Reproductive aspects of the Yellow-bellied Elaenia, Elaenia flavogaster (Tyrannidae), in the state of São Paulo, Brazil

Abstract

The Yellow-bellied Elaenia, Elaenia flavogaster, is widely distributed throughout Central and South America, yet detailed studies on its reproductive biology were conducted only in Trinidad and Tobago, Costa Rica, and Guatemala. Here, we present breeding biology information for a population of the Yellow-bellied Elaenia from Sao Paulo State, southeast Brazil, and we reveal remarkable variations in several reproductive parameters. During five breeding seasons, we analyzed 23 nests that were found from September to December. Both males and females contributed to nest construction, incubation, and nestling provisioning. Eggs were laid on consecutive days and clutch sizes averaged 2.0 ± 0.4 eggs. Incubation and nestling periods lasted 14.7 ± 1.0 and 19.5 ± 1.9 days, respectively. Nest survival probability from laying to fledging was 30%. In the populations from northern South America and Central America, breeding season and incubation periods were longer, nestling period was shorter, eggs in a clutch were laid with a 2-day interval, and only females incubated. Our data add to the findings that reproductive parameters of widely distributed species can vary among regions in the Neotropics, and the divergences were likely caused by latitudinal adaptations.