Proposal (#40) to South American Check-list Committee:

 

Split Hyloctistes virgatus from H. subulatus

 

Effect on South American CL: This proposal would elevate a taxon to species rank that we currently treat as a subspecies on our baseline list.

Background: For most of its history, Hyloctistes subulatus (Striped Woodhaunter) has been considered to be a single, polytypic species. Recent descriptions of vocalizations, however, indicate that the six subspecies fall into two vocal groups: (1) virgatus group of Central America + Chocó , and (2) subulatus group east of Andes. Placement of cordobae is evidently with virgatus based on plumage. Below is the classification I used in HBW (Remsen 2003):

H. s. nicaraguae Miller & Griscom, 1925 - E Nicaragua.
H. s. virgatus (Lawrence, 1867) - Costa Rica, W Panama (east to Veraguas).
H. s. assimilis (Berlepsch & Taczanowski, 1884) - E Panama (E Colon west) to W Colombia south to W Ecuador (NW Azuay, El Oro).
H. s. cordobae Meyer de Schauensee, 1960 - N and C Colombia (Antioquia, S Córdoba, and in Magdalena Valley south to Boyacá).
H. s. lemae Phelps & Phelps, 1960 - SE Venezuela (Sierra de Lema in SE Bolívar).
H. s. subulatus (Spix, 1824) - S Venezuela (Amazonas, S Bolívar), SE Colombia (S Meta and Vaupés south), E Ecuador, E Peru, N Bolivia (to La Paz, Beni), and Amazonian Brazil (east to Pará; mostly south of Amazon and west of Rio Negro).

Although quantitative data lacking, each of the six subspecies may be 100% diagnosable based on plumage characters. Nevertheless, there seems to be a quantum differences between the two groups, with the virgatus group much darker ventrally with less conspicuous markings and dorsally nearly devoid of streaks. Although a formal analysis with sonograms has not been published, qualitative descriptions of songs strongly suggest major differences. Here is my synopsis from HBW, which was condensed from descriptions in Hilty & Brown (1986), Stiles & Skutch (1989), Ridgely & Tudor (1994), and Ridgely & Greenfield (2001):

"Song (virgatus group) described as a series of variable length of loud, sharp nasal notes "kip, yip-yip-yip-yip-yip." or "keeu-keeu-keeu-keuu " or "kick-kick-kick " , evenly pitched and spaced. Song (subulatus group) starts with two (occasionally up to 4) loud whistled "tyew" or "tseew" notes followed by a softer, low-pitched rattling "tr-r-r-r-r-r." Sometimes just gives a series of 2-5 of the "tseew" notes. Call note of both groups similar, a sharp, raspy "chook,", "squirk" or "squirp!" In Costa Rica, a dry chattered "zeck-zeck-zeck " also described."

Cory & Hellmayr (1925), Peters (1951), Meyer de Schauensee (1966, 1970), Vaurie (1980), Hilty & Brown (1986), and Sibley & Monroe (1990) treated them as conspecific. Ridgely & Tudor (1994) considered them conspecific but that vocal differences on opposite sides of the Andes suggested that more than one species was involved. Ridgely & Greenfield (2001) considered them as two separate species ("Eastern Woodhaunter" and "Western Woodhaunter") based primarily on descriptions of voices, and this was followed by Hilty (2002). Remsen (2003) maintained them as conspecific and noted that two species are almost certainly involved.

Analysis: This one presents a difficult choice. The qualitative differences in voice are so great that I suspect chances are high that an in-depth analysis would only confirm what we already know in terms of two very different vocal groups. More generally, the biogeographic split represented by these two taxa is consistently appearing as a deep genetic split in lowland tropical lineages, and I suspect that few interior forest "species" showing this split will survive taxonomically as single species. Therefore, in my opinion, it all comes down to whether the published qualitative descriptions are sufficient evidence to support a split and to put "burden of proof" on those who would maintain a 1-species treatment. After all, we have plenty of taxa maintained as separate species based solely on historical tradition, without even a qualitative comparison of voices. On the other hand, one could argue that enforcement of minimum standards for taxonomic changes of this sort is desirable, e.g., at least a short paper with sonograms from key points in the ranges of both subspecies groups. Placement of cordobae would also be of interest (maybe Gary knows its voice), although not absolutely critical for the split.

