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Curve-billed Scythebill (1 Viewer)

Richard Klim

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Have you tried PDF requests?
No, because I'm one of those fortunate enough to have HBW. The Lynx website doesn't give author contact information and so doesn't help non-purchasers to make pdf requests, but of course that will only be a minor inconvenience for anyone genuinely interested.

And to be fair, several of the papers are already available online (eg, ResearchGate), and I recall that Lynx stated somewhere that the papers will be posted on their website at some time...
 
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thomasdonegan

Former amateur ornithologist
Do you want one rule for antbirds (and the beloved tapaculos) and another rule for woodcreepers Thomas?

No, one rule for all. Look at the Barred Woodcreepers and some of the Scythebill splits, and you will see a combination of miniscule molecular differentiation, no sympatry, vocal differences that seem like splitting of hairs and at most minor differences in plumage shade, pointing to subspecies rank being appropriate..

Look at some of the other Scythebill splits and those in Lepidocolaptes, and you will see significant molecular differentiation, major vocal differences and some plumage differences pointing to species rank being appropriate.

I call only for consistency between treatments for birds generally, irrespective of the authors of relevant publications.
 

ZanderII

Well-known member
No, one rule for all. Look at the Barred Woodcreepers and some of the Scythebill splits, and you will see a combination of miniscule molecular differentiation, no sympatry, vocal differences that seem like splitting of hairs and at most minor differences in plumage shade, pointing to subspecies rank being appropriate..

Look at some of the other Scythebill splits and those in Lepidocolaptes, and you will see significant molecular differentiation, major vocal differences and some plumage differences pointing to species rank being appropriate.

I call only for consistency between treatments for birds generally, irrespective of the authors of relevant publications.

None of these things are sympatric, you had picked on Lepidocolaptes early as an example of a group that didn't warrant upgrading to species status - are you happy that this split is ok now? Maybe cardosoi could be lumped with probatus, but as you say several other taxa in that group are as good splits as any that SACC have adopted recently.

I quite like those Dendrocolaptes certhia splits, Lewington made them look good (attached).
 

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lewis20126

Well-known member
None of these things are sympatric

Correct me if I'm wrong (my comments are almost always from memory not by recent reference!) but I thought the many of the newly claimed interfluvial "species" in HBW were very poorly known in the headwaters? Is allopatry / parapatry proven or assumed in these areas?

cheers, a
 

lewis20126

Well-known member
None of these things are sympatric

For example, from the description of Lepidocolaptes fatimalimae (Rodrigues et al. 2012, HBW, Special Volume, p251):

"We documented a single specimen with the plumage characters and NADH subunit 2 sequences of L. fatimalimae (LSUMZ 137058) within the range of L.a. fuscicapillus in eastern Santa Cruz, Bolivia (Fig 2); whether this instance of sympatry is accompanied by introgression between these taxa remains a subject for further research."

There are remarkably few specimens in this study from the southern fringes of the Amazon basin and headwaters of these rivers compared to the easily accessible banks of the lower reaches (the same pattern - or lack of one- is shown for the Dendrocolaptes certhia group)

cheers, alan
 

lewis20126

Well-known member
There are remarkably few specimens in this study from the southern fringes of the Amazon basin and headwaters of these rivers compared to the easily accessible banks of the lower reaches (the same pattern - or lack of one- is shown for the Dendrocolaptes certhia group)

cheers, alan

And also the last para (no pun intended) on vocalizations for Tolmomyias sucunduri, HBW special volumes, (p299) states: "South of approximately o5deg 40' south, however, this distinctive vocalization loses its identity, apparently due to hybridization...". To me this suggests that the forms lose their identities in the headwaters, as perhaps might be expected - interesting of course in any event!

cheers, a
 

ZanderII

Well-known member
Correct me if I'm wrong (my comments are almost always from memory not by recent reference!) but I thought the many of the newly claimed interfluvial "species" in HBW were very poorly known in the headwaters? Is allopatry / parapatry proven or assumed in these areas?

cheers, a

Very true, I mean most taxa have allopatric distruibutions, with some element of doubt exactly where ranges end (in many cases the rivers are still sizeable into transitional areas which are non habitat for several taxa). Headwaters are not as well sampled as the lower reaches of major rivers, although these are now being targeted by collecting trips. However plenty of areas have been targeted and although there is now evidence for contact zones between some taxa e.g. Rhegmatorhina berlepschi/hoffmannsi these are not assumed to be the norm. Moreover a narrow, stable hybrid zone is now not considered to be a barrier to calling something a species, e.g. Ficedulas, crows etc.
 
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ZanderII

Well-known member
For example, from the description of Lepidocolaptes fatimalimae (Rodrigues et al. 2012, HBW, Special Volume, p251):

"We documented a single specimen with the plumage characters and NADH subunit 2 sequences of L. fatimalimae (LSUMZ 137058) within the range of L.a. fuscicapillus in eastern Santa Cruz, Bolivia (Fig 2); whether this instance of sympatry is accompanied by introgression between these taxa remains a subject for further research."

There are remarkably few specimens in this study from the southern fringes of the Amazon basin and headwaters of these rivers compared to the easily accessible banks of the lower reaches (the same pattern - or lack of one- is shown for the Dendrocolaptes certhia group)

cheers, alan

If they are occurring in sympatry then great, BSC all the way... Agree that more collecting is necessarily, and it will have to be quick as most of the forest and the birds are disappearing in SE Amazonia.
 

ZanderII

Well-known member
And also the last para (no pun intended) on vocalizations for Tolmomyias sucunduri, HBW special volumes, (p299) states: "South of approximately o5deg 40' south, however, this distinctive vocalization loses its identity, apparently due to hybridization...". To me this suggests that the forms lose their identities in the headwaters, as perhaps might be expected - interesting of course in any event!

cheers, a

I have not seen but have listened to recordings of that bird and the call is very different from the rest of the assimilis group, as alluded to its the first author's contention that many taxa are likely being swamped by recent introgression in the Madeira mini-interfluves and may be in the process of 'de-speciating' so maybe a tough call on 'species'.

That said, the rest of the assimilis group is split-tastic, they all sound extremely different and most look different too. Molecular work and paper in the pipeline.

Compare:
examinatus: http://www.xeno-canto.org/168673
paraensis: http://www.xeno-canto.org/84125 & http://www.xeno-canto.org/9520
nominate: http://www.xeno-canto.org/species/Tolmomyias-assimilis?pg=2
obscuriceps: http://www.xeno-canto.org/11974
 

lewis20126

Well-known member
I have not seen but have listened to recordings of that bird and the call is very different from the rest of the assimilis group, as alluded to its the first author's contention that many taxa are likely being swamped by recent introgression in the Madeira mini-interfluves and may be in the process of 'de-speciating' so maybe a tough call on 'species'.

That said, the rest of the assimilis group is split-tastic, they all sound extremely different and most look different too. Molecular work and paper in the pipeline.

Compare:
examinatus: http://www.xeno-canto.org/168673
paraensis: http://www.xeno-canto.org/84125 & http://www.xeno-canto.org/9520
nominate: http://www.xeno-canto.org/species/Tolmomyias-assimilis?pg=2
obscuriceps: http://www.xeno-canto.org/11974

I'm only familiar with what I assume was examinatus (a number of years ago!) and obscuriceps (various localities, FWIW birds at Mitu this winter sound like this, I think I have a recording). PAJM and I were amazed at the song of "examinatus" (what does neglectus sound like?) when hearing this for the first time on the Rio Caura in Venezuala. I agree that the songs of these two forms, are indicative of specific status.

I'm struggling to hear anything on the paraensis cuts that might be a song! Indeed, the first cut seems to be dominated by a trogon species (Violaceous group? not checked), not listed on the background species. I'll have to have another listen when I have more time.

So I guess you've got a well-defined Guianan Shield bird, a West Amazonian species between the Rio Negro and the Maranon, and a group of forms south of the "Amazon" and you'll know these far better than me! I think the problem will be convincing SACC, that there is enough evidence for the specific status of the southern forms, espeically in the context of BW's statement, quoted above. If anyone is drafting a new SACC proposal, perhaps a conservative first step would be to go for 3!!

cheers, a
 

ZanderII

Well-known member
I'm struggling to hear anything on the paraensis cuts that might be a song! Indeed, the first cut seems to be dominated by a trogon species (Violaceous group? not checked), not listed on the background species. I'll have to have another listen when I have more time.

http://www.xeno-canto.org/84125 the tick notes throughout are the dawn song, the other cut is the call/song that is uttered throughout the day.

Two taxa occur in the same mini-interfluve - Juruena-Teles Pires south of Alta Floresta, turning over along an edaphic gradient. The songs/calls are not at all similar:

http://www.birdingmatogrosso.com/PDFS/Serra dos Caiabis - Cotinga.pdf
 

lewis20126

Well-known member
http://www.xeno-canto.org/84125 the tick notes throughout are the dawn song, the other cut is the call/song that is uttered throughout the day.

Two taxa occur in the same mini-interfluve - Juruena-Teles Pires south of Alta Floresta, turning over along an edaphic gradient. The songs/calls are not at all similar:

http://www.birdingmatogrosso.com/PDFS/Serra dos Caiabis - Cotinga.pdf

Thanks, I'll have to have another listen later ánd try and see if I can work out what is going on.

When you mentioned de-speciation earlier in relation to the southern range of sucunduri, I guess you suggesting that this is a secondary contact? I'm not too familiar with the historic expansion / contraction of the Amazonian Forest and how this relates to the rivers to understand whether this is the mechanism for the initial divergence.

cheers, a
 

ZanderII

Well-known member
Thanks, I'll have to have another listen later ánd try and see if I can work out what is going on.

When you mentioned de-speciation earlier in relation to the southern range of sucunduri, I guess you suggesting that this is a secondary contact? I'm not too familiar with the historic expansion / contraction of the Amazonian Forest and how this relates to the rivers to understand whether this is the mechanism for the initial divergence.

cheers, a

Yes, secondary contact (not necessarily with closest relatives), because of drainage capture and changes in the course of the Tapajos and tributaries. Have a read of http://antonelli-lab.net/pdf/Fernandes_2013_BiodiversConserv.pdf to get the gist of what all this means for biodiversity conservation:
 

thomasdonegan

Former amateur ornithologist
None of these things are sympatric, you had picked on Lepidocolaptes early as an example of a group that didn't warrant upgrading to species status - are you happy that this split is ok now? Maybe cardosoi could be lumped with probatus, but as you say several other taxa in that group are as good splits as any that SACC have adopted recently.

Our Colombian checklist team's approaches on these taxa are here:

http://www.proaves.org/wp-content/u...date-2013-Conservacion-Colombiana-19-3-10.pdf
 

ZanderII

Well-known member
Our Colombian checklist team's approaches on these taxa are here:

http://www.proaves.org/wp-content/u...date-2013-Conservacion-Colombiana-19-3-10.pdf

Fair comments, I had read them already. My issue is the attempt to apply Isler et al. criteria to cryptic furnarids when we consider several large woodcreeper taxa to be good species despite no vocal differentiation. Songs in this group just don't appear to be very divergent among superspecies complexes. Sooner or later there will be a lot more woodcreeper proposals, check out the attached image: Dendrocincla merula either side of the Tocantins.
 

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lewis20126

Well-known member
http://www.xeno-canto.org/84125 the tick notes throughout are the dawn song, the other cut is the call/song that is uttered throughout the day.

Two taxa occur in the same mini-interfluve - Juruena-Teles Pires south of Alta Floresta, turning over along an edaphic gradient. The songs/calls are not at all similar:

http://www.birdingmatogrosso.com/PDFS/Serra dos Caiabis - Cotinga.pdf

The first cut of "paraensis" is certainly very unusual for a Tolmomyias - I was reminded of something and have just remembered the "song" of Todirostrum pictum, which is not dissimilar (though the notes are delivered at a faster pace). The second song is also unusual and sounds a little like a Myiarchus!

I think in the Cotinga article, it is suggested that the nominate form (or a bird with identical song) is also present, so assume this is the second taxa. I would guess the edaphic gradient is not a simple line so might these birds be locally sympatric anyway? I think the same happens with a large non-passerine, with two song types on different soils, that someone is supposed to be working on..

cheers, alan
 

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