Turdidae (1 Viewer)

andyadcock said:

Do both occur in Costa Rica, descriptions of the range of each species suggest that they do so like many people, I will now have to try and resolve the ID of birds I saw there?

Click to expand...

According to Cornell Lab of Ornithology’s “All About Birds” website, “Russet-backed Thrush” winters in Central America and Swainson’s Thrush winters in South America. I would assume that Swainson’s Thrushes migrate through Central America on their way to South America.

Dave

Nightjar61 said:

According to Cornell Lab of Ornithology’s “All About Birds” website, “Russet-backed Thrush” winters in Central America and Swainson’s Thrush winters in South America. I would assume that Swainson’s Thrushes migrate through Central America on their way to South America.

Dave

Click to expand...

Thanks Dave, so the answer is probably yes, they both occur in CR.

Both forms are defined as ebird groups. Here are the maps:
https://ebird.org/map/swathr1?neg=t...mr=1-12&bmo=1&emo=12&yr=all&byr=1900&eyr=2019
https://ebird.org/map/swathr2?neg=t...mr=1-12&bmo=1&emo=12&yr=all&byr=1900&eyr=2019

You might be able to get more details by looking at occurrence in different months of the year, limitations to recent years, etc.

Niels

Thanks Niels, so now I and others, are stuck with Catharus sp on the list where it used to say Swainson's Thrush as both, will be migrants? Grrrrr

andyadcock said:

Thanks Niels, so now I and others, are stuck with Catharus sp on the list where it used to say Swainson's Thrush as both, will be migrants? Grrrrr

Click to expand...

I believe I have a couple of photos which eventually needs to be looked at in more detail ...

Niels

andyadcock said:

Thanks Niels, so now I and others, are stuck with Catharus sp on the list where it used to say Swainson's Thrush as both, will be migrants? Grrrrr

Click to expand...

Maybe not. It depends when you were in Costa Rica. I’d assume that any birds seen in mid-winter would be “Russet-backed” as at that time all Swainson’s should be in South America. On the other hand, if you were there in late fall-early winter or late winter-early spring then both would presumably be present.

Dave

If you take the above maps and only show December, both forms are seen in CR during that month. Whether those determinations are correctly identified observations is unknown to me.

Niels

njlarsen said:

If you take the above maps and only show December, both forms are seen in CR during that month. Whether those determinations are correctly identified observations is unknown to me.

Niels

Click to expand...

Thanks again Niels and David.
I saw good numbers in one particular place where they were all feeding on a fruiting tree, 3rd April at La Esquinas.

My best effort is attached and it looks fairly cold on what little can be seen of the back, but not certain this is enough?

Catharus bicknelli, C. minimus

Alyssa M Fitzgerald, Jason Weir, Joel Ralston, Ian G Warkentin, Darroch M Whitaker, Jeremy J Kirchman, Genetic structure and biogeographic history of the Bicknell’s Thrush/ Gray-cheeked Thrush species complex, The Auk, , ukz066, https://doi.org/10.1093/auk/ukz066

Abstract:

