Jose Javier  Corral-Rivas, Martin E. Pereda  Solis, G. Jose Hugo  Martinez, Federico Rosales  Alferez, Christian  Wehenkel, Hector Herrera  Casio, 
    Measuring Associations Between <I>Granivorous grassland</I> Bird Species and Between the Bird Species and Winter Habitat in Northwestern Mexico,
    Research Journal of Biological Sciences,
    Volume 5,Issue 11,
    2010,
    Pages 713-721,
    ISSN 1815-8846,
    rjbsci.2010.713.721,
    (https://makhillpublications.co/view-article.php?doi=rjbsci.2010.713.721)
    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&lt;0.05). <I>Ammodramus bairdii</I>, <I>Ammodramus savannarum</I> and <I>Sturnella magna</I> were positively and significantly associated as were <I>Aimophila cassini</I> and <I>Passerculus sandwichensis</I>. Gregorius’s method was more consistent in determining the association (A) between <I>Granivorous grassland</I> birds (&#945;) and vegetation features (&#946;) 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.
    Keywords: Mexico;Kendall coefficient;Permutation test;vegetation attributes;Aimophila cassini;chihuahuan desert