more information on vocal differences, I think it would be premature to split these two taxa.

2022-A-3b: Treat Turdus plumbeus (Red-legged Thrush) as three species: T. plumbeus, T. rubripes, and T. ardosiaceus

NO. Reasons are stated in the proposal. Current data are insufficient to make this split with any confidence. This one needs a more thorough study of potential vocal differences.

NO. Reasons are given in the proposal – especially the lack of a thorough quantitative analysis of vocal differences and the putative broad zone of intergradation.

NO. An analysis of vocalizations is needed, with good support.

NO. As all have commented on, a three-way split is not warranted.

NO. plumbeus + rubripes group are all pretty similar (with intergrading on Cuba) as far as is documented.

NO. With little to support a split other than the Tobias et al. scoring, and the differences heavily based on plumage differences, the case seems woefully unresolved but ripe for new work.

NO. The situation in eastern Cuba needs to be clarified with genetic analyses to see if schistaceus is intermediate between rubripes and plumbeus before such a split could be considered.

NO. Without any additional data, we rely on the qualitative assessments of the Kirkconnell et al. (2020) Birds of Cuba, who suggest a broad contact zone and intergradation between rubripes and plumbeus, suggesting a lack of reproductive isolation. The fact that there may be mimicry adds another layer of complexity to vocal analyses and the possibility of local dialects rather than species identification mechanisms. More rigorous analysis of vocal differences needed.

NO.  Reasons are outlined in the proposal.

NO. Situation on Cuba needs to be resolved. More genetic sampling (individuals and markers) and rigorous vocal analysis needed. 

2022-A-4: Treat Turdus daguae as a separate species from Turdus assimilis (White-throated Thrush)

YES. A bit confusing to follow, but I am marginally persuaded that leaving daguae within T. assimilis for who knows how long, is worse than establishing it now as its own species. I guess we could say under “notes” that its relationship may be closer to T. albicollis (vocalizations). I’m not sure how meaningful the coloration differences are. Vallely and Dyer (2018) hint that the differences may at least be partly the result of color morphs. Vallely, A.C. and D. Dyer. 2018. Birds of Central America. Princeton.

YES. It clearly does not belong with assimilis, both based on mtDNA and song. Morphologically (from inspection of photos) it seems to stand out only by its very well-defined white throat patch, sharply bordered below by the darker breast than in other taxa. Perhaps it could be considered conspecific with albicollis, but the evidence (mtDNA and especially Nacho Areta’s succinct summary from his own experience of the consistency of song of albicollis throughout its vast range vs. the higher-pitched, slower song of daguae, which is borne out by xc recordings) does not strongly support conspecificity, and its range is congruent with a well-known area of endemism.

YES. I think the combination of vocal differences (which are more similar to Turdus albicollis) combine with genetic differences (which place it closer to assimilis though with reasonable distinctiveness). I agree that more data would definitely be preferable, but I think the burden of proof lies on showing that it should be a subspecies of assimilis. What really sells me is the vocal distinctiveness of the group from assimilis.

YES. Although more sampling is desirable, the genetic data that are available show it is much more differentiated than other assimilis species are from each other. Vocal differences argue against including within assimilis as well. Until more data are available, I would be comfortable with separating it from the other two species.

NO. Reasons are stated in the proposal. Current data are insufficient to make this split with any confidence, especially with the current conflict between genetic data and voice. I don’t see the urgency to make a change to the status quo based on mostly anecdotal evaluation of voice and the genetic data that link it to assimilis. Why not wait for a thorough analysis? All it would take for me to shift to YES would be a short paper on voice with adequate N and thorough taxon-sampling.

NO. Reasons are stated in the proposal – especially the lack of a thorough quantitative analysis of vocal differences.

NO. New data and new analyses are needed to support the separation of Turdus daguae from Turdus assimilis.

NO. Convincing evidence on species limits thus far seems equivocal.

NO. This could easily change to a “yes” with an analysis of the vocal differences. In this and the Trogon proposal below, maintaining the status quo is prudent, given the ease with which needed analyses could be completed.

NO. The geographic sampling of daguae is restricted to Ecuador while geographic sampling for T. albicollis is also sparse. The lack of samples from Colombia for daguae is unfortunate as that is where contact may occur with Panama populations. The genetic data are also mtDNA only. The vocal analyses are qualitative and inconclusive, but this would be a great system for a follow-up study.

2022-A-5a: Reassess the taxonomy of the Pampa curvipennis (Wedge-tailed Sabrewing) complex: lump excellens with curvipennis

YES. Its morphometric differentiation seems insufficient by itself to indicate species status.

YES. Great proposal on a complex and perplexing situation that makes my votes tentative and reversible depending on others’ evaluations. I think it would be tough to make a case for species rank for excellens given those genetic data. Then, you add the playback trials, and all that is left is the size difference. No two hummingbird taxa are ranked as species based solely on a slight size difference. 

At the outset, the closely related, similarly dull-plumaged Campylopterus largipennis (in which Pampa formerly resided) has recently been treated as consisting of three species that are parapatric or nearly so in eastern Brazil, with very little morphological differentiation; therefore, the “bar is low” on species limits in sabrewings, in my opinion. However, these three Middle American taxa have no known contact zones and are extremely similar morphologically and vocally. Have they differentiated to the degree associated with species-level differences in other hummingbirds? I don’t think so. The situation with these three taxa seems more like the situation with Campylopterus largipennis in Amazonia: three slightly differentiated, allopatric subspecies.

YES. Difficult case. We have pretty good data on morphometrics and gene flow, and some on vocalizations, but it is still difficult to put these in the context of reproductive isolation. Doesn’t seem like the slight plumage or size difference would be important enough to stop gene flow, and the genetic data somewhat corroborate this. 

YES. There are enough molecular and vocalization data to lump excellens with curvipennis.

YES. This complex really is a borderline case. I am inclined to vote to lump excellens with curvipennis, especially since curvipennis seemed to respond just as strongly to excellens song, but then showed less of a response to pampa. Ideally though, I would like to see more extensive work with playback experiments between both taxa.

YES. Lumping excellens and curvipennis seems prudent given the lack of structure in the mtDNA haplotype network, the shallow divergence between them (614,000 to 202,000 ya estimated as the split), and evidence of some ongoing gene flow. While there are morphometric differences with excellens being larger, these are relatively slight. The differences in song would be expected among allopatric populations with learned song and to me the playback data suggests that curvipennis reacts similarly to curvipennis and excellens songs.

YES. The data suggest these are good subspecies not yet diverged to full biological species level. The genetic data strongly support lumping curvipennis and excellens, while the morphological data indicate continued recognition of subspecies. Playback data are way too overlapping for this to be an effective isolating mechanism in this case for splitting pampa.

YES. Pampa excellens and P. curvipennis are extremely similar in plumage but somewhat differentiated genetically in most analyses of mitochondrial and microsatellite data. Males of excellens appear to have diagnostically longer tails, and this taxon averages larger in other characters such as wing chord and culmen. Songs differ little and playback of songs of excellens to curvipennis and excellens elicited very similar responses. To me, the morphometric and genetic differences provide little indication that these are biological species. In light of this and the relative lack of vocal and plumage differences, I think that these are best treated as subspecies.

NO. Currently excellens is considered a separate species. Given this is a borderline case, might be better to maintain as species. In addition, in my opinion the data presented leans towards separate species: 1) separate genetic clade (although embedded within curvipennis), 2) differentiated in structure plot at k=3, and 3) vocal differences.  

NO. I agree that this is a borderline case, but there are genetic, vocal , and phenotypic differences that set excellens apart from curvipennis. The microsatellite data (k=3) show distinctiveness, at least in the TUX population, with some low level of introgression with curvipennis. The mtDNA haplotype network also shows excellens to be distinct, and the vocal data (pop TUX) form a distinct cluster. Song playbacks don’t show any difference in response, but it doesn’t sound like the experiments were reciprocal so we don’t know how excellens responds to curvipennis songs. Finally, the conclusion that a ‘Yes’ vote would be tentative “pending additional studies in the possible contact area in northern Chiapas (playback experiments and expanded genetic sampling) suggests to me that more work is needed. I prefer to keep the status quo for now.