We examined species limits, admixture, and genetic structure among populations in the Bicknell’s Thrush (Catharus bicknelli)–Gray-cheeked Thrush (C. minimus) species complex to establish the geographic and temporal context of speciation in this group, which is a model system in ecology and a high conservation priority. We obtained mitochondrial ND2 sequences from 186 Bicknell’s Thrushes, 77 Gray-cheeked Thrushes, and 55 individuals of their closest relative, the Veery (C. fuscescens), and genotyped a subset of individuals (n = 72) at 5,633 anonymous single nucleotide polymorphic (SNP) loci. Between-species sequence divergence was an order of magnitude greater than divergence within each species, divergence was dated to the late Pleistocene (420 kbp) based on Bayesian coalescence estimation, and a coalescent model (IMa) revealed almost no gene flow between species based on ND2. SNP data were consistent with mitochondrial results and revealed low levels of admixture among species (3 of 37 Bicknell’s Thrushes, no Gray-cheeked Thrushes, and no Veeries were >2% admixed). Species distribution models projected to the Last Glacial Maximum suggest that Bicknell’s Thrush and Gray-cheeked Thrush resided in primarily allopatric refugia in the late Pleistocene, consistent with the genetic data that support reproductive isolation over an extended period of time. Our genetic data suggest that both species underwent demographic expansions, possibly as they expanded out of Pleistocene refugia into their current ranges. We conclude that Bicknell’s Thrush and Gray-cheeked Thrush are 2 distinct species-level lineages despite low levels of Gray-cheeked Thrush introgression in Bicknell’s Thrushes, and divergence has been maintained by a long history of allopatry in subtly different habitats. Their unique phylogeography among boreal forest birds indicates that either cryptic species breaks in eastern North America are still undiscovered, or another factor, such as divergent natural selection, high migratory connectivity, or interspecific competition, played a role in their divergence.

Romina Batista, Urban Olsson, Tobias Andermann, Alexandre Aleixo, Camila Cherem Ribas and Alexandre Antonelli, 2020

Phylogenomics and biogeography of the world's thrushes (Aves, Turdus): new evidence for a more parsimonious evolutionary history.

Proceedings of the Royal Society B 287(1919): 20192400
doi: https://doi.org/10.1098/rspb.2019.2400
https://royalsocietypublishing.org/doi/10.1098/rspb.2019.2400

Abstract

To elucidate the relationships and spatial range evolution across the world of the bird genus Turdus (Aves), we produced a large genomic dataset comprising ca 2 million nucleotides for ca 100 samples representing 53 species, including over 2000 loci. We estimated time-calibrated maximum-likelihood and multispecies coalescent phylogenies and carried out biogeographic analyses. Our results indicate that there have been considerably fewer trans-oceanic dispersals within the genus Turdus than previously suggested, such that the Palaearctic clade did not originate in America and the African clade was not involved in the colonization of the Americas. Instead, our findings suggest that dispersal from the Western Palaearctic via the Antilles to the Neotropics might have occurred in a single event, giving rise to the rich Neotropical diversity of Turdus observed today, with no reverse dispersals to the Palaearctic or Africa. Our large multilocus dataset, combined with dense species-level sampling and analysed under probabilistic methods, brings important insights into historical biogeography and systematics, even in a scenario of fast and spatially complex diversification.

Enjoy,

Fred

Fred Ruhe said:

Romina Batista, Urban Olsson, Tobias Andermann, Alexandre Aleixo, Camila Cherem Ribas and Alexandre Antonelli, 2020

Phylogenomics and biogeography of the world's thrushes (Aves, Turdus): new evidence for a more parsimonious evolutionary history.

Proceedings of the Royal Society B 287(1919): 20192400
doi: https://doi.org/10.1098/rspb.2019.2400
https://royalsocietypublishing.org/doi/10.1098/rspb.2019.2400

Click to expand...

Interesting one. I see it retains T. viscivorus as close to basal in the genus (making splitting the genus a nightmare as it is the type species so Turdus s.str. could only contain that species alone!). But the earlier suggestion that T. iliacus was sister to T. migratorius has gone (I was very suspicious of that one!). What's sad though is that most of the Asian thrushes are omitted, their sampling in this region is very weak, which makes the results for the included European and few Asian thrushes very uncertain.

Nutcracker said:

Interesting one. I see it retains T. viscivorus as close to basal in the genus (making splitting the genus a nightmare as it is the type species so Turdus s.str. could only contain that species alone!).

Click to expand...

Yes if you take the type fixation from: Gray GR. 1840. A list of the genera of birds, with an indication of the typical species of each genus. R and JE Taylor, London.; p. 27; https://biodiversitylibrary.org/page/13668921 -- as is done conventionally.

