Association of Ammodramus bairdii A. 1844, and Other Species of Grassland Granivorous Birds in Winter Time in Northwestern Mexico

Abstract

During the winter of 2009 grassland birds were monitored in the region of Cuchillas de la Zarca to estimate the association between Ammodramus bairdii Audubon 1844, focal species of grassland and bird species belonging to the trophic guild of grassland granivorous birds (n = 25 ). The study area was divided into monitoring quadrants (n = 16) where 96 transects for bird monitoring were conducted, recording 16,635 individuals of which only 32.9% were in the trophic guild of grassland granivorous birds. The association between A. bairdii and other species was estimated from the nonparametric statistical index of Kendall’s coefficient of concordance (W) and the p value, through permutation analysis (n = 10,000), finding positive and significant associations (p ≤ 0.05) of the target species for study with Sturnella magna, Passerculus sandwichensis and Ammodramus savannarum, species that share habitat preferences of natural grassland in good condition, slightly grazed and with little tolerance to the shrub cover. The association W ranged from 0.072 and 0.749. These results can recognize this region as an important area for the conservation of obligate grassland birds during winter, suggesting establish training programs to better utilize this resource by means of cattle activity.