Get reliable rangeland science

The Worthen sparrow is an endemic and endangered species restricted to the Mexican plateau. It occurs at ecotone zone between the microphillum scrubland and prairie dog colonies. Most of its ecological information has been generated at marginal habitats such as overgrazed shrubland-grasslands. Rancho Los Angeles owned by Universidad Autonoma Agraria Antonio Narro is a unique private and managed grassland area into the prairie dog colony complex in Coahuila state. In 2010, a new management grazing scheme was initiated in order to promote habitat heterogeneity for grassland bird conservation. In 2013, 2014, and 2015 we found 43, 74 and 70 nests, respectively, with a total of 187 nests occupying five different cattle pastures. Nests substrate, nest site characterization, reproduction success, causes of mortality on nestlings and nest material construction were evaluated. The most preferred nest substrate was Mariola (Parthenium incanum) and Tarbush (Flourensia cernua), both representing at least the 90% of substrate species. Brush canopy cover around the nest decreases as distance increases, and brush density increases as distances increases. Using remote cameras, 6 mortality causes were recorded. Road runner (Geococcyx californianus) was the main predator with 4 events, following of snakes (Pituophis deppei) with 2 events, white footed mice (Peromyscus leucophus) and ants with 2 events, respectively, Bobcat (Lynx rufus) and hypothermia with one event, respectively. Regarding nest construction material, ring muhly (Muhlenbergia torreyi) occupies at least 93% of nest material. Another 10 grass and herb species were found with no more than 1%, including horse and cow hair.