Timing of Migration and Breeding of the Lesser Elaenia (Elaenia chiriquensis) in a Neotropical Savanna

Abstract

We studied the Lesser Elaenia (Elaenia chiriquensis) to understand temporal patterns of occurrence and breeding of an intratropical migrant in a highly seasonal savanna (Cerrado). We tested the hypotheses that: (1) occurrence of the Lesser Elaenia in breeding areas is long, as expected for a migrant breeding in the Neotropics, and (2) the breeding period is also lengthy, as the breeding window increases in tropical latitudes. We recorded the abundance of individuