-
Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.
Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
Turdidae (4 Viewers)
- Thread starter Peter Kovalik
- Start date
Jim LeNomenclatoriste
Je suis un mignon petit Traquet rubicole
albertonykus
Well-known member
Kirwan, G.M. and N.J. Collar (2023)
Comments on the taxonomic status and disappearance of Mimocichla rubripes eremita Ridgway, 1905, with a substitute name, and notes on the type material of M. coryi Sharpe, 1902
Bulletin of the British Ornithologists’ Club 143: 362–369
doi: 10.25226/bboc.v143i3.2023.a12
A population of the West Indian endemic Red-legged Thrush Turdus plumbeus formerly inhabited the Swan Islands (off northern Honduras), but is apparently extinct, having first and last been seen in 1887. Named Mimocichla rubripes eremita Ridgway, 1905, it fell into the synonymy of T. p. rubripes, found across the western two-thirds of Cuba. A recent check on seven Swan Islands specimens suggests that the validity of their subspecific status might be upheld for their apparently more extensive black throat, but further study is needed. The extinction of the population cannot be explained, but economic activity in the years from the 1850s to 1900s conceivably played a part. Meanwhile, Tristan Thrush Nesocichla eremita Gould, 1855, endemic to the archipelago of Tristan da Cunha, is nowadays also reassigned to Turdus. To resolve the resultant case of secondary homonymy, a substitute name for the Swan Islands population of Turdus plumbeus is offered.
Comments on the taxonomic status and disappearance of Mimocichla rubripes eremita Ridgway, 1905, with a substitute name, and notes on the type material of M. coryi Sharpe, 1902
Bulletin of the British Ornithologists’ Club 143: 362–369
doi: 10.25226/bboc.v143i3.2023.a12
A population of the West Indian endemic Red-legged Thrush Turdus plumbeus formerly inhabited the Swan Islands (off northern Honduras), but is apparently extinct, having first and last been seen in 1887. Named Mimocichla rubripes eremita Ridgway, 1905, it fell into the synonymy of T. p. rubripes, found across the western two-thirds of Cuba. A recent check on seven Swan Islands specimens suggests that the validity of their subspecific status might be upheld for their apparently more extensive black throat, but further study is needed. The extinction of the population cannot be explained, but economic activity in the years from the 1850s to 1900s conceivably played a part. Meanwhile, Tristan Thrush Nesocichla eremita Gould, 1855, endemic to the archipelago of Tristan da Cunha, is nowadays also reassigned to Turdus. To resolve the resultant case of secondary homonymy, a substitute name for the Swan Islands population of Turdus plumbeus is offered.
pbjosh
missing the neotropics
Looping back to the Catharus fuscator paper, I’ve finally had a first look at it. Here’s a summary of the proposed 7 splits:
On first sniff, the result they present that the Talamanca clade is sister to all remaining birds makes sense. That the two Darien clades are sisters and then in turn the clade of those two are sister to all S American clades makes sense. The further radiation south of the thrushes resulting in fewer species further south in the Andes also sort of follows existing biogeographic patterns and is not surprising. Perhaps a bit surprising that they find so much differentiation between birds on Pirre and Talamanca but not as much differentiation in Santa Marta birds… this is a less common / expected biogeographic result, perhaps.
I have quite a bit of field experience with several of the forms but not all. I’m not sure I personally see the differences between all the taxa as being as large as the authors do, though I can easily believe that there are multiple species there. I do not recall vocal differences being remarkable particularly in a group like Thrushes, but it makes me want to read into their sonogram analyses more and listen to the samples they used but not sure when I’ll get time for that. In my experience if you know what C fuscater (senso lato) sounds like anywhere you’ll probably recognize the other subspps pretty readily as belonging to the same group.
I’m curious what others think of this, either on the genetics side or on the vocalizations side or just general chit chat about it. Catharus thrushes are super cool and I won’t be upset to keep looking for more forms of this species in the future.