NO. The treatment of excellens as a distinct species from curvipennis has never really made sense to me, but I tend to favor the status quo unless the data clearly argue otherwise. I think the data presented would not lead us to split excellens, but are borderline, meaning we really need additional data to make a change.

​​NO. I don’t disagree with the tentative recommendations to both parts of this proposal, and I agree that our current treatment of the two species arrangement likely does not best represent what is going on, but I favor a comprehensive solution to the problem. The genetic data on pampa are certainly interesting, but having other substantiating reasons would be helpful, and yes, reciprocal playback. In short, the genetic data should be the impetus for more research. I do agree that Yucatan Sabrewing is a good English name. Howell and Webb (1995) stipulate that the voice and behavior is similar. Regarding excellens Howell and Webb (1995) comments that it is the male that has a markedly longer tail than curvipennis. They map them as nearly parapatric and suggest that field work should concentrate in the Isthmus to determine whether the two taxa breed sympatrically and/or intergrade. While I realize the situation is not satisfactory based on the data, maintaining the status quo seems like the approach to me for now. 

2022-A-5b: Reassess the taxonomy of the Pampa curvipennis (Wedge-tailed Sabrewing) complex: split pampa from curvipennis

YES. I support this treatment based mostly on the strong genetic differences (both mtDNA and microsats) and the playback experiments. 

YES. As noted in the proposal this is a judgment call, but it is clearly morphologically differentiated and is more genetically and vocally distinct than excellens, and occurs in a well-known area of endemism.

YES. Again this is a borderline case, but the genetic (mtDNA, microsats) and vocal data are distinct. The playback experiment results are not very convincing, and the experiment involved playing pampa song to curvipennis but not curvipennis (nor excellens) to pampa. Nonetheless, the available data plus biogeography support that as a reasonable treatment.

YES. There are enough molecular data to split pampa from curvipennis and the allopatric distribution is enough for supporting the split, too.

YES. Given that I voted not to lump excellens, I think I have to support pampa as a distinct species. It is more differentiated than excellens, both genetically and vocally. On English names, I would favor Yucatan Sabrewing for pampa, and I’d probably go for leaving curvipennis as Wedge-tailed Sabrewing. I would be willing to accept the near tautonymic Curve-winged Sabrewing if people think we have to change curvipennis with the removal of pampa.

NO. I don’t support treating pampa as a separate species from curvipennis, but without much conviction. I would say that the playback results are equivocal given that the difference is in the degree of intensity. The genetic data are of no real use in terms of taxon rank in allotaxa (in my opinion), but even so, the degree of differentiation is pretty small.

NO. I don’t think the genetic data really tell us much, if these taxa are allopatric. The vocalization data are interesting, but without reciprocally tested playback data. I don’t think we can assume that vocalizations would be reproductively isolating.

NO. While the genetic data clearly shows strong divergence, I would at least like to see the same playback experiments done with populations of pampa that were done with curvipennis; just because curvipennis shows reduced reaction to pampa song does not mean the same will be true in pampa. The other aspect that could convince me to vote yes would be more discussion of the size difference: pampa looks drastically smaller than the other two subspecies in the specimen line-up, and I would be curious to know how much size variation exists in other hummingbird taxa.

NO. This is a borderline case and I could see arguments made for both sides. While there are morphological differences, the shorter bill length could just be local adaptation or neutral drift. The other morphometric characters have lots of overlap between pampa and curvipennis / excellens. The differences in size look almost clinal with the series of LSUMNS specimen photos provided in the proposal. The vocal displays are rather different and are more so than would be expected by drift alone according to the original study, but I’m not convinced by the playback data that those are acting as strong premating barriers to gene flow. The comparison in the sole playback study was between pampa and curvipennis, which are the most geographically disparate pair within the complex, so perhaps it is not surprising that there is slightly weaker playback response between those taxa. There is also a lot of overlap in the values of their response intensity metric. While there is a deeper mtDNA split and low rates of estimated gene flow between reciprocally monophyletic pampa and curvipennis / excellens that corresponds roughly to mid-Pleistocene (1.4 – 0.56 Ma), this is still a rather shallow divergence and the morphological differences are not sufficient enough to merit an inference of reproductive isolation and separate subspecies status. I think this is best treated as a single species with three subspecies.

NO. The data suggest these are good subspecies not yet diverged to full biological species level. The genetic data strongly support lumping curvipennis and excellens, while the morphological data indicate continued recognition of subspecies. Playback data are way too overlapping for this to be an effective isolating mechanism in this case for splitting pampa.

NO. The genetic data should be a stimulus for more field work and studies in the Yucatan of pampa and to do reciprocal playback. 

NO. These taxa are extremely similar in plumage, and the morphometrics show no diagnostic differences, but they are more differentiated genetically than are excellens and curvipennis. Nevertheless, the genetic differences are not particularly large and do not indicate much regarding species vs subspecies status. Songs are similar and although pampa shows a slightly reduced response to playback of songs of curvipennis, this is not enough to convince me that this is an isolating mechanism.

2022-A-6: Split Haplophaedia assimilis from Greenish Puffleg H. aureliae

YES. Treat as different species to conform to SACC and because of plumage differences that are abrupt and not clinal.

YES. Reasons are stated in the original proposal and the SACC addendum.

YES. This proposal provides sufficient reason to doubt the current two-species treatment, which I’ve never really thought was correct. I see no reason to treat two allopatric hummingbirds as separate species based on leg puff color and slight differences in plumage, and the only reason SACC did so in the beginning was because it started with Dickinson’s (2003) classification, which followed Schuchmann. One of the reasons for splitting is to keep in sync with other treatments, but in my opinion this is only due to the history of the SACC classification and absence of a proposal to lump them.

The two species classification is correct, but not for the reasons given by Schuchmann. The turnover between birds with white in their puffs to those totally buff happens somewhere S of Marañon, much farther south than where Schuchmann et al. placed their nearest point of contact. Further, the change happens abruptly within a region with no obvious physical barriers, which means that they are likely parapatric and thus good species. So, yes, we should maintain two species, but not based on the Schuchmann et al. rationale but on what this investigation has uncovered, which will be more thoroughly explored in the SACC proposal.

YES. This is a tough one for me. I don’t know much about the geography of these taxa, and differences based on puff color and plumage are not sufficient by themselves to argue for species status. However, the turnover without obvious barriers and potential parapatry support a two-species treatment. In any case, I think we should defer to the SACC and treat them as separate species until additional data are forthcoming to suggest otherwise. 

YES. Not only should we follow the SACC and other major lists here, but evidence in the proposal Is even better for recognizing the species split, as assimilis and aureliae types in depto San Martin, Peru, approach one another with dramatic phenotypic turnover in a short distance.

YES. I agree to promote the consolidation of the SACC proposal because there is no published information that refutes it and stability is important when there is no evidence to the contrary.

YES. Wow, what an interesting, and again complex hummingbird situation. It certainly seems as though the affinis specimens at LSU are likely to actually represent cutucuensis, and that the true distribution of affinis is farther south. This would bring NACC not only into agreement with SACC, but with all of the major global checklists. I agree that further taxonomic work is needed for this group to sort out the affinis versus cutucuensis issue, but I agree that is separate from the bigger picture species issue for NACC.

YES. In general, I favor following SACC when the split is extraliminal and it has no effect on names in NACC area as in this case. However, in addition it appears that there is actually pretty good evidence to support treating assimilis and aureliae as distinct species.

YES. Let’s follow SACC’s lead since this is largely a South American taxon, split also supported by other major taxonomic treatments. Available phenotypic evidence evidence suggests introgression is scarce if it happens at all. Would certainly be an interesting group for further phylogeographic study. 

YES. I am reluctant to vote for conformity when there seem to be problems with the basis for which those splits were made post-2000. However, the additional information from the proposal and the SACC proposal, while not published, seem to add to prior evidence for species status.

YES. Excellent sleuthing in determining the geographic limits in South America. And, I agree, follow the SACC lead in the split of the northern taxon, the one occurring in our region.

2022-A-7: Recognize Trogon ambiguus (Coppery-tailed Trogon) as a separate species from Trogon elegans (Elegant Trogon)

YES. This is a tricky decision, as the evidence for lumping these two taxa in the first place seems pretty weak. While I would ideally like to see a more formal analysis of vocal differences between the two taxa, the committee has also considered other cases where we have reversed a seemingly arbitrary lump from years ago (most recently, the split of Comb Duck Sarkidiornis sylvicola and Knob-billed Duck S. melanotos comes to mind, Chesser et al. 2020). So in this case, I am okay with splitting this now, and reinstating the historical names for these two taxa.

NO. Perhaps, given the obvious plumage differences and the possible vocal ones, but given the variability in their songs I’m voting no for now. Yes, the slowest songs are from the elegans group while the fastest ones are from the ambiguus group, but there seems to be overlap, so a proper vocal analysis is needed.

NO. This one just needs a single, thorough analysis of vocalizations that I think will provide sufficient data for the split. I think it could be done using just the recordings available online.

NO. Reasons are given in the proposal – especially the lack of a thorough quantitative analysis of vocal differences.

NO. I prefer to wait for a new evidence, at least, a formal vocalization study.

NO. I find the plumage differences significant, but after listening to the vocalizations of both groups, I wasn’t overwhelmed. As indicated, the speed of delivery of notes in the song varies with members of the same group, perhaps within the same individual, depending on the mood? Perhaps I’m missing the obvious, but I’d like to see the differences detailed in a more formal manner than what I’ve seen so far. 

NO. I am opposed to making this change. Nice contrast with recent evidence for similar plumage differences not causing sufficient reproductive isolation in the sister Trogon rufus.

NO. Given that phenotypic differences in the related T. rufus are not sufficient for reproductive isolation, but that vocal differences are, an analysis of vocal differences is warranted before considering the split

NO. Although the plumages are different and appear diagnosable, there is low genetic divergence and vocalization analyses are lacking.

NO. Formal analysis of vocalizations are needed. Genetic distance/branch length between the two subspecies shown in Dacosta and Klicka similar to that seen among other Trogon subspecies. The plumage differences are interesting, but the proposal points out this type of variation intergrades in other species that come into contact. 

2022-A-8: Treat Lepidocolaptes neglectus as a separate species from L. affinis (Spot-crowned Woodcreeper)

YES. After going through all the recordings myself and becoming convinced that the affinis group must lack the trill song so common with neglectus, I then read Boesman’s analysis, and found that it matched my informal observations closely. It’s hard to believe that a trill song of the affinis group would have simply not been recorded, given the large number of recordings available now and the large number of trill songs among the similar-sized sample of neglectus. This level of vocal divergence does not seem to be mere variations on a theme, but seems likely to be indicative of species limits. Not only do we have this seemingly major difference, but the typical call notes (though variable) seem quite readily distinguished on note shape between the affinis group and neglectus on sonagrams. Also, here is the vocal description from Fagan and Komar (2016, Field Guide to Birds of Northern South America): “calls infrequently. Call is a very thin, rising Tseeeuuu! (similar in quality to call of Rose-throated Becard); also a shorter Tseep! and higher-pitched, thin tseeeeeeeeee.” So, yes, it would be ideal to have hundreds of recordings of each and an in-depth analysis, but it seems hard to dispute that there are major vocal differences between these taxa. The molecular and morphological data are congruent with the vocal data, though much less compelling, and without the vocal data they would not have necessarily suggested specific status.

As for English names, I can live with these especially since a spotted crown is not common among woodcreepers. But if someone suggests something better I’m open to change. 

NO. This one really needs a more thorough, published analysis of vocal differences (if there are any). In my opinion, we shouldn’t base a decision on qualitative assessment of online recordings, especially in woodcreepers.

NO. Reasons are given in the proposal – especially the lack of a thorough, quantitative analysis of vocal differences.

NO. I recommend waiting for new evidence or a new vocalization analysis.

NO. Not yet. With Marantz’s equivocation, I am inclined to await a more formal analysis of all of the calls. Or perhaps, those that are equivocal can respond to Pam’s careful and thoughtful analysis. A better vote might perhaps be “pend” depending on the response. Certainly, there is a large gap between the two groups and the Talamanca region has a high degree of endemism. Separate species to me perhaps might even seem likely. 

NO. Nice proposal. I learned a lot of new things about woodcreeper vocalizations. Thanks for soliciting input from Curtis Marantz; nice to see his insightful comments. Data seem insufficient to split these based on voice, and plumage differences look like subspecies.

NO. It seems strange that the vocalizations in Mexico are so poorly known, given that many areas receive a good bit of traffic from recordists. I think we should heed Marantz’s caution; he has far more experience with woodcreeper vocalizations than anyone, and in the same type of context (drawing species borders). As the proposal states, it does no harm to wait for a more complete analysis of vocalizations, especially in light of the rather underwhelming plumage variation.

NO. This could be a split, but without a rigorous analysis of vocalizations, the comments from Marantz seem our best current assessment. Vocalizations seem variable and combined with the similar overall plumage and relatively shallow genetic divergence suggests to me these are currently better treated as a single species.

NO. Another tricky decision, I was initially leaning toward accepting the proposed split, but after reading Curtis Marantz’s reluctance and comments on extreme variability within populations of woodcreepers, I would like to see more rigorous analyses of the vocalizations of these groups.

NO. Vocalizations are suggestive, but more rigorous analyses are needed. More vocalization analyses, combined with existing molecular data would convince me to vote yes. 

2022-A-9: Recognize Thryothorus albinucha as a separate species from Thryothorus ludovicianus (Carolina Wren)

NO. I am voting against this based on overall similarity, apparent sister species relationship, and similar songs. I’m actually a bit surprised by this, given this particular disjunct distribution, which is not a common pattern.

NO. This one really needs a more thorough analysis of vocal differences (if there are any).

NO. Reasons are given in the proposal – especially the lack of a thorough, quantitative analysis of vocal differences.

NO. New data and new analyses are needed to support this split

NO. I vote against this split given the very similar vocalizations. 

NO. There is no compelling evidence to suggest these are anything more than subspecies, as we currently recognize.

NO. It would be quite difficult to analyze vocal differences given the very large repertoires of both ludovicanus and albinucha. The four cuts in the proposal are quite different from one another, but immediately seem within the Carolina Wren’s range. It seems the plumage differences are not striking either. 

NO. These seem similar in vocalizations, and as pointed out in the proposal the plumage differences seem gradual / clinal with other subspecies in Thryothorus

NO. Reasons are outlined in the proposal.

NO. No evidence presented for this proposed split. 

2022-A-10a: Split Numenius hudsonicus (Hudsonian Curlew) from N. phaeopus (Whimbrel) 

YES. Reasons are stated in the proposal. As I recall, the similarity of vocalizations between hudsonicus and phaeopus was a sticking point the last time we voted (and of course far less genetic data were available), and I’m not aware of a real vocal analysis since then. However, given the consistently high genetic divergence, it seems that having similar vocalizations may be irrelevant to pair formation in this case.

YES. I think there is strong evidence (molecular) for the split, it is very clear.

YES. Part of the discrepancy in views here seems to stem from the ‘degree’ of allopatry between hudsonicus and phaeopus. To me, it seems like they are within range of potential interbreeding with each other. It’s likely that there was more opportunity for interbreeding during glacial periods as well. Yet the level of hybridization / gene flow seems far lower than would be expected given this amount of geographic overlap. Many have cited the lack of vocal evidence for the split, and I agree that this deserves a rigorous analysis with a large sample size for both hudsonicus and phaeopus. My cursory, qualitative assessment of their vocalizations is that they do seem similar, but I suspect there may be some differences in the tempo, average pitch, and structural elements to the vocalizations. Picking vocal differences apart would require a rigorous analysis that has not yet been done. But, to me, given that these taxa are readily identifiable with plumage and do seem to regularly co-occur in parts of Beringea (and probably did more so in recent geologic history), I think these are separate species based largely for now on our genetic evidence of reproductive isolation. 

