Diet of the lesser rhea (Rhea pennata) and food availability in the Andean Precordillera (Mendoza, Argentina)

PAOLETTI, G.; PUIG, S.

Emu Austral Ornithology

Csiro Publishing

Lugar: Collingwood; Año: 2007 vol. 107 p. 52 - 58

0158-4197

The feeding strategy of Rhea pennata was studied in the high arid pampas of the Villavicencio Natural Reserve (Mendoza, Argentina). The composition and seasonal changes in the diet of the lesser rhea were analysed, as related to the availability of vegetation. The analysis of vegetation and sampling of faeces were carried out in spring, summer and autumn. Grasses dominated the vegetation, together with shrubs, whereas forbs and cactaceae showed low availability. Stones found in the faeces constituted 2.24 % of their dry weight. The main dietary component was the leaf material (94.30 %), supplemented by seeds (5.66 %) and a low proportion of insects (0.03 %). The diet included 70 % of the available plant species, with forbs and shrubs as main and preferred categories, followed by grasses and cactaceae (used with low preference and indifference, respectively). Diet diversity (0.77) surpassed environmental diversity (0.29). The diet of the lesser rhea in the Precordillera of Mendoza was almost completely herbivorous, generalist and selective, features that would constitute an adaptation to survive in this clearly arid environment. To know how the lesser rhea faces the environmental restrictions of food can be relevant for the protection of this species in strictly arid environments such as that studied.