Dieta de Penelope superciliaris Spix, 1825 (aves, cracidae) em um fragmento de mata semidecídua de altitude no sudeste brasileiro

Abstract

The feeding ecology of the frugivorous vertebrates is important, because they are responsible for the demographic establishment of most plant species. This study had the following objectives: identify, estimate and characterize the diet of Penelope superciliaris, as well as verify the potential of seed germination of the fruits ingested by those birds. The research was developed from March 1999 to October 2000 in a fragment of semideciduous altitudinal forest in the Parque Municipal do Itapetinga, in the Atibaia Municipality, São Paulo State. The diet of the birds were observed through walking transects and focal-tree methods besides collections of fecal samples in different environments of the study area. The monthly diversity of fruit species found in the fecal samples was verifíed by the Simpson diversity index. Between April and October 2002 germination experiments were accomplished with captive birds. Seasonai differences in the diet and in the germination rates between control and treated seeds and morphological characteristics of consumed fruits were compared using Chi-Square test. Twenty-fíve feeding-bouts and 23 contacts with Penelope superciliaris were obtained in the study area. The largest number of feeding-bouts and contacts were registered inside the forest in heights ranging from 5.1 to 10 m. Penelope superciliaris consumed fruits in all months (y2 = 3.16; p > 0.05) and the consumption of leaves and flowers presented two picks in the dry season (y2 = 61.42; p < 0.001). The diet of P. superciliaris was composed by fruits of 52 species of plants belonging to 27 families, besides leaves and flowers. The families Myrtaceae, Rubiaceae and Solanaceae were the most represented in the fecal samples. The number of species found monthly in the fecal samples varied from one to nine, and the diversity (Simpsom Index) varied from one to six. In April May and December 1999 and January 2000 the diversity of seeds was low in relation to the number of species. The seeds more frequently found in the fecal samples belonged to fruits of drupe (57.65%) and berry (26.67%) types, having a signifícant predominance for the first (y2 = 29.02; p < 0.05); and of red color (43.53%) and black (38.82%) (y2 = 0.68; p > 0.05). The seeds of the species Ficus enormis, Miconia cinnamomifolia and Aegiphila sellowiana presented high germination rates, after passing through the digestive tract of Penelope superciliaris, while Psychotria sessilis and Didymopanax angustissimum presented smaller rates, having the Iast species the large it rate for the control seeds. Penelope superciliaris prefers forest areas and has a great feeding flexibility, shown by the high number of plant species included in its diet. The high rates of seed germination of the species after gut treatment by the birds indicate that they can be considered potential seed dispersers of such plants.