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Range DescriptionThis specieswas known from disjunct areas in north Jalisco, south Durango, and around the Distrito Federal-Morelos border, Mexico, but is now confined to the latter two areas, over 800 km apart. In this very small area, it is most regularly recorded from around El Capuln-La Cima and Santa Ana Tlacotenco, but there are other recent records from north-east of Volcn Yecahuazac, east and north of Volcns San Bartolito and Comalera, north of Volcn Tuxtepec, west of Volcn Tulmiac, north of Acopiaxco (Cabrera 1999, Cabrera and Escamilla 2000) and north-east of Coexapa (H. Gmez de Silva in litt. 1999, Oliveras de Ita et al. 2001, Oliveras de Ita and Gmez de Silva 2002). A record at Los Dinamos, Distrito Federal in 1993 (Wege and Long 1995) refers to a misidentified juvenile Song Sparrow Melospiza melodia (H. Gmez de Silva in litt. 1999). The species went unrecorded in Durango from 1951 until it was rediscovered there in 2004 (J. M. Lammertink in litt. 2009). A recent survey concluded that the species is now confined to just two locations: Ejido Ojo de Agua-El Cazador, southern Durango, where there are at least three breeding pairs concentrated in an area of 0.5 ha within an 80 ha marsh; and the fragmented grasslands of "sur del Valle de Mxico" centered around La Cima and Milpa Alta, Distrito Federal, where there are perhaps 5,380-6,150 adults equating to 2,300 breeding pairs (Oliveras de Ita and Gomez de Silva 2007, M. A. Cruz-Nieto in litt. 2008). The northern population was found to be restricted to a single locality, having disappeared from three historical sites (Oliveras de Ita and Rojas-Soto 2006).