Low reproductive success of Campo Suiriri (Suiriri affinis) and Chapada Flycatcher (S. islerorum) in the central Brazilian Cerrado

Abstract

We investigated the reproductive success of Campo Suiriri (Suiriri affinis) and Chapada Flycatcher (S. islerorum) in the Estação Ecológica de Águas Emendadas, Central Brazil. Between June and December 2003, we monitored 25 nests of Campo Suiriri and 20 nests of Chapada Flycatcher. The simple percentage of successful nests was 32% for Campo Suiriri and 10% for Chapada Flycatcher, whereas the reproductive success calculated by the Mayfield method was 19% for Campo Suiriri and 14% for Chapada Flycatcher. The estimated values of daily survivorship rate (DSR) for Campo Suiriri are as follows: egg period 0.971 and nestling period 0.944. For Chapada Flycatcher the figures were 0.964 and 0.930, respectively. No differences in DSRs between species or periods were statistically significant. All nest losses of Campo Suiriri were due to predation, while for Chapada Flycatcher predation accounted for 78% of nest losses and the remaining 22% was due to parasitism by botfly larvae (Philornis sp.). The low reproductive success of Chapada Flycatcher is close to the lowest values recorded for Neotropical birds and might be a threat to this species and an important variable in the determination of its conservation status.