Bird visits and resource use in Butia odorata (Arecaceae) palm groves in southern Brazil

Abstract

We evaluated avian use of a palm grove of Butia odorata (Barb. Rodr.) Noblick in the Brazilian Pampa. We recorded bird species richness, frequency of visits, and feeding behavior in palms trees with different flower and fruit availability. From January 2018 to February 2019, we observed 1,094 bird visits in 347 palm trees and identified 53 species. The most frequent visitors were Sicalis flaveola (Linnaeus, 1766), Myiopsitta monachus (Boddaert, 1783) and Zonotrichia capensis (Statius Muller, 1776). Perching was the most frequent use of palm trees by the birds (79%). Our hypothesis that an increase in the availability of flowers and fruits will be followed by a larger number of visits by insectivorous and frugivorous birds was not corroborated. In addition, there was a higher number of species visiting palm trees with no resources. The species composition and the number of guilds of visiting birds varied seasonally, but independently from resources availability. Bird richness, number of visits, and time length of visits did not vary between flowering/fruiting and resourceless palm trees. Based on this we argue that the main contribution of Butia odorata to the establishment of bird assemblages in palm groves is their role in offering perching, sheltering, and nesting sites.