Proposal (130) to South American Classification Committee
Change English name of Cistothorus platensis from "Sedge Wren" to "Grass Wren"
This will be the shortest, flimsiest proposal I've written so far.
Cistothorus platensis has been known as Sedge Wren in North American literature for 20+ years (i.e., since at least AOU 1983, with some usage back to at least Eisenmann 1955). Although suspicions abound concerning multiple species hidden in broadly defined C. platensis, especially concerning whether the North American stellaris group should be included in C. platensis, so far the only actual analysis (Mel Traylor's 1989 monograph, which has unaccountably wandered away from my files so I can't check this) found evidence for intergradation where two of the potential species-level taxa are in contact in South America (or at least lack of convincing evidence for two-species treatment -- someone please check).
Although Meyer de Schauensee (1970) and Ridgely & Tudor (1989) treated them all as conspecific, they used "Grass Wren" for South American forms. At the time of Meyer de Schauensee (1970), "Short-billed Marsh-Wren" was the official name for the species in north America, which truly did not work well for South American populations. The reason given by Ridgely & Tudor (1989) was that "Sedge" was not appropriate for South American birds, which were likely going to be split at some time in the future anyway.
Regardless of which authors are using which names, calling the South American forms "Grass Wren" without a formal split of stellaris group from them is confusing, no matter how inappropriate in terms of habitat. I recommend a NO on this proposal. Reserve "Grass Wren" for the platensis group (or one of its subgroups) for that day when we have a decent analysis for splitting off North American stellaris.
Van Remsen, August 2004
Comments from Stiles: "NO. The two names have little to choose regarding use or appropriateness, and most people can´t tell a grass from a sedge anyway... The most inclusive name for the group at this point is "Sedge Wren" so let´s stay with it, keeping "grass wren" in reserve should a split be made (at least the latter is slightly more appropriate for the páramo forms)."
Comments from Robbins: "I vote "NO" as it is premature to apply this name to any taxon until there is a thorough analysis (vocalizations, molecular) of this complex."
Comments from Nores: "No. Las poblaciones de Sudamérica habitan siempre pajonales (grassland), pero hasta tanto no se demuestre que estas poblaciones son diferentes específicamente de las de Norteamérica, parece mejor mantener el nombre de Sedge Wren."
Comments from Zimmer: "I reluctantly vote "NO". I would prefer all of these South American forms to be called "Grass Wren", because they seem so different from our North American birds (both vocally and morphologically). However, a thorough review of this entire complex is clearly needed, and until we get it, I guess it is best to keep the names as they are (although I really don't want to use this name in the Brazil book!)."
Comments from Stotz: "NO. Until Cistothorus is split, I think we are stuck with Sedge Wren. Are South American birds really more grass-associated than North American birds? Beyond which, in Australia there are ten species of fairy-wrens in the genus Amytornis called Grasswrens (no hyphen), so I think Grass-Wren probably should be ruled out for South American Cistothorus anyway."
Comments from Pacheco: "[No] Se as populações da América do Norte e América do Sul não foram (ainda) desmembradas, o bom senso recomenda que apenas um nome em inglês seja utilizado. Talvez, em caso de "split", seja necessário escolher um nome alternativo diante da colocação feita por Stotz."
Comments from Jaramillo: "NO. Retain Grass Wren for the eventual (I am a believer) split of this complex."