Macaulay Library phaeopus recordings.

Macaulay Library hudsonicus recordings.

YES. To me, the genetic data seems very compelling for the split, as it suggests extremely low levels of gene flow, and morphological differences are apparent between them (though as noted in the proposal, not necessarily important for shorebird taxonomy). And while they are indeed allopatric on the breeding grounds, I do agree with others that given the extreme dispersal abilities of Whimbrels, the fact that we see such extreme low values of gene flow is important, and not necessarily just a product of their allopatric breeding grounds. While I am still voting in favor of the split, I am also curious about vocal differences, and I agree with other committee members’ comments that this would be worthy of study, but it is not enough to keep me from voting against the split.

YES. Strong genetic evidence is now available to split these taxa which appeared to have been lumped without much justification. There are also morphological differences. However, I do agree with others that vocal analyses would be beneficial.

NO. The proposal omits any comparison of vocalizations, especially call notes, which are highly associated with species limits in Scolopacidae (and Charadriidae) and have constituted part of the basis for assignment of species rank for marginally differentiated species pairs for 7 decades. Besides the classic case of the dowitchers, Old World-New World species pairs that can be identified in the field by call note and which are also treated as species (in some cases due to circular reasoning) are Common/Spotted sandpipers, Gray-tailed/Wandering tattlers, and Common/Wilson’s snipe (the latter recent split based on critical vocal evidence).

As far as I know, Old World-New World whimbrels do not differ in flight/alarm calls, or if they do, it will take a thorough analysis to demonstrate this. Here are Old World Whimbrel calls:

https://www.xeno-canto.org/674552 (by Peter Stronach)

https://www.xeno-canto.org/674527 (also by Peter Stronach)

To my ear, this sounds identical to the standard hudsonicus call. I would immediately yell out “Whimbrel” if I heard this here in the USA. Maybe there are subtle differences, but burden-of-proof in my opinion falls on demonstrating the latter. And of course there is a possibility that actual songs differ as well – again, an analysis is needed. Whimbrels, like other Numenius, have loud complex songs that must certainly play an important role in communication during the breeding season.

This is not to say that calls are “the” mechanism that isolates these shorebird pairs, but what it does say is that by current standards, taxa ranked at the species level have diverged in calls to a level that can be detected readily by casual listening. The absence of thoroughly documented differences in voice was one of the main reasons we did not split the Willet.

The main plumage difference between nominate borealis and hudsonicus is the white area on the lower back. This is almost certainly due to convergent evolution among medium and large shorebirds that spend time together in similar habitats: the Old World taxa have that whitish wedge on the back whereas the New World taxa do not (with the puzzling exception of Limnodromus). So, Eurasian Curlew, Bar-tailed Godwit, Spotted Redshank, Common Redshank, Marsh Sandpiper, and Greenshank all have that similar white wedge pointing into the back, whereas their New World counterparts do not, and this is a widely recognized example of plumage convergence, presumably with adaptive value.

As for genetic data … of course they differ genetically. Most populations with a significant gap in their breeding distributions differ genetically, much less those with phenotypic differences given subspecies rank. I don’t think that tells us much more about species limits than them both having the same number of legs. Comparative genetic divergence data give us an indication of how long populations have been isolated, with an influence of effective population sizes, etc., but they only give us a crude read on species-level differences, which likely have nothing to do with the neutral loci assessed by such a metric. In fact, this was one of the take-homes in my view from Humphries & Winker (2011), not that the taxonomy was necessarily wrong (which would have to be applied also to Pine Grosbeak). Further, to place the comparative genetic data in a proper framework, in my opinion we need to do it the right way, by also considering a broader comparison of shorebird populations with roughly comparable distributions, i.e. paired populations, subspecies, and species; the McLaughlin et al. comparison is anchored at the low end by three paired populations of ducks (notorious for hybridization), and the only other shorebird pair included was the tattlers, which have an Fst value (Fig. 4) roughly twice that of the Whimbrels despite approaching each other more closely in breeding range – apparently parapatric in Siberia (Humphries and Winker; Fig 1f).

As for being “effectively reproductively isolated”, I think that statement is misleading. “Reproductive isolation” in the BSC framework refers strictly to sympatric and parapatric populations, not allopatric populations. All allopatric populations of everything are “effectively reproductively isolated” by geography, and that has no direct bearing on species rank, whether the populations are phenotypically indistinguishable or strongly divergent. That there is any gene flow between populations roughly 1500 km apart actually can be used as evidence for conspecificity because such presumably rare events could be interpreted as an absence of barriers to gene flow. Of course Whimbrels are world-class dispersers, but that’s a double-edge sword – they may travel a long way from home, but they can also presumably get back home with ease (vs. staying around and breeding); that there are 6 named taxa in the complex strongly suggests strong philopatry.

By the way, even HBW/BLI does not split the Whimbrels.

As for the absence of hybrids mentioned in the proposal, unless Gray or McCarthy considered them as separate species, then this doesn’t mean anything. Actually, it wouldn’t mean anything if they did treat them as separate because an occasional hybrid is irrelevant to species rank under any species concept.

As for using putative past contact during other geologic time periods as a reason for taking seriously the current minor genetic differences at neutral loci, this sort of speculation seems dangerous. 

In summary, the proposal claims that “Numenius hudsonicus is a good biological species” based largely on comparisons of genetic divergence. In contrast, I would say there is no evidence that they are good biological species because their distributions are highly allopatric, and because even so they are still apparently occasionally hybridizing, and because there is no phenotypic evidence so far that they have diverged to the level associated with reproductive isolation in shorebirds.

Further, I continue to be dismayed at committee members’ use of genetic distance in allopatric populations as a metric for species rank. There is no objective genetic evidence for species rank unless populations are parapatric or sympatric. Further, are these genetic distances really that impressive? They should at least be put in a formal comparative framework with other Holarctic shorebirds rather than being viewed in a vacuum or compared to ducks. It alarms me that some of us seem to be looking at speciation strictly from the standpoint of degrees of genetic distance rather than taking account differences known to be important impediments to gene flow. Margaret Skeel published two papers back in the 1970s that described and quantified in detail the vocalizations of hudsonicus. This sets the stage for a similar analysis of vocalizations in the Old World taxa. Whimbrels have a complex repertoire during the breeding season including an aerial display that includes singing. Why are we ignoring such important features of their biology?

P.S. After reading the comments of others concerning the significance of possible overlap during the nonbreeding season …. This baffles me. First, we don’t really know how much overlap there is. A record here and there does not constitute widespread nonbreeding sympatry. The populations mostly winter in SEPARATE HEMISPHERES. Even if they were completely sympatric in winter, unless someone produces novel evidence for pairing in winter in Scolopacidae, then any treatment of this as evidence for potential interbreeding is pure speculation. Demonstration of pairing in winter that would entice one member to breed in a different hemisphere a few months later would be a blockbuster discovery. Until such evidence exists, I regard this as special pleading.

I have no emotional stake in the number of Whimbrel species recognized. For all I know, there may be 6 good species, although the Tan et al. data indicate greater similarity among the Palearctic taxa, as would be expected from hemispheric-level biogeography.  I am concerned, however, that any taxonomic change we make in this group would produce the first two “species” of shorebirds NOT known to differ vocally. 

NO. I was going to vote “yes” based on the genetic differences and the lumping without clear justification, but the lack of vocal data and other comments are pushing me to a “no” vote.

NO. I recall voting no twenty years ago and am inclined to do so again, largely along the lines spelled out in other comments. As I recall, I had the same concerns two decades ago. As I run through the species in this family, nearly all have distinctly different vocalizations, except for Calidris ptilocnemis and Calidris maritima. It is plausible to treat those two species as one given the extreme similarity in basic plumage, or just as logically to treat C. ptilocnemis as multiple species, particularly the nominate subspecies. And, given the great geographic variation in size and appearance (and for schinzii and artica molt location and timing) one wonders about multiple species for Calidris alpina, although all may be vocally similar. I think of similar appearing and acting Long-toed Stint (Calidris subminuta) and Least Sandpiper (C. minutilla) and Pectoral (C. melanotos) and Sharp-tailed (C. acuminata) sandpipers, not sister species genetically, and all with distinctively different vocalizations. From what I can read, all of the species within Numenius have their own unique vocalizations. This includes the more poorly known extinct N. borealis and the almost certainly extinct N. tenuirostris. I hear no difference in the calls, the rapid series of piping whistles that we hear in flight. I checked the detailed Shorebirds, an identification guide by Hayman, et al. (1986) and there is no mention of any geographic variation in the vocalizations. The three authors are all experts on this family. 

The motion is built around the strong molecular differences between the two groups and does not discuss vocalizations. There is the matter of the contact calls described above, but what about the bubbling song that is delivered on the breeding grounds, presumably largely/partly in flight displays? If they are identical, one is asked to believe (if advocating two species treatment), that vocalizations are not relevant to pair formation. Really? I have to get a look from the right angle to even see whether there is white up the back to know what subspecies I am seeing from a location that could have either variegatus or hudsonicus (e.g. Gambell on St. Lawrence Island and St. Paul Island in the Pribilof Islands). 

At Gambell, St. Lawrence Island, in the Bering Sea, we see Whimbrels of both subspecies in the spring. They are rare, but fairly regular. Lehman (2019) states that variegatus predominates in the spring, but hudsonicus by 2-1 in the fall. I have had two or more Whimbrels at times in the spring. To respond to another voter’s comment about the distance, that’s some 500 miles from the closest breeding for variegatus (Anadyr), perhaps 200 miles from hudsonicus. Gibson and Byrd (2007) indicate that all records for the Aleutians are of variegatus.

I acknowledge the strong genetic differences and this does give me pause. It would also seem that given the likely mixing of variegatus and hudsonicus in the northern (and central?) Bering Sea region, mixed pairings should be occurring, if non assortative mating is taking place. Perhaps it is the remoteness of the region so they aren’t detected. I note that hudsonicus is recorded from Japan, and there are many records of hudsonicus for the Western Palearctic. 


Gibson, D.D. and G. V. Byrd. 2007. Birds of the Aleutian Islands, Alaska. Series in Ornithol. 1. Nuttall Ornithol. Club and Am. Ornithol. Union. 

Hayman, P., J. Marchant, and T. Prater. 1986. Shorebirds. Princeton University Press. 

Lehman, P.E. 2019. The Birds of Gambell and St. Lawrence Island, Alaska. Studies of Western Birds 4. Western Field Ornithologists.

NO. Like some others, I would prefer to see some breakdown of how reproductive isolation is being maintained, in addition to the genetic analyses. As mentioned, vocalizations in shorebirds are paramount in maintaining (or breaking down) barriers to cross-breeding. Vocal differentiation has been such a strong indicator species status for many shorebird taxa, and it needs to be placed in the equation here. I do not think that wanderings of vagrants tells us very much.

ABSTAIN. In looking at the comments I might clarify that the view of their allopatry is somewhat exaggerated, because some individuals of both taxa also winter occasionally in the wintering ranges of the other one. So they are effectively allopatric-light, i.e., within Mayr’s “cruising range” of each other. It’s extraordinarily unlikely that philopatry alone is solely responsible for levels of gene flow as low as we found. I was surprised that we found gene flow to be so low. In that same paper (McLaughlin et al. 2020) we did not suggest Pine Grosbeaks to be taxonomically miscategorized because they seem to be genuinely allopatric.

With the opportunity for gene flow that the two Whimbrel taxa have, it occurs remarkably infrequently, and it’s been that way for a long period of evolutionary time (many glacial cycles) given how many fixed differences there are in the nuclear genome. No matter how often a particular isolating mechanism appears in a group (e.g., vocalizations in shorebirds), genomic data like these tell us that even if we can’t see what’s causing it, RI is fairly effective. I think we’d be over-reliant on the need for there to be any particular phenotypic trait differences when the genomic data are fairly clear that populations with the opportunity for gene flow are effectively bouncing off of each other in evolutionary time.

The birds overwintering on the wrong side tell us a lot, I think. Because they all head back to breeding grounds together, and either the birds wintering on the wrong continent ignore the onset of breeding in suitable habitat and pass it by to go onto their proper breeding grounds, or inter-population crosses are not as fit as within-taxon offspring. Both could be happening (that would be my guess). From my reading of the literature on these birds, overwintering on the wrong continent on both sides is much more frequent than our gene flow estimates (though I did not quantify wintering casuals/vagrants). These birds are far from achieving strict allopatry at present, and the demographic models indicate that they have been exchanging genes for a very long time without a (model-detectable) period of isolation (i.e., genetically they have apparently never been in strict allopatry). We’re likely in a period of peak allopatry(-light) now, during an interglacial with oceanic separation, but they’ve been experiencing low gene flow through multiple glacial maxima.

Gene flow between these two taxa is as low or lower than that between tattlers (Tringa incana/brevipes) in this same region. The tattlers are presently more parapatric than whimbrels, but unlike the whimbrels they underwent a prolonged period of allopatry before now, as related in McLaughlin et al. (2020).

2022-A-10b & c: Resume using the English name (b) Hudsonian Curlew for N. hudsonicus and (c) Whimbrel for N. phaeopus sensu stricto

NO. I don’t support the use of Hudsonian Curlew vs. Whimbrel, because Hudsonian and Eurasian Whimbrel have been rather widely adopted and are what most living people will already be familiar with. In addition, I’m afraid that the unqualified use of Whimbrel for N. phaeopus s.s. will lead to confusion given the long history of usage of Whimbrel for N. hudsonicus. Also, I think that that goes against our rules for the naming of daughter taxa that don’t have markedly asymmetrical range sizes.

NO. If split, Hudsonian Whimbrel is the way to go so that their close relationship is immediately signaled. Two closely related sister species should not have different “last” names, in my opinion, if possible.

NO. I agree with others that Hudsonian Whimbrel and Eurasian Whimbrel are better names for the reasons given in those comments.

NO. I agree, Hudsonian Whimbrel and Eurasian Whimbrell are better names, and taking care of the committee rules is very important.

NO. I agree with others: Hudsonian Whimbrel and Eurasian Whimbrel. 

NO. I agree with others: Hudsonian Whimbrel and Eurasian Whimbrel. 

NO. I prefer whimbrel for both to facilitate communication.

NO. I agree with others, that Hudsonian Whimbrel and Eurasian Whimbrel should be used if the split passes. 

NO. I would use Hudsonian Whimbrel and Eurasian Whimbrel. 

2022-A-11: Recognize extralimital Leptodon forbesi as a species distinct from Gray-headed Kite L. cayanensis

YES. This conclusion seems inescapable, as evidenced by the unanimous 2007 vote of SACC.

YES. Reasons are stated in the proposal.

YES. Since L. forbesi is extralimital to the NACC region, it’s best to follow the SACC treatment of this taxon as a separate species.

YES. The evidence is clear to the split.

YES. Striking phenotypic differences and unanimous SACC passage make this an easy decision.

YES. The evidence suggests L. forbesi is an allopatric species. 

YES. No reason not to follow others, especially the SACC.

YES. Defer to SACC on largely extralimital taxa.

YES. Reasons are outlined in the proposal, and this brings the NACC in alignment with the SACC.

YES. Clear evidence and following SACC.

2022-A-12: Recognize extralimital Turdus maculirostris as a species distinct from Spectacled Thrush T. nudigenis

YES. Reasons are stated in the proposal.

YES. Since T. maculirostris is extralimital to the NACC region, it’s best to follow the SACC treatment of this taxon as a separate species.

YES. From an NACC viewpoint, I see no reason not to follow SACC treatment.