- Talamanca NT C hellmayri - Costa Rica and W Panama
- Darien NT C arcanus - highlands of the Darien except for Pirre
- Pirre NT C mirabilis - Cerro Pirre
- Cordilleran NT C fuscater - Venezuela, Perija, Santa Marta, E Andes of Colombia
- Trans-Andean NT C berlepschi - W Andes of Ecuador and N Peru, E slope Peru S to Cusco (Rio Apurimac)
- Antioquia NT C opertaneus - W and C Andes of Colombia, E slope of N Ecuador
- Cochabamba NT C mentalis - S Peru E of Apurimac to Santa Cruz, Bolivia
On first sniff, the result they present that the Talamanca clade is sister to all remaining birds makes sense. That the two Darien clades are sisters and then in turn the clade of those two are sister to all S American clades makes sense. The further radiation south of the thrushes resulting in fewer species further south in the Andes also sort of follows existing biogeographic patterns and is not surprising. Perhaps a bit surprising that they find so much differentiation between birds on Pirre and Talamanca but not as much differentiation in Santa Marta birds… this is a less common / expected biogeographic result, perhaps.
I have quite a bit of field experience with several of the forms but not all. I’m not sure I personally see the differences between all the taxa as being as large as the authors do, though I can easily believe that there are multiple species there. I do not recall vocal differences being remarkable particularly in a group like Thrushes, but it makes me want to read into their sonogram analyses more and listen to the samples they used but not sure when I’ll get time for that. In my experience if you know what C fuscater (senso lato) sounds like anywhere you’ll probably recognize the other subspps pretty readily as belonging to the same group.
I’m curious what others think of this, either on the genetics side or on the vocalizations side or just general chit chat about it. Catharus thrushes are super cool and I won’t be upset to keep looking for more forms of this species in the future.
l_raty
laurent raty
I know I'm a bit of a pain, but is there evidence of a ZooBank registration in the paper ?
pbjosh
missing the neotropics
No clue. I am traveling and had some very welcome down time yesterday so took a quick look through it. It’s quite long so there was a fair bit of the vocal analyses and description details I glazed over. Happy to email you the paper if you like, pm me, or you can easily request it from the lead author via his website.
Yes, there are Zoobank codes under each newly named taxon.
Catharus arcanus sp. nov.: urn:lsid:zoobank.org:act:25B3DB71-FE5E-4FBF-A2CE-8D270CBA7250
Catharus berlepschi nebulus ssp. nov.: urn:lsid:zoobank.org:act:EAE392CC-A763-4E5E-8F6F-68921515C9A2
Catharus opertaneus tenebris ssp. nov.: urn:lsid:zoobank.org:act:B1F7F134-2EB8-4FB9-A1EB-31E2CC7AB4D7
Peter Kovalik
Well-known member
Abigail A. Kimmitt, Teresa M. Pegan, Andrew W. Jones, Kevin Winker, and Benjamin M. Winger (2023) How Veeries vary: Whole genome sequencing resolves genetic structure in a long-distance migratory bird. Ornithology, ukad061.
How Veeries vary: Whole genome sequencing resolves genetic structure in a long-distance migratory bird
Abstract
In high-latitude species with high dispersal ability, such as long-distance migratory birds, populations are often assumed to exhibit little genetic structure due to high gene flow or recent postglacial expansion. We sequenced over 120 low-coverage whole genomes from across the breeding range of a long-distance migratory bird, the Veery (Catharus fuscescens), revealing strong evidence for isolation by distance. Additionally, we found distinct genetic structure between boreal, western montane U.S., and southern Appalachian sampling regions. We suggest that population genetic structure in this highly migratory species is detectable with the high resolution afforded by whole-genomic data because, similar to many migratory birds, the Veery exhibits high breeding-site fidelity, which likely limits gene flow. Resolution of isolation by distance across the breeding range was sufficient to assign likely breeding origins of individuals sampled in this species’ poorly understood South American nonbreeding range, demonstrating the potential to assess migratory connectivity in this species using genomic data. As the Veery’s breeding range extends across both historically glaciated and unglaciated regions in North America, we also evaluated whether contemporary patterns of structure and genetic diversity are consistent with historical population isolation in glacial refugia. We found that patterns of genetic diversity did not support southern montane regions (southern Appalachians or western U.S. mountains) as glacial refugia. Overall, our findings suggest that isolation by distance yields subtle associations between genetic structure and geography across the breeding range of this highly vagile species even in the absence of obvious historical vicariance or contemporary barriers to dispersal.
