Orthopsittaca manilata (Boddaert, 1783) (Aves: Psittacidae): abundância e atividade alimentar em relação à frutificação de Mauritia flexuosa L. f. (Arecaceae) numa vereda no Triângulo Mineiro

Abstract

Frugivorous vertebrates are regulated by fruits availability, usually seasonal. The Red-bellied Macaw, Orthopsittaca manilata (Boddaert, 1783) is specialist in Mauritia flexuosa L. f. fruits, typical palm swamp tree of Central Brazil (Savanna Biome) and other South American swamp systems (Amazonian floodplain, Llanos Venezuelan and Llanos of Mojos Bolivian). The specificity seems to be for ripe fruits, particularity the nutritive mesocarp. However, palm trees bear fruit so extended, with long period for development of fruits. Presumable, O. manilata experiment moments of shortage or complete absence of ripe fruits. Thus, their populations would be governed by the fruit stage, i.e, immature or ripe? The aim of this study was to evaluate fructification of M. flexuosa and the abundance and feeding activity of O. manilata, seeking to establish a relationship between these parameters and the presence of ripe and immature fruit. The study carried in a Mauritia flexuosa path with approximately 4,5 km of extension, in Uberlandia-MG, among Nov. 2007 and Nov. 2008. We monitored 57 feminine palm trees in nine points (radius = 30 m), equidistant in 200 m. In each plant, we verified the presence of immature and ripe fruits and its estimate quantities by direct counting. We evaluated O. manilata in 17 points, including the nine of phonological evaluation, monitored during 10 min, between 07:00 and 11:00 h. Mauritia flexuosa fructified along the study. However, the ripening of the fruits was slow, six to eight months, and ripe fruits (5.743,16/planta) they were available for only five months. The abundance of O. manilata was larger in the presence of ripe fruits (Mann-Whitney test: U13 = 5,50, P = 0,03), when 82% of feeding bouts (n = 59). Their abundance and feeding also intensified, as ripe fruits were made available (Spearman Rank Correlation: P << 0,05). The pattern of fruit in a place seems to occur in regional scale - the fruiting synchrony between patches of palm in a large region Apparently, in South American scale, it is erratic - ripe fruits available in different season. The reduction in the abundance of O. manilata during presence of immature fruits, suggests that individuals accomplish seasonal movements of long distance, to consume mesocarp in ripe fruits of M. flexuosa.