Energy potential of grass seeds at sites used by grassland sparrows in Northwest Mexico

The objectives of this work were i) to determine the density of seeds in the soil of Bouteloa gracilis and Panicum obtusum that are consumed by focal grassland birds collected in Cuchillas de la Zarca, Durango and Janos, Chihuahua, ii) To estimate their energy content, and iii) To quantify their energy potential. Seed samples were considered to achieve these objectives. Variables were analyzed using the Kruskal-Wallis test. The caloric content of seeds collected in Cuchillas de la Zarca, Durango (3 650.3 Kcal∙kg DM-1) was significantly higher than those collected in Janos, Chihuahua (3 520.8 Kcal∙kg DM-1). Individuals of Ammodramus savannarum species prefer to visit sites with higher seed density and energy potential than those of Centronyx bairdii species. Variables not included in the present study, such as rainfall and vegetation structure, should be considered in future studies.