Proposal (122) to South American Classification Committee
Split Veniliornis chocoensis from V. affinis
Effect on South American CL: This would elevate a taxon to species rank that that we treat as a subspecies of a species on our list.
Background: The taxon chocoensis was formerly (e.g., Peters 1948, Meyer de Schauensee 1970, Hilty & Brown 1986) regarded as a subspecies of Veniliornis cassini, but it was transferred to V. affinis by Short (1974, 1982).
New information: Relatively recently, chocoensis has been treated as a separate species ("Choco Woodpecker") from V. affinis by Sibley & Monroe (1990), Winkler et al. (1995), Ridgely & Greenfield (2001), and Winkler & Christie (2002), but little evidence is published to support this; chocoensis differs from V. affinis and V. cassini only in minor plumage details. Winkler et al. (1995) treated it as a species without comment.
from Ridgely & Greenfield (2001):
"... we conclude that it is better regarded as a separate monotypic species on the basis of its distinct plumage differences from either [cassini or affinis], as well as its smaller size and disjunct range."
from Winkler & Christie (2002):
"Has often been treated as conspecific with [cassini or affinis], but differs in plumage details, in size and in habitat preferences, apparently also vocally, and is separate from both by the Andes chain."
It is not clear from Winkler & Christie (2002) what the difference in habitat preference is, at least from V. affinis. As for voice, they stated: "Details apparently not documented, but said to differ to some extent from V. cassini and V. affinis." As for size, it appears that chocoensis is smaller, but no real data have been presented to show whether there is or is not overlap (and given the radical differences in body size within populations of the same species, e.g., Pitangus sulphuratus, I'm unsure why such a difference "matters" between allopatric populations). As for plumage differences, I'm not impressed -- see the plates in the Winkler references.
Analysis: This split is supported by no data that could be considered convincing, in my opinion. On the other hand, the geographic distance between chocoensis and either affinis or cassini is impressive and of interest, and affinis and cassini themselves do not differ that much in plumage. I think the best case for a YES vote would be that I would say that it is still an open question as to whether chocoensis belongs with affinis or cassini [I am also puzzled by the apparent geographic overlap with chocoensis and V. kirkii, which all sources consider as part of the cassini-affini superspecies/complex. something is clearly wrong there in terms of superspecies designations. Someone needs to sort this out.]
Recommendation: I don't have a recommendation on this one ... I could go either way depending on others' comments. This proposal was written just to stimulate discussion of the issue.
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. 1970. A guide to the birds of South America. Livingston Publishing Co., Wynnewood, Pennsylvania.
PETERS, J. L. 1948. Check-list of birds of the world, vol. 6. Harvard University Press, Cambridge, Massachusetts.
RIDGELY , R. S., AND P. J. GREENFIELD. 2001. The birds of Ecuador. Cornell University Press, Ithaca, New York.
SHORT, L. L., JR. 1974. Relationships of Veniliornis "cassini" caquetanus and V. "cassini" chocoensis with V. affinis. Auk 91: 631-634.
SHORT, L. L., JR. 1982. Woodpeckers of the world. Delaware Museum of Natural History, Greenville, Delaware.
SIBLEY, C. G., AND B. L. MONROE, JR. 1990. Distribution and taxonomy of birds of the World. Yale University Press, New Haven, Connecticut.
WINKLER, H., AND D. A. CHRISTIE. 2002. Family Picidae (woodpeckers. Pp. 296-558 in "Handbook of the Birds of the World, Vol. 7. Jacamars to woodpeckers." (J. del Hoyo et al., eds.). Lynx Edicions, Barcelona.
WINKLER, H., D. A. CHRISTIE, AND D. NURNEY. 1995. Woodpeckers. Houghton Mifflin, Boston.
Van Remsen, April 2004
Comments from Stiles: "with very little or no experience with any of these, I have nothing intelligent to say. The case is much like the preceding, but I am even less inclined to take a stand. Abstain for now, in hope."
Further Comments from Stiles: "[YES]. In the light of Mark's comments, I will vote for splitting Veniliornis chocoensis."
Comments from Robbins: "[YES] As this entire Committee appreciates there is little plumage differences between taxa that have traditionally been treated as species, i.e., kirkii, affinis, cassinii. From my experience (observed and collected) with chocoensis in northwestern Ecuador, this taxon is as different in plumage as any of the other above species-level taxa. It is darker and more boldly banded ventrally than any of the proposed relatives (affinis & cassinii). The fact of the matter is it is unclear what species group it belongs with and its distribution fits the classic biogeographic pattern, i.e., southwestern Colombia/northwestern Ecuador, of endemic species-level taxa. I recommend that it be treated as a species. For the sake of consistency, if one treats Piculus litae as a species, then chocoensis should be elevated to species level. See my comments under proposal #121."
Comments from Jaramillo: "YES. There is no good decision to be made here. Perhaps the most responsible and defendable would be to vote no, and ask for more information to be published. On the other hand, there are no good published arguments as to why these various woodpecker taxa should be lumped. It doesn't appear to me that there is good published evidence for any specific stand here. Personally, I do think that these various woodpecker forms are good species and would rather split them out and put the burden of proof on those that prefer to retain them in their various present taxonomic positions. The case with litae is different as there is some confusion as to what litae is."
Comments from Nores: "SI, pero como en el caso anterior sin mucho convencimiento ni conocimiento del tema, y basa do fundamentalmente en el comentario de Robbins."
Comments from Silva: "YES. My decision is based on Mark's comments."
Comments from Zimmer: "I vote "YES". This one is a mess. As with Piculus litae, the evidence for a split is poor, but is no worse than the evidence for keeping it with affinis or moving it to cassini. Until more analysis can be done, I would favor isolating it, rather than risk sinking it into the wrong species. I know nothing of the voice of chocoensis, but I find it difficult to accept that cassini, affinis and kirkii are all members of the same superspecies group, given how radically the three species differ from one another vocally. As Mark points out, the distribution of chocoensis conforms to a well-established biogeographic pattern of endemism. Although circumstantial, this leads me to believe that the splitters are probably right on this one."