YES. The difference in eyering is striking, and I don’t think other recognized Turdus species show the same type of difference in eyering width. The difference appears to be highly constant, including in juveniles. The proposal states that vocalizations seem equally similar between this and grayi as with nudigenis, so they don’t seem very helpful.

YES. On the proposal itself I do not find the evidence very compelling that these are good, species-level differences. I am swayed more by the SACC comments, which provide additional insights.

YES. No reason not to follow others, given the different habitats. We should follow the SACC.

YES. Let’s follow the SACC as this is largely extralimital.

YES. I am not convinced by the data presented in the proposal, and would normally vote “no” for this, but given this is a SACC issue, I will vote “yes” to bring the NACC list in alignment with SACC.

YES. Let’s follow the SACC on this. 

NO. I recommend waiting for new molecular data because the available data are not enough to split, and no vocal differences between them.

2022-A-13: Recognize extralimital Sipia palliata as a species distinct from Dull-mantled Antbird S. laemosticta


YES. Songs are diagnosably different and congruent with the ND2 tree. Seemingly the main complicating issue was the possible conspecificity of palliatus with nigricauda, as per the doubts expressed by Donegan, and which would have marginally affected the revisions to our account. However, those were satisfactorily addressed in the extensive discussion of the SACC proposal so this no longer seems to be an issue.

YES. Reasons are stated in the proposal.

YES. Reasons stated in the proposal, and for conformance with the SACC.

YES. There is enough evidence (molecular and vocalizations) and the analyses are good.

YES. For the reasons articulated in the proposal and SACC treatment.

YES. I found the long discussions and new information in the SACC comments to be particularly compelling.

YES. No reason not to follow the SACC. Great analyses of vocal differences, with backup of mtDNA analyses. 

YES. Reasons are outlined in the proposal, and this brings the NACC in alignment with the SACC.

YES. I’m comfortable following SACC on this. 

2022-A-14a: Recognize extralimital Herpsilochmus frater as a species distinct from Rufous-winged Antwren H. rufimarginatus 

YES. This is dictated by the major vocal distinctions that are congruent with morphological groups and seem unsurprising biogeographically.

YES. Reasons are stated in the proposal.

YES. Reasons stated in the proposal, and for conformance with the SACC.

YES. The molecular evidence is convincing and clear, on the other hand there are vocal differentiations.

YES. Fascinating discussion, but SACC treatment should be followed. Nice to see that they have the same problems as NACC in trying to find an appropriate English name. 

YES. I found the lengthy SACC comments to be very useful.

YES. No reason not to follow SACC for this taxon that barely gets into our area.

YES. Follow SACC and other global lists for this well-supported split.

YES. Reasons are outlined in the proposal, and this brings the NACC in alignment with the SACC.

YES. Let’s follow SACC on this. 

2022-A-14b: Change the English name of H. rufimarginatus to Rufous-margined Antwren 

YES. Already adopted in multiple places, appropriate, and mirrors the specific epithet.

YES. The SACC put so much thought and effort into the English names that I think we should assume that the best outcome was reached.

YES. The name fits the species, and this taxon is extralimital so we should go with the name favored by the SACC.

YES. I agree with the SACC proposal, it was worked.

YES. I agree with the eventual settlement of the SACC on English names. 

YES. No reason not to follow the SACC for this taxon that barely gets into our area.

YES. Name fits.

YES. This is an appropriate name. 

YES. Let’s follow the SACC on this.


2022-A-15: Recognize extralimital Pyrocephalus nanus as a species distinct from Vermilion Flycatcher P. rubinus  


YES. It looks like there should be more splitting, especially of the migratory nominate, but further work is necessary first.

YES. Reasons are stated in the proposal.

YES. Reasons are stated in the proposal, and for conformance with the SACC given that this is a South American taxon.

YES. At least this change we need to adopt, two species should be recognized: Galapagos and mainland. I recommend recognizing the four clear species in Vermilion Flycatcher.

YES. This follows the SACC. Tough to deal with a taxon that is likely extinct for a further split. It is a relief that maintaining Vermilion Flycatcher for the northern species is not an issue.

YES. The genetic distance data alone is not compelling, but the phenotypic differences are.

YES. No reason not to follow the SACC, given plumage, size, vocal, and genetic distinctions.

YES. Reasons are outlined in the proposal, and this brings the NACC in alignment with the SACC.

YES. Lots of reasons presented in the proposal to split nanus. Other subspecies might also need species recognition apparently. 

2022-A-16: Change the scientific name of Anthus lutescens (Yellowish Pipit) to Anthus chii

YES. Reasons are stated in the proposal.

YES. Reasons are stated in the proposal. For a proposal on nomenclature, this one is as straightforward as it gets.

YES. The proposal makes it clear that chii has priority.

YES. I recommend the change and Anthus chii has priority. Reasons stated in the proposal.

YES. Reasons are articulated in the proposal. 

YES. This case for priority seems clear.

YES. Clearly necessary by laws of priority.

YES. Priority for chii

YES. The proposal clearly demonstrates it has priority over lutescens, and that the use of chii could not be mistaken for another pipit. Cases like this are fascinating to me, and I love going back to the old literature to figure these things out. It’s like a fun puzzle.

YES. Needs to be corrected due to issues of priority. 

2022-A-17: Revise linear sequence of genera in Troglodytidae, especially Ferminia 

YES. 2 without comment.

YES. Reasons are stated in the proposal, but it would be worth it to have at least one person double-check the sequence presented.

YES. Reasons are stated in the proposal.

YES. It reflects the best phylogenetic data and relationships of Ferminia. Reasons stated in the proposal.

YES. I am trusting others that this is the best linear sequence.

YES. I would not be prepared to sink these genera but I gather that the proposal is simply a rearrangement of the genera, which seems justified.

YES. Clearly necessary by our rules for placing taxa in sequence.

YES. Reasons are laid out in the proposal.

YES. I checked the sequence and it seems fine, although as stated in the proposal, using Fig. 6 would result in a slightly different sequence. 

2022-A-18: Split Leucolia wagneri from L. viridifrons (Green-fronted Hummingbird)

YES. Another tough one to put into the context of reproductive isolation. At least wagneri differs in a rather striking manner. Given the propensity of hummingbirds to use less distinctive plumage differences to be reproductively isolated (e.g., color of gorget iridescence), I think the cinnamon sides would be important in species isolation if in sympatry.

NO. Genetic data do not indicate separate lineages. Only differences appear to be plumage differences and, given the contradictory evidence from other data sets, I would argue that the plumage data alone are insufficient to warrant a split.

NO. The genetic analyses to date and the similarity in vocalizations with viridifrons do not support this treatment, despite their being relatively well-marked morphologically. Instead, it appears that villadai is a candidate for species status, despite being long overlooked and only described in 2000. 

If the previously suggested evidence for sympatric breeding between wagneri and villadai is forthcoming, that would seem to further support the specific distinctness of villadai. More data on levels of intergradation and width of the hybrid zone between viridifrons and wagneri might change the picture (as for example with the streamertails) but until then the evidence leans toward keeping them lumped. It also calls into question the specific distinctness of viridifrons.

NO. I don’t support this for all the reasons outlined in the proposal (which is an outstanding collation and synopsis of all available information). Instead, it appears that there are more reasons to recognize villadai as a species than wagneri, and I think a pruned, subsequent proposal on that issue would be a good idea. I would caution that evidence of sympatry in hummingbirds has to be evaluated with care – I suspect the vast majority of non-hermit hummingbirds show seasonal movements.

NO. This proposal is a great summary of the available data, and I agree with the conclusion that treatment of wagneri as a separate species is not warranted at this time.

NO. It needs better molecular data and analysis of the coloration pattern.

NO. Another complex hummingbird situation, the taxonomy of this genus is very messy with respect to violiceps and viridifrons. For the time being, I am going to vote against splitting wagneri from viridifrons, at least until more work can be done. It is intriguing that very few intermediates are known, but that only would be important if there was any area of known sympatry, which currently it appears there is none. The extensive genetic admixture would suggest recent introgression, though I am not convinced the STRUCTURE plot necessarily shows admixture or just an inability to discern structure based on the few genetic markers. This could easily be a situation where genetic differentiation is very low with incomplete lineage sorting, but the strong (relatively) morphological differences confer reproductive isolation. I think the key question is whether these plumage differences are displayed in any way during courtship, such that females could distinguish between taxa. It seems that very little is known about the courtship displays of this genus.

