Abundancia y distribución invernal de Ammodramus bairdii, en la región de Cuchillas de la Zarca, México

during three consecutive winters (2008-2010), we monitored grassland birds in the region of cuchillas de la zarca, in southern state of chihuahua and northern state of durango, mexico, in order to determine the abundance and distribution of baird's sparrow (ammodramus bairdii), a migratory grassland bird. the results showed that this region is very important for the species, since we estimated a population density of 59.8±14.6 ind/km2. the species was widely distributed in most of the quadrants of the study area (n=16), but we found a higher relative abundance in the central quadrants. vegetation analysis of the sites where we recorded a. bairdii suggests that there is a similarity between the non-reproductive and reproductive habitats. due to the lack of information on this species during its non-reproductive season in mexico, data we generated in this study are useful to understand some aspects of the non-reproductive ecology of baird's sparrow.