Fifteen years earlier, Prideaux John Selby (Selby PJ. 1825. Illustrations of British ornithology. Vol. I. Land birds. WH Lizard, Edinburg.; p. xxix & xxxii; https://biodiversitylibrary.org/page/38626829 & https://biodiversitylibrary.org/page/38626796 ) designated Turdus merula. Selby's designations are admittedly a bit unconventional (he listed species under a title 'Types of the genera' at the start of his book, using only vernacular names and associating them with a generic name; then he associated a scientific name to these vernaculars lower down in his text). Yet, Coracias and Alauda are on the Official List with similar type fixations accepted from this work.

l_raty said:

Yes if you take the type fixation from: Gray GR. 1840. A list of the genera of birds, with an indication of the typical species of each genus. R and JE Taylor, London.; p. 27; https://biodiversitylibrary.org/page/13668921 -- as is done conventionally.

Fifteen years earlier, Selby (Selby PJ. 1825. Illustrations of British ornithology. Vol. I. Land birds. WH Lizard, Edinburg.; p. xxix & xxxii; https://biodiversitylibrary.org/page/38626829 & https://biodiversitylibrary.org/page/38626796 ) designated Turdus merula. Selby's designation are admittedly a bit unconventional (he listed species under a title 'Types of the genera' at the start of his book, using only vernacular names and associating them with a generic name; then he associated a scientific name to these vernaculars lower down in his text). Yet, Coracias and Alauda are on the Official List with similar type fixations accepted from this work.

Click to expand...

And also Whitethroat ('Greater Pettychaps'), rather than conventional Blackcap, for Sylvia - can't see these getting accepted now as it would upset existing nomenclature too much? What about his Alcedo ispida for Kingfisher, though? That makes much better sense for the type of Alcedo, rather than what was originally Gracula atthis currently used?

Nutcracker said:

And also Whitethroat ('Greater Pettychaps'), rather than conventional Blackcap, for Sylvia - can't see these getting accepted now as it would upset existing nomenclature too much? What about his Alcedo ispida for Kingfisher, though? That makes much better sense for the type of Alcedo, rather than what was originally Gracula atthis currently used?

Click to expand...

I am not sure I follow you here. How would reverting to an older type species be upsetting as long as both are members of the genus as currently defined? It would become upsetting at the moment that a split moved the two apart but not before.

Niels

Nutcracker said:

And also Whitethroat ('Greater Pettychaps'), rather than conventional Blackcap, for Sylvia - can't see these getting accepted now as it would upset existing nomenclature too much? What about his Alcedo ispida for Kingfisher, though? That makes much better sense for the type of Alcedo, rather than what was originally Gracula atthis currently used?

Click to expand...

Sylvia is no problem -- the species designated by Selby was not one of the species included by Scopoli (Sylvia luscinia, S. curruca, S. atricapilla, S. oenanthe, S. rubecula, S. phoenicurus, S. tithys, S. zya, S. muscipeta, S. rubetra, S. trochilus, S. troglodytes, S. regulus), hence his designation cannot stand. The type was fixed by Bonaparte in 1828.
The type of Alcedo is A. ispida. (By designation in: Swainson W. 1820-21. Zoological illustrations, or, original figures and descriptions of new, rare, or interesting animals, selected chiefly from the classes of ornithology, entomology, and conchology, and arranged on the principles of Cuvier and other modern zoologists. Vol. I. Printed by R. and A. Taylor for Baldwin, Cradock, and Joy; and W. Wood, Strand, London.; text to pl.26; https://biodiversitylibrary.org/page/29156534 -- still earlier than Selby 1825. Gracula atthis [as the name implies] was not included in Alcedo by Linnaeus, and is in no way eligible to be the type of the genus.)
The type designated by Selby for Otis is a bit more problematic, though.

