Biologia reprodutiva de Elaenia cristata (Aves: Tyrannidae) em cerrado do Brasil central

Abstract

Reproduction is a fundamental biological process to animal life histories and includes risks which affect the survival of breeding adults. Considering that information about Elaenia cristata reproduction biology is lacking, we aimed in this study to describe some aspects related to its reproduction. We carried out this study from 2002 to 2007 at “Estacao Ecologica de Aguas Emendadas” (ESEC-AE) and its surroundings, within the Cerrado biome, Distrito Federal, Brazil. We monitored 89 nests every 2-4 days. The breeding season started in September, had a peak in October and lasted until early December, with an average length of 99 days. Elaenia cristata builds its open cup nests on a fork. Clutch size was mostly of two eggs (n = 50). Its eggs are white with or without small brownish dots around the obtuse end. Egg length and width (n = 7) averaged 20.2 ± 0.1 mm and 15.1 ± 0.1 mm, respectively. Nest height above the ground (n = 87) averaged 1.5 ± 0.8 m, most of them on Davilla elliptica. Cerrado sensu strictu was the habitat most used (61%) for nest building. The incubation period averaged 15.2 ± 0.5 days (n = 9), while the nestling period averaged 16.4 ± 0.4 days (n = 17). Egg success was 31.4% and mean hatching rate was 0.95 ± 0.1. Overall productivity was 0.5 ± 0.5 fl edgling per nest, and fecundity rate was 0.9 ± 0.6 fl edgling per female. Nineteen nests were successful (27%) and 51 were depredated (73%). Predation rate during the incubation phase (71%) was higher than during the nestling phase (29%), contrary to the pattern found in most birds. However, the other reproductive aspects are similar to those described for its congeners, other flycatchers or most Neotropical passerines