NO. The plumage differences that wagneri shows are suggestive, but it does not stand out as a genetic unit. Given that, I am not inclined at present to split wagneri, but a clearer picture of distributions, displays, and hybridization might change that.

NO. Collectively, the data suggest that wagleri is a subspecies. Nice proposal on a complex group.

NO. Excellent proposal. To me, there is either substantial incomplete lineage sorting, gene flow between the putative species, or both to an extent that precludes me from thinking of them as separate species. With more genomic data and geographic sampling, we may find that there really is little gene flow and they are reproductively isolated, but with what we have at hand, wagneri seems better treated as a subspecies than a full species.

NO. Utterly fascinating! All eyes should now turn to the study of villadai as the proposal suggests and members have commented on. 

2022-A-19: Split Black-billed Streamertail Trochilus scitulus from (Red-billed) Streamertail T. polytmus

YES. I went back and forth on this one, but under the assumption that birds mate assortatively by bill color, the case can be made that these are two biological species. But because of the lack of genetic divergence broadly across the genome, I would feel more comfortable about this if the courtship differences were better documented.

I vote to split T. scitulus from T. polytmus, based largely on the very narrow and stable hybrid zone. In addition, del Hoyo and Collar mention vocal and display differences, and Kirwan et al. adopted this split in Birds of the West Indies (2019).

YES. Clearly there must be an extreme barrier to gene flow for these two to maintain those strong phenotypic differences while in direct contact. That they are poorly differentiated at neutral loci in my opinion is irrelevant. The overwhelming signal from the distribution of phenotypes is that there is no free-interbreeding between the two and that gene flow is insignificant — otherwise, the contact zone would look very different, i.e. an area where only intermediate bill colors and bill shapes could be found.

I have subsequently discussed this extensively with Gary Graves and Robb Brumfield, both of whom think that the two taxa behave as species and that the lack of broad differentiation is due to the recency of the split. As Gary emphasized, if there weren’t barriers to gene flow, then scitulus with its tiny range would have been swamped right off the island. Yet it maintains its phenotypic distinctiveness.

To me, the scenario that best fits the empirical description of the contact zone is that these are two recently diverged populations with only slight genetic differences accumulated so far, but those differences are critical ones. Bill color can easily be envisioned as a reproductive isolating mechanism, and mate discrimination is so strong that there is surprisingly little evidence of active gene flow, especially for a highly promiscuous species like a hummingbird. The width of the hybrid zone is narrower than the daily potential cruising range of a hummingbird. This is likely the most abrupt transition from one species to another documented so far in which at least some hybridization has been documented. Note that bill color is often associated with species-level differences in related genera such as Chlorostilbon in the same tribe (Trochilini) — Stiles (1996 Wilson Bull.; description of C. lucidus) noted the somewhat mosaic pattern in black- vs. red-billed Chlorostilbon species. Also, it’s not just bill color but also a slight difference in bill shape — narrower in black-billed. Further, Schuchmann (1978) stated that he found differences in display and vocalizations between the two in his aviaries. Schuchmann may know more about hummingbirds in captivity than anyone in the world, so although he did not quantify these differences, I think we need to treat that seriously. We don’t even have such descriptions to fortify species rank for many allotaxa in hummingbirds we treat as species.

YES. The proposal presents a good case that strong selection must be acting on these populations to keep them phenotypically divergent. The apparent stability of the hybrid zone, steep and coincident clines based on bill color and genetics, and supposed vocal and display differences (though not quantified), all support a two-species treatment.

YES. Aside from the genetic results, all signs point to some sort of selective bias towards mating between birds with the same bill color, or selection against hybrids, or both. The temporal stability of such a narrow hybrid zone is a good indicator that these are acting as good species, albeit with limited gene flow between them.

YES. The proposal is good.

YES. The extremely narrow nature of the phenotypic hybrid zone, which is coincident with the most divergent loci, is compelling in suggesting that selection is very strong in this case. If there was truly no selection, then the hybrid zone would not be narrow and stable over the approximately 50 years that it has been observed. It is also not uncommon in hybrid zone studies to focus on introgression patterns in highly divergent loci, and it is expected that some, and possibly only very few, will show steep clines (e.g., Barton and Gale 1993, Larson et al. 2014). While we don’t know how far streamertails are capable of dispersing, even if we assume an extremely small distance of 180 m (based on how far pollen was found to be transported by another Caribbean hummingbird), a hybrid zone this narrow would only have formed 24 years ago if there was no selection, while we know this one has existed at least 50+ years. Further, even though Graves (2015) found two sites which were dominated by hybrids, the sample sizes at these sites were small, and this is not unusual to find in hybrid zones. In many well-studied avian hybrid zones, hybrids may outnumber parentals or form a significant proportion of the population within the core of the hybrid zone, despite strong selection and reproductive isolation (e.g., chickadees, Taylor et al. 2014; orioles, Walsh et al. 2020). This does not mean that the barriers to reproductive isolation are ineffective, but could be the result of density differences within the hybrid zone (e.g., Barton and Hewitt 1989), where parentals may be rare within the core of the hybrid zone. 

YES. The proposal provides strong evidence to split the two Streamertails despite some hybridization occurring.

NO. Under the biological species concept these are subspecies with a parapatric hybrid zone due to strong divergent selection. Hybridization is likely keeping most of the genomes homogeneous (Graves 2015: table 1 shows two localities with high levels of hybrids). These types of clines representing steep selection gradients seem uncommon in birds, but are well known in other animals, e.g., white sands lizards, insect ecotypes. It is adaptation and a very interesting type of divergence, not to be confused with species-level divergence (under the BSC). The fact that “they do not form a freely and randomly breeding population” is not a supportable species limits criterion, because assortative mating has to be much, much more than simply present to be an effective isolating mechanism. Strong divergent selection on a few loci is an important part of the initial stages of speciation but not a sufficient condition for full biological species. Additional thoughts from email exchanges: 1) Lack of free interbreeding = assortative mating from 51% to pushing 100%. Most of that space is irrelevant for species limits, because without other reproductive isolating mechanisms it produces too much gene flow. It’s probably only when you get near 98-99% that it becomes really effective. Presence alone means nothing. 2) We can’t just tally up Graves’ table 1 as supporting strong assortative mating, because most of those localities don’t involve a behavioral choice, due to distance and dispersal limitations. At two localities where birds apparently do have a choice, they seem to be doing rather poorly, with 100% and 66% hybrids in those populations. Yes, sample sizes are small, but both samples suggest there are a lot of hybrids where the two forms meet. This makes the genomic homogeneity no surprise but gives us more information about its degree. If there were no hybrids found, then homogeneity might mean recency, but in the presence of hybrids gene flow is the most likely evolutionary reason. 3) We can talk about differences in bill color, display, and song all day, but the existence of those differences is apparently not sufficient to lower gene flow sufficiently beyond a few loci to achieve essential independence of species lineages. How much of the genome not crossing hybrid zones are we willing to call species? At some point such adaptation does equal species, but I’d like to see a lot more population-level genetic variation being involved. Here we have just 0.38% (23/6000) of the surveyed genetic variation segregating showing significant differences.