Note that the only way to discard an overlooked type designation allowed by the Code is to submit a case to the Commission.

l_raty said:

The type of Alcedo is A. ispida. (By designation in: Swainson W. 1820-21. Zoological illustrations, or, original figures and descriptions of new, rare, or interesting animals, selected chiefly from the classes of ornithology, entomology, and conchology, and arranged on the principles of Cuvier and other modern zoologists. Vol. I. Printed by R. and A. Taylor for Baldwin, Cradock, and Joy; and W. Wood, Strand, London.; text to pl.26; https://biodiversitylibrary.org/page/29156534 -- still earlier than Selby 1825. Gracula atthis [as the name implies] was not included in Alcedo by Linnaeus, and is in no way eligible to be the type of the genus.)
The type designated by Selby for Otis is a bit more problematic, though.

Click to expand...

So how come Alcedo ispida is just a subspecies of Gracula atthis a taxon first described in a different genus? Shouldn't it be the other way round? Both the same date, of course.
(sort of feeling I've asked this before, but can't remember the answer!)

njlarsen said:

It would become upsetting at the moment that a split moved the two apart but not before.

Click to expand...

Sylvia is restricted to atricapilla, borin, dohrni and abyssinica in H&M4 (whitethroats are in Curruca).

Nutcracker said:

So how come Alcedo ispida is just a subspecies of Gracula atthis a taxon first described in a different genus? Shouldn't it be the other way round? Both the same date, of course.
(sort of feeling I've asked this before, but can't remember the answer!)

Click to expand...

They both date from Linnaeus 1758, thus a first reviser action is needed. I think the FR was Temminck 1815 https://archive.org/stream/manueldornithol00natugoog#page/n306/mode/2up , who used Alcedo ispida as valid and listed Gracula athis [sic] in its synonymy (albeit he attributed both names to Gmelin), which gives precedence to ispida. Initially, A. ispida was used more or less universally for the species, until Laubmann 1916 http://biodiversitylibrary.org/page/32643189 argued that atthis has page priority; this was subsequently followed by Hartert, and finally gained universal acceptance.

But if you follow the ICZN, it should be the other way around, indeed.

l_raty said:

They both date from Linnaeus 1758, thus a first reviser action is needed. I think the FR was Temminck 1815 https://archive.org/stream/manueldornithol00natugoog#page/n306/mode/2up , who used Alcedo ispida as valid and listed Gracula athis [sic] in its synonymy (albeit he attributed both names to Gmelin), which gives precedence to ispida. Initially, A. ispida was used more or less universally for the species, until Laubmann 1916 http://biodiversitylibrary.org/page/32643189 argued that atthis has page priority; this was subsequently followed by Hartert, and finally gained universal acceptance.

But if you follow the ICZN, it should be the other way around, indeed.

Click to expand...

Thanks! Time that someone said so officially? Get IOC and others to take up Temminck's position?

TiF Update February 29

I'm celebrating Leap Day by updating the list. I was unhappy with the previous treatment of Turdus, and a couple of new papers have helped matters.

It's still the case that I don't have the time necessary to do regular updates, so it will probably be a while before the next one.

Thrushes: There have been several taxonomic changes, as well as a general rearrangement of Turdus using Batista et al. (2020) and Nagy et al. (2019), as well as some adjustments to Catharus based on Everson et al. (2019).

The Groundscraper Thrush, Turdus litsitsirupa, has been returned to genus Psophocichla.
Ethiopian Thrush, Psophocichla simensis, has been split from from Groundscraper Thrush, Psophocichla litsitsirupa, based on Nylander et al. (2008) and the HBW Checklist.
The Chinese Thrush, Turdus mupinensis, has been moved to the monotypic genus Otochichla based on Nylander et al. (2008), Nagy et al. (2019), and the HBW Checklist.
Split Dagua Thrush, Turdus daguae, from White-throated Thrush, Turdus assimilis (Ridgely and Greenfield, 2001; IOC).
[Turdidae, Muscicapoidea II, 3.14]