Authors : G. Jose Hugo Martinez, Christian Wehenkel, Martin E. Pereda Solis, Jose Javier Corral-Rivas, Federico Rosales Alferez and Hector Herrera Casio
Abstract: Researchers evaluated the usefulness of two statistical methods, not used in ornithological studies to measure associations between granivorous grassland bird species and between the same species and seven different vegetation characteristics. The study was carried out in winter in the region of Cuchillas de la Zarca in Northwestern Mexico. Kendall�s coefficient showed little consistency in the determinations and only 2.19% of the associations between species were significant (p<0.05). Ammodramus bairdii, Ammodramus savannarum and Sturnella magna were positively and significantly associated as were Aimophila cassini and Passerculus sandwichensis. Gregorius�s method was more consistent in determining the association (A) between Granivorous grassland birds (α) and vegetation features (β) with 48.9% of the estimations being significant. A total of 12 species were associated with shrub height, 7 with grass height, 19 with herbaceous height, 13 with shrub cover, 16 with grass cover, 18 with herbaceous cover and 14 with other types of cover such as superficial decomposing organic material. Researchers conclude that these statistical methods may be of greater utility in ornithological studies than their historical absence from this branch of biology indicates.
G. Jose Hugo Martinez, Christian Wehenkel, Martin E. Pereda Solis, Jose Javier Corral-Rivas, Federico Rosales Alferez and Hector Herrera Casio, 2010. Measuring Associations Between Granivorous grassland Bird Species and Between the Bird Species and Winter Habitat in Northwestern Mexico. Research Journal of Biological Sciences, 5: 713-721.