How Veeries vary: Whole genome sequencing resolves genetic structure in a long-distance migratory bird
Abstract
In high-latitude species with high dispersal ability, such as long-distance migratory birds, populations are often assumed to exhibit little genetic structure due to high gene flow or recent postglacial expansion. We sequenced over 120 low-coverage whole genomes from across the breeding range of a long-distance migratory bird, the Veery (Catharus fuscescens), revealing strong evidence for isolation by distance. Additionally, we found distinct genetic structure between boreal, western montane U.S., and southern Appalachian sampling regions. We suggest that population genetic structure in this highly migratory species is detectable with the high resolution afforded by whole-genomic data because, similar to many migratory birds, the Veery exhibits high breeding-site fidelity, which likely limits gene flow. Resolution of isolation by distance across the breeding range was sufficient to assign likely breeding origins of individuals sampled in this species’ poorly understood South American nonbreeding range, demonstrating the potential to assess migratory connectivity in this species using genomic data. As the Veery’s breeding range extends across both historically glaciated and unglaciated regions in North America, we also evaluated whether contemporary patterns of structure and genetic diversity are consistent with historical population isolation in glacial refugia. We found that patterns of genetic diversity did not support southern montane regions (southern Appalachians or western U.S. mountains) as glacial refugia. Overall, our findings suggest that isolation by distance yields subtle associations between genetic structure and geography across the breeding range of this highly vagile species even in the absence of obvious historical vicariance or contemporary barriers to dispersal.
albertonykus
Well-known member
Blain, S.A., H.C. Justen, W. Easton, and K.E. Delmore (2024)
Reduced hybrid survival in a migratory divide between songbirds
Ecology Letters 27: e14420
doi: 10.1111/ele.14420
Migratory divides, hybrid zones between populations that use different seasonal migration routes, are hypothesised to contribute to speciation. Specifically, relative to parental species, hybrids at divides are predicted to exhibit (1) intermediate migratory behaviour and (2) reduced fitness as a result. We provide the first direct test of the second prediction here with one of the largest existing avian tracking datasets, leveraging a divide between Swainson's thrushes where the first prediction is supported. Using detection rates as a proxy for survival, our results supported the migratory divide hypothesis with lower survival rates for hybrids than parental forms. This finding was juvenile-specific (vs. adults), suggesting selection against hybrids is stronger earlier in life. Reduced hybrid survival was not explained by selection against intermediate phenotypes or negative interactions among phenotypes. Additional work connecting specific features of migration is needed, but these patterns provide strong support for migration as an ecological driver of speciation.
Reduced hybrid survival in a migratory divide between songbirds
Ecology Letters 27: e14420
doi: 10.1111/ele.14420
Migratory divides, hybrid zones between populations that use different seasonal migration routes, are hypothesised to contribute to speciation. Specifically, relative to parental species, hybrids at divides are predicted to exhibit (1) intermediate migratory behaviour and (2) reduced fitness as a result. We provide the first direct test of the second prediction here with one of the largest existing avian tracking datasets, leveraging a divide between Swainson's thrushes where the first prediction is supported. Using detection rates as a proxy for survival, our results supported the migratory divide hypothesis with lower survival rates for hybrids than parental forms. This finding was juvenile-specific (vs. adults), suggesting selection against hybrids is stronger earlier in life. Reduced hybrid survival was not explained by selection against intermediate phenotypes or negative interactions among phenotypes. Additional work connecting specific features of migration is needed, but these patterns provide strong support for migration as an ecological driver of speciation.
Mysticete
Well-known member
IIRC, there was a failed proposal to split Swainson's Thrush a few years ago that the AOS voted on. I wonder if this paper would change there minds, or if selection against hybrids due to migration patterns mismatch is not considered a "valid mechanism" to enforce speciation.
Mysticete
Well-known member
For those curious about the votes of the proposal in question:
americanornithology.org
Comments 2021-C - American Ornithological Society
2021-C-1: Revise the classification of the Antillean Piculet Nesoctites micromegas 2021-C-2: Transfer Flammulated Flycatcher Deltarhynchus flammulatus to Ramphotrigon 2021-C-3: Treat Cistothorus stellaris as a separate species from C. platensis 2021-C-4: Elevate Turdus rufopalliatus graysoni to...
americanornithology.org
Mysticete
Well-known member
Another Swainson's Thrush paper just came out.
Mapping seasonal migration in a songbird hybrid zone -- heritability, genetic correlations, and genomic patterns linked to speciation
https://www.pnas.org/doi/10.1073/pnas.2313442121Similar threads