Recommendation: I will very reluctantly vote "NO" on this proposal only because I think that there is value in requiring some minimum standards of published data for making taxonomic changes. This is particularly important, in my opinion, when instituting novel species-level taxonomy, i.e., as in this case, when we are not reversing an unjustified lump by say, Peters' checklist. Furthermore, it would not take much effort to publish a note with a few representative sonograms in a journal ranging from Auk to Cotinga outlining the rationale for treatment as separate species, similar, for example, to Sjoerd Mayer's note in the Auk on Rhynchotus, which was the basis of one of the first changes in species limits that we made to the SACC list

Literature Cited:

CORY, C. B., AND C. E. HELLMAYR. 1925. Catalogue of birds of the Americas Field Mus. Nat. Hist. Publ., Zool. Ser., vol. 13, pt. 4.

HILTY, S. L. 2003. Birds of Venezuela. Princeton University Press, Princeton, New Jersey.

HILTY, S. L., AND W. L. BROWN. 1986. A guide to the birds of Colombia. Princeton University Press, Princeton, New Jersey.

MEYER DE SCHAUENSEE, R. 1966. The species of birds of South America and their distribution. Livingston Publishing Co., Narberth, Pennsylvania.

MEYER DE SCHAUENSEE, R. 1970. A guide to the birds of South America. Livingston Publishing Co., Wynnewood, Pennsylvania.

PETERS, J. L. 1951. Check-list of birds of the world, vol. 7. Museum of Comparative Zoology, Cambridge, Massachusetts.

REMSEN, J. V., JR. 2003 (in press). Family Furnariidae (ovenbirds). Pp. #-# in "Handbook of the Birds of the World," Vol. 8. Broadbills to Tapaculos (del Hoyo, J. et al., eds.). Lynx Edicions, Barcelona.

RIDGELY, R. S., AND G. TUDOR. 1994. The birds of South America, vol. 2. Univ. Texas Press, Austin.

RIDGELY , R. S., AND P. J. GREENFIELD. 2001. The birds of Ecuador. Vol. I. Status, distribution, and taxonomy. Cornell University Press, Ithaca, New York.

SIBLEY, C. G., AND B. L. MONROE, JR. 1990. Distribution and taxonomy of birds of the World. Yale University Press, New Haven, Connecticut.

VAURIE, C. 1980. Taxonomy and geographical distribution of the Furnariidae (Aves, Passeriformes). Bulletin of the American Museum of Natural History 166: 1-357.

 

Van Remsen, July 2003

P.S.: If the proposal passes, then I'll work on another one on the English names of these two.

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Comments from Schulenberg: "My vote: "No". My understanding is that Kevin Zimmer is working on a vocal (and morphometric?) analysis of this genus, so soon we may have a proper study to cite: something that almost surely *would* endorse the idea of splitting these two taxa. "

Comments from Robbins: "YES, as the voices are quite different. I thought Kevin Zimmer was writing this up?"

Comments from Stotz: "Split. The voices of these things are really different."

Comments from Zimmer: "I vote "yes" on the proposed split of Hyloctistes. As suggested by Tom and Mark, this is something that I've had simmering on the back burner for a couple of years. I have to confess that Ridgely and Greenfield summarily splitting the complex took some of the momentum out of my project (well, that and trying to finish my HBW chapter!), but I do agree with their results. The "species" clearly breaks down into two very distinctive groups based on voice (this is assuming cordobae belongs with the western group). I have morphometric data on probably 200+ specimens
plus bunches of tape recordings from throughout most of the range. It probably wouldn't take a lot to write this up, especially if I pass on a full-fledged quantitative analysis of the vocal differences, which are stark enough that I don't believe such an analysis is called for. I'll try to get on this soon, but in the meantime, I think the qualitative descriptions of voice that have been published are enough to support going ahead and splitting. Ridgely's suggested English names make sense to me."

Comments from Stiles: "NO. In this case while I definitely agree with the proposal, having had experience with the forms, I don´t have sonagrams (etc.) and will suspend personal opinion in the interests of being consistent with stated principles. I agree personally but prefer to maintain a standard. As an aside, the voice of cordobae is sufficiently similar to the Costa Rican bird that I recognized it immediately - but I don´t have sonagrams!"

Comments from Silva: "No. It seems to be a complex case, with several biological and phylogenetic species involved. Thus, I would prefer to see a study formally splitting the evolutionary unities based on morphology and voice."

Comments from Jaramillo: "YES ­ Perhaps I should vote no, knowing that a good analysis will be forthcoming. However, that will take time, and qualitative vocal data exists that suggests that two species are clearly involved. Voice data matches up to the main division in plumage pattern. This makes me feel that the burden of proof be put in the camp of those that want to lump these two taxa. I must admit that I would be more hesitant if I didn't have the information that Kevin was working on this and the informal results he gave."