NO. Although hybrids based on phenotypes seem to be rare and the hybrid zone is stable and narrow (at least in terms of bill color), the genomic data to me suggest a lack of reproductive isolation. This could be a situation where there is a small number of loci of large effect that underlie bill coloration and that phenotype in turn dictates assortative mating. However, in my opinion, pre-mating isolation has not been demonstrated as rigorously in the streamertails as other systems with similar dynamics, such as capuchino seedeaters (Sporophila). In my opinion, the genetic cline analysis presented here is circular reasoning and cannot be submitted as evidence of a lack of hybridization or gene flow between species. Those 23 SNPs were hand picked because they had high allele frequency differences between the red and black bill morphs, so of course a cline constructed from those few outlier taxa will be steep and narrow, but that does not suggest that hybridization and gene flow is infrequent or absent. Rather, the data to me suggest that much of the genome is free to exchange between red-billed and black-billed streamertails. We need more rigorous demographic analyses that compare models of no ongoing gene flow and ILS vs models with ongoing gene flow, which should be possible with GBS data. If there were stronger *quantitative* (rather than anecdotal) evidence for assortative mating in the contact zone I would be more inclined to vote yes, but the genomic data really suggest a single species to me with geographic variation in bill color. With the data and analyses we have on hand, I think it is more likely that there is ongoing gene flow and these should be subspecies not full species under the BSC.

NO. As I thought about this issue for much of yesterday, I kept thinking of the situation with Yellow-rumped Warblers (Myrtle and Audubon’s). They are seemingly distinct on many characters, but where they come narrowly into contact, there is (apparently) no assortative mating. Isn’t that what appears to be going on with the streamertails as is suggested by some members’ comments? I’ve seen both taxa and they certainly seemed distinctive based on bill color alone, but that character alone isn’t enough to prevent very widespread hybridization in the narrow zone of contact. Perhaps more exhaustive field study would more accurately determine the degree of hybridization. Has the NACC ever determined what percent is acceptable? Despite other taxonomic treatments of this pair, I am inclined to treat these two as well marked subspecies. Additional studies should look for different vocalizations and displays too in addition to phenotypic characters and genetics. 

2022-A-20a: Split Cynanthus latirostris (Broad-billed Hummingbird) into three species: split doubledayi from latirostris

YES. The topology of the phylogeny requires splitting doubledayi and latirostris (doubledayi closely related to a different species)

YES. I vote to split doubledayi, which has evidently been wrongly included in C. latirostris all along.

YES. Treating doubledayi as a separate species is required by the phylogeny.

YES. This is straightforward based on the molecular data. 

YES. The phylogenetic position of doubledayi, sister to auriceps and not to latirostris (ss), strongly suggests that doubledayi should not be included with latirostris. Also, the plumage, and to lesser extent size, differences are likely reproductively isolating within this complex.

YES. There is clearly a relationship between C. doubledayi with C. auriceps and not to latirostris.

YES. Reasons are outlined in the proposal.

YES. The phylogenetic data are clear. Also plumage and size differences are consistent with a split.

YES. Genetic and plumage data support splitting doubledayi from latirostris, as of course does their sympatry. 

YES. Splitting doubledayi from latirostris makes sense as the species is polyphyletic as currently defined. Also, they appear to maintain phenotypic distinctiveness when they occur together. 

YES. Given the sister species relationship, this is warranted. I was not struck by anything dramatic (from Broad-billed) when I viewed this taxon in the field. I wonder if there are any vocal differences. Howell and Webb (1995) don’t suggest any. 

2022-A-20b: Split Cynanthus latirostris (Broad-billed Hummingbird) into three species: split lawrencei from latirostris


YES. I would argue the genetic data and topology of the phylogeny are sufficient to split this island taxa as a full species. 

YES. C. lawrencei is much more of a judgment call, but with a 2.15 mya divergence time and the morphological differences described by Ridgway, in my view it is better treated as a species than a subspecies of C. latirostris.

YES. The evidence here is much weaker, obviously, but a difference in throat color in this group could be interpreted as a “major” difference in the comparative framework of weakly differentiated species in the Chlorostilbon-and-relatives lineage, and throat color could be important in mate choice. Using that framework, perhaps burden-of-proof would be on treatment as conspecific. Howell & Webb (1995) noted that they had formerly been treated as conspecific and that they differed in throat color and to some degree in tail furcation, but did not address species limits directly.

YES. This split is less clearcut, but phenotypic and genetic differences (albeit relatively weak) combined with the divergence time which is greater than other island taxa treated as species (forficatus) convince me that C. lawrencei is best treated as a species.

YES. Even more important than the genetic divergence, which appears significant, the green throat of lawrencei would likely be reproductively isolating. 

YES. Even though lawrencei is clearly sister to latirostris, and closely related, the proposal notes that the divergence time is longer than another species pair that NACC recognizes in the same genus, plus the morphological differences between lawrencei and latirostris seem relatively quite strong in this clade of very similar looking species, with clear distinguishable differences in plumage (much greener in lawrencei) and size (much smaller in lawrencei).

YES. Fairly long divergence time genetically and significant plumage difference,

YES. While the genetic differences are slight, I like the idea of striving for consistency in taxonomy by splitting lawrencii from latirostris if we are to recognize forficatus and canivetii. Also, given how phenotypically conserved Cyanthus hummingbirds are generally, the difference in throat color for lawrencii from mainland latirostris seems relevant. 

YES. Genetic studies cited in Dickinson and Remsen (2013) indicate that Cynanthus is firmly embedded in Chlorostilbon, and I believe that was the impetus for Kimball Garrett’s motion to change the English names of members of this genus to “Emeralds.” Species limits within Chlorostilbon appear generous with the splitting of the various West Indian species as full species, and C. forficatus from Cozumel Island as a full species. The taxon from New Providence is represented by a single specimen. The differences with the Tres Marias taxon, lawrencei seem comparably about as different. I guess one could ask why make a difference with this allopatric islands taxon from the others? 

NO. While lawrencii might be a phylogenetic species, as an isolate on the Tres Marias it seems better considered a subspecies of latirostris. Divergence times are not reliable indicators of species limits; divergent selection is far more important.

2022-A-20c: Split Cynanthus latirostris (Broad-billed Hummingbird) into three species: English names

YES. The proposed English names are fine and straightforward. 

YES. I agree with each of the English names suggested in the proposal.

YES. With doubledayi and latirostris not being sisters, the guidelines for coining new English names for both do not apply.

YES. Those English names seem fine and agree with other recent treatments.

YES. Those English names seem fine and agree with other recent treatments.

YES. I agree because I proposed those names. 

YES. These English names seem good and are in agreement with other checklists. 

YES. English names provided in proposal seem like good choices.

YES. The suggested English names seem appropriate. 

YES. I agree with the English names selected, but i wonder if we could consider Kimball Garrett’s motion to change members within Cynanthus to “Emeralds.” I realize there is a moratorium on English name changes, but this doesn’t reflect the eponymous names issue, rather better reflecting the taxonomic relationships. Since we are dealing with Cynanthus latirostris now, let’s consider Kimball’s motion this year too.


2022-A-21: Split Lampornis cinereicauda from White-throated Mountain-gem L. castaneoventris

NO. Little direct evidence (other than plumage) supporting a split is available. In addition, what genetic data that are available indicate gene flow among taxa examined.

NO. Reasons are outlined in the proposal. Further, much of the data are unpublished, which unofficially makes them unusable by our usual procedures. I see no reason to hurry here – let’s wait for all the published data and take another look. 

NO. I agree with the proposal that these are better treated as a single species for now. The lack of genetic differences, the fact that much of the data are unpublished, and the lack of information on potential contact and admixture all support the single-species treatment.

NO. I agree with the proposal that it is premature to split cinereicauda and castaneoventris. Until we better know what is happening near the regions of parapatry, reported in a peer reviewed paper, it is best to retain the status quo. 

NO. I recommend waiting for published data.

NO. Reasons are outlined in the proposal. I agree that it is premature to split these taxa, as the evidence is not very strong, and if anything, lumping them all together does seem to be the best option until detailed studies of hybridization can be conducted.

NO. At least for now.

NO. Reasons are stated in the proposal. A great group for someone to study, but we do not have enough evidence to split them currently.

NO. These do not look like good species, given current evidence (including the unpublished evidence provided here). I would also support lumping them as a polytypic species.

NO. The evidence is not yet there so better leave as is.

NO. A very interesting proposal and I did not know the situation was so complex with these Lampornis. Obviously the subject should be further pursued if there are regions where there is sympatry.