TITLE:
Morphometric Characterization of the Grasshopper Sparrow (Ammodramus savannarum) and Baird’s Sparrow (Ammodramus bairdii) during the Wintering Season
AUTHORS:
Daniel Sierra-Franco, Martin Emilio Pereda-Solís, José Hugo Martínez-Guerrero, Irene Ruvalcaba Ortega
KEYWORDS:
Grasshopper Sparrow, Baird’s Sparrow, Wintering, Morphometric, Body Condition Index
JOURNAL NAME:
Open Journal of Ecology,
Vol.5 No.12,
December
30,
2015
ABSTRACT: Grassland
bird populations have declined more than any other group of bird species in
North America. Some species such as the grasshopper (Ammodramus savannarum) and Baird’s sparrows (Ammodramus bairdii) are of particular conservation concern, since
they have shown negative trends in their population over the last 50 years.
Their winter ecology has only begun to be studied recently and information is
limited. The purpose of this study is to achieve the morphometric
characterization of these two grassland species during the wintering season.
The study is conducted in the Rancho Santa Teresa located in Villa Hidalgo,
Durango, Mexico and the Ecological reserve “El Uno”, located in Janos,
Chihuahua, Mexico. During winter 2013-2014, 135 birds were captured; banded and
zoometric measurements were taken such as total body weight, wing chord, tail
length, culmen, and beak depth and width. Two indices of body condition (BCI) are
also calculated. All measurements and indices are compared per species and per
sex. Both species are sexed with molecular techniques, determining 20 females
and 18 males for A. bairdii and 41
females and 56 males for A. savannarum.
All variables are significant different between species (p A. bairdii (p p p A. bairdii. The biometric data
obtained in this study can be used as reference values wintering populations of
both species.