Proposal (1) to
Elevate Rhynchotus maculicollis to species rank
Effect on South American CL: this proposal would split the Red-winged Tinamou, Rhynchotus rufescens, into two species, R. rufescens and R. maculicollis.
Background: The subspecies of Rhynchotus rufescens (Red-winged Tinamou) that inhabits the foothills of the Andes of Bolivia and NW Argentina, R. m. maculicollis, has been treated at the subspecies rank during this century by Peters (1931), Meyer de Schauensee (1966, 1970), Blake (1977), Sibley and Monroe (1990), Handbook of the Birds of the World, etc.
New information: Maijer (1996: Auk 113: 695-697), however, provided data on primary vocalizations that suggests that this taxon merits species rank. His rationale was as follows: (1) songs of tinamou taxa currently treated as species are surprisingly uniform (citing Hardy, Vielliard, and Straneck ARA cassette); (2) songs of the three lowland subspecies of R. rufescens are differ in only minor ways, perhaps only individual variation (based on his limited experience); and (3) the difference between maculicollis and lowland rufescens is substantial; to quote Maijer: "the song differences between maculicollis and lowland populations of R. rufescens are as great as between closely related species in other tinamou genera (pers. obs.)". Maijer compared tape maculicollis from 5 individuals from 4 widely separated areas of Bolivia to single representative recordings of lowland rufescens from the three named subspecies (from Bahia, Huanchaca, and Entre Rios) to quantitatively demonstrate the differences. Maijer noted that the foothills and lowlands populations are probably allopatric, separated by unsuitable (forest) habitat.
Recommendation: We could easily fault Maijer for not having larger and broader samples, for not evaluating whether the closest rufescens populations approach maculicollis in voice, and for not quantifying his statements on within-species vocal variation in other tinamous. However, such criticisms could be leveled at almost any new data set, and if we set our standards that high, we might as well endorse 99% of the status quo and all go home. Furthermore, our current status-quo taxonomy is based on much less. For example, Peters or whoever started treating maculicollis as a subspecies probably lumped it into rufescens without so much as a comment. From my experience on the AOU CLC, this example will be a typical dilemma for us: retain a status quo often based on unstated rationale or opinions versus accept a novel change backed by data that is often far below what we'd hope for. Unfortunately, a dissertation-quality study cannot be undertaken on every taxonomic problem.
Therefore, I favor following Maijer for the following reasons: despite limited sampling in terms of individuals, it is geographically fairly extensive, and I have no reason to suspect that more complete sampling would alter the conclusions. The sonograms indicate that indeed there is a major difference between the two proposed species. I do not have sufficient direct experience to evaluate the statement attributed to Hardy et al. concerning within-species variation in other tinamous. Philosophically, my position is that if we recognize maculicollis, then we at least have one pair of tinamou allospecies for which their taxonomic rank is supported by a published, peer-reviewed paper ... which differs strongly, for example, for the current status-quo taxonomy of that set of Crypturellus species from duidae through kerriae and their Middle American relatives.
English names: Maijer recommended "Huayco Tinamou" for R. maculicollis, the onomatopoetic local name for the bird in Bolivia. I like this, but I do not think we should be constrained by published preferences for novel taxa. Another possibility, less colorful but perhaps more informative than the above, might be "Foothill Tinamou." Some "common name" purists out there might insist that we use a compound name, like "Huayco Red-winged Tinamou" and "Lowland Red-winged Tinamou." On the AOU CLC, we tend to use these compound names, or invent a new name for both taxa (reserving the old name for the superspecies) when the taxonomic split divides the original species into two major populations. However, when the split involves a peripheral isolate of a widespread form, we tend to retain the "old" name for the widespread one and invent a new one for the peripheral isolate (e.g., Red-winged and Red-shouldered blackbirds). In my opinion, the Rhynchotus situation is a better match for the latter. Therefore, I propose we go with "Red-winged Tinamou" and "Huayco Tinamou."
Van Remsen, 4 Oct. 2000
Comments from Stiles: "I have no experience with the taxa involved. However, my experience with several other tinamou taxa has been that voice, while not necessarily absolutely invariant, is much more constant than details of plumage over wide geographical areas in several species. Hence, I would be more willing to split a tinamou species on the basis of pronounced vocal differences than differences in plumage, all other things being equal. How did Maijer identify his foothill birds? Did he take specimens to serve as vouchers for the vocalizations? (in other words, is there no doubt that what he recorded is maculicollis?) If this is the case, my personal bias would be to recognize maculicollis as a separate species as per Van's recommendation. Regarding English names, I have no strong preferences in this case. It seems that, for consistency, if three-word names are to be employed, the choices would be Foothill Red-winged T. and Lowland Red-winged T.; with two-word names, Huayco and Red.-winged Ts would do . I don't care for Foothill T. "a secas" as there are several other tinamou taxa that are essentially foothill birds.
Comments from Nores: "NO. Although Maijer reasons seem valid, I think that the differences in song are not enough to elevate maculicollis to species rank to. In the field the songs do not sound too different.”
Comments from Jaramillo: "YES. My vote is to do so, elevate Rhynchotus maculicollis to species rank and give it the English name Huayco Tinamou. I have heard and seen many individuals of R. rufescens from southern Buenos Aires province, to Santa Cruz Bolivia and at several sites in between. Their vocalizations vary somewhat individually but there is no clear geographic pattern that I have detected at least through casual observation/listening. However, the shift in song from rufescens to maculicollis is clear, unambiguous and distinct. Rhynchotus rufescens gives a melancholy series of whistles, usually three, the first one longer and slurred the last two shorter and descending: "Pheeew weeu weeu". In contrast, R. maculicollis gives a sharp, quick two syllable whistle that is slurred together the first part ascending the second more even in frequency: "Wheee- cooo!" I have heard the two taxa only several days apart, rufescens in the lowlands of Santa Cruz, Bolivia and maculicollis in the highlands of Siberia, Bolivia. The differences in vocalization and habitat were striking, furthermore there were no representatives of Rhynchotus in intermediate elevations. Apparently the same distinction is seen in Argentina in the Calilegua area highlands (maculicollis) and Salta/Jujuy lowlands (rufescens) and Sierra de Aconquija (maculicollis) and Tucuman lowlands (rufescens) without any intermediate populations. I do not like the name Foothills Tinamou for maculicollis due to the fact that it appears to inhabit areas above what I would term the foothills, being found in clearings above moist Yungas/cloud forest, so really in the lower Temperate zone, or perhaps upper subtropical. The grasslands I have heard maculicollis in Bolivia are moist, often at the fog line, and very different from the dry (or at least seasonally dry) grasslands one finds rufescens in. Based on heard calls and responses to playback, maculicollis occurs in low densities, while rufescens is often found in rather high densities. From my perspective this split seems to be a very good one.”