For those who have traveled down south and have seen a “Sedge Wren” in South America, you may have the opinion that those things down there are nothing like the Sedge Wren of the north. Well, you would have been right in your assertion. For some time the name Grass Wren was given to anything that was not the classic North American Sedge Wren, but it turns out to be even more nuanced than that.
A paper by Mark Robbins and Arpad Nyari published December 2014 (The Wilson Journal of Ornithology 126(4):649–662, 2014) clarifies the relationship of the various Sedge Wren forms. They used data from nuclear and mitochondrial DNA to put together a hypothesis for the relationships in the group, in addition they also analyzed vocalizations of the various forms. Their analysis found that the Apolinar’s and Merida wrens of Colombia and Venezuela were part of this complex, and embedded within it. Their data suggest that including these two species there are a whopping 11 species!! Robbins and Nyari make a plea for temperate grassland conservation, stating that many of these species are either very rare and restricted now, or have had massive population drops since large scale grazing and agriculture altered the landscape.
Wrens will be the new tapaculos. Keep your eyes out on House Wren, as there likely be a similar number of suggested splits in the future. It may even be more complex with the House Wrens. Marsh Wren is two species in North America, and it is not impossible that we have more than one Bewick’s Wren in the continent. Watch the wrens in the coming years. Below are the suggested species in the complex.
Cistothorus stellaris – Sedge Wren. This is the one we find in the United States and Canada.
Cistothorus meridae – Merida Wren. Venezuela.
Cistothorus apolinari – Apolinar’s Wren. Colombia.
Cistothorus elegans – Grass Wren. Highlands of Mexico to Panama.
Cistothorus hornensis – Austral Wren. Chile, Patagonia, and the Falklands. This is the bird pictured above, the southernmost in the group, and one that has a relatively short tail.
Cistothorus tucumanus – Tucuman Wren. Santa Cruz, Bolivia south to Cordoba, Argentina.
Cistothorus platensis – Pampas Wren. Note that this is the species that will carry the original name, platensis, as it was the first named based on the Rio de la Plata. Lowlands of Bolivia east through Paraguay and S Brazil south through Uruguay to central Argentina.
Cistothorus minimus – Puna Wren. Ayacucho Peru to Altiplano of Bolivia.
Cistothorus graminicola – Junin Wren. Highlands of N Peru, Junin.
Cistothorus aequatorialis – Paramo Wren. Paramos of Andean Venezuela, Colombia south to N Peru.
Cistothorus alticola – Venezuelan Wren. Tepuis of Venezuela.