Proposal 378 to the South American Classification Committee was accepted and SACC now recognizes Trogon caligatus as a separate species from Trogon violaceus. The proposal is based on qualitative vocal data and on genetic analysis in the following paper:
DaCOSTA, J. M., AND J. KLICKA. 2008. The Great American Interchange in birds: a phylogenetic perspective with the genus Trogon. Molecular Ecology 17: 1328-1343.
Flickr images for trogon violaceus
In xeno-canto the subspecies caligatus and violaceous are not mentioned, and from the proposal itself it is not clear which subspecies belong with the caligatus group. Zimmer, in the discussion of the proposal says: 'the caligatus group of Central America and trans-Andean western South America'.
The Internet Bird collection has the following information on subspecies and distribution:
- sallaei (Bonaparte, 1856) - Caribbean slope of E & S Mexico, also Pacific slope of S Mexico, and Guatemala, Belize, El Salvador and N Honduras; possibly this race in Nicaragua.
- concinnus (Lawrence, 1862) - Costa Rica, Panama (except Caribbean slope of Darién), W Colombia, W Ecuador and NW Peru.
- caligatus (Gould, 1838) - NE Panama (Caribbean slope of Darién) into N Colombia and W Venezuela.
- violaceus (J. F. Gmelin, 1788) - E Venezuela, the Guianas and adjacent N Brazil; Trinidad.
- ramonianus (Deville & Des Murs, 1849) - Amazonian areas of Colombia, Ecuador, Peru, Bolivia and Brazil; also penetrates S Venezuela (upper R Orinoco).
- crissalis (Cabanis & Heine, 1863) - NE Brazil on S bank of lower R Amazon and tributaries (E of R Tapajós).
I am assuming that sallaei, caligatus and concinnus (all trans-Andean taxa) together constitute the caligatus group. This is further confirmed by a comment by Nores on the SACC site.
Let's see if we can name all subspecies on recordings in xeno-canto. At this moment (june 16 2009) there are 33 recordings, 13 foreground and 20 background. Interestingly, background recordings (which are not shown on the map below) are all that is present from large parts of Amazonia.
A map with recording localities for query trogon violaceus
In the following remarks on the vocalisation in italics are by Kevin Zimmer and taken from the comments on the SACC proposal. He starts off saying that
KZ: '....I would go further and strongly suggest that ramonianus, together with crissalis, constitutes a species distinct from both nominate violaceus and the caligatus group of Central America and trans-Andean western South America.
The DaCosta & Klicka paper presents genetic data backing such a treatment for ramonianus, which, in my experience, is the most vocally distinct taxon in the entire group. There is no published vocal analysis to prove this, but there are published qualitative descriptions, as well as published sample recordings of nominate violaceus, the caligatus group, and ramonianus/crissalis. Examples are also searchable online at the Macaulay Laboratory website (probably also at Xenocanto).'
Perhaps this can also be seen from the recordings here.
Trogon violaceus group
KZ: For example, go to the Macaulay Library site, and do a search for Trogon violaceus recordings. Check out LNS recordings #38963 (Ted Parker recording from Pando, Bolivia) and #11364 (Curtis Marantz recording from Amazonas, Brazil), both of which are representative of ramonianus. You will see that the notes of the song have a diphthongal or nearly bisyllabic quality. This squares with the description of the song of “Amazonian Violaceous Trogon” in Ridgely & Greenfield’s Birds of Ecuador, which the authors describe as “a fast but relatively short series of clipped “cow” notes, the notes often becoming doubled (“cadow-cadow-cadow..”).”
This description fits the sounds here rather well.
T.v.crissalis is probably heard in the background of XC17713.
KZ: Songs of crissalis, although possibly not identical to those of ramonianus, are at least distinctly similar, and are noticeably different from those of nominate violaceus.
KZ: Again, compare the two LNS recordings of ramonianus noted above to any LNS recordings of nominate violaceus from the Guianan region, or to any recordings of the caligatus group from Central America or western South America.
Trogon caligatus group
A map with recording localities for query trogon caligatus
XC10723 is probably T.c.caligatus.
KZ: This is in marked contrast to not only the songs of trans-Andean caligatus, but also to Guianan/n Amazonia east of the rio Negro nominate violaceus, both of which sound much more like Blue-crowned Trogon (T. curucui) in having a longer, faster series of higher-pitched notes which are more reminiscent of the song of Ferruginous Pygmy-Owl (Glaucidium brasilianum).
From this it is clear I think the quality of the notes in the caligatus group and violaceus is indeed rather different from ramonianus and crissalis. Kevin Zimmer remarks further:
KZ: In my experiences, the differences noted (bisyllabic or diphthongal notes, fewer notes per song, slower pace and lower pitch for ramonianus versus single-syllable notes, many more notes per song delivered at faster pace and higher pitch for nominate violaceus) are absolutely consistent throughout their respective ranges.
The data in xeno-canto may not be sufficient to check all these claims, I did not check them in any case. Perhaps they go a long way, but more recordings will be needed to clarify or quantify these points, which leaves the following remarks:
KZ: I would argue that the available genetic, morphological and vocal evidence for splitting ramonianus/crissalis from nominate violaceus is at least as solid as the evidence for splitting the caligatus group from nominate, and that the vocal differences are much greater between ramonianus/crissalis and nominate, than between nominate and the caligatus group.
for the future. Perhaps the xeno-canto community can help out by going through old tape and finding examples of songs from all over Amazonia. A final remark by Zimmer:
KZ: (Caution: Do not be misled by some of the purported violaceus LNS recordings from Mato Grosso, Brazil, which sound like north bank (nominate) violaceus. I am certain that these represent misidentifications of the songs of Trogon curucui, an easy and natural error for observers familiar with the songs of violaceus from Central America or the Guianan region to make. In each such recording that was accompanied by a voice announcement, the recordist reported the recorded bird as unseen, but thought to be violaceus.)
It would be interesting to check xeno-canto for this ID pitfall. And it is also a good reminder to mention whatever relevant information (e.g. 'seen', 'not seen') on the recording in the remarks field.