Biología alimentaria de Syrigma sibilatrix (Aves: Ardeidae) en un humedal del Río Paraná Medio, Argentina

LEÓN, E. J.; SIMONETTI, PÍA; LORENZÓN, R.E.; OLGUIN, PAMELA F.; BELTZER A.H

Cuadernos de Investigación UNED

Universidad Estatal a Distancia de Costa Rica

Año: 2017 vol. 9 p. 91 - 96

1659-4266

Feeding Biology of Syrigma sibilatrix (Birds: Ardeidae)in a wetland of the Middle Parana River, Argentina. The whistlingheron (Syrigma sibilatrix) is a neotropical species that inhabits aquaticenvironments, rural areas and groves. We studied the diet of 19 birdsin Carabajal Island (31°39´S, 60°42´W) from 1999 to 2003. The trophicspectrum was composed of 14 taxonomic units of animal taxa. Trophicdiversity ranged between 0.23 and 2.15. Index of relative importancewas of 10780 for insects, 1800 for arachnids and crustaceans, and1750 for vertebrates. Most of the prey were represented by individualsincluded in the 0-20 mm (45%) and 21-40 mm (35%) size intervals.Trophic niche breadth was of 1.98 in spring, 2.34 in summer, 2.21 inautumn, and 1.99 in winter; standardized values were of 0.075 in spring,0.10 in summer, 0.09 in autumn, and 0.076 in winter. Feeding efficiencywas 96.01% in spring, 98.3% in summer, 89.9% in autumn and 92.34%in winter. No evidence was found of food selectivity. The highest percentageof site fidelity (69%) corresponded to the grassland environment.In the floodplain of the Middle Parana River, S. sibilatrix primarilyfeeds on insects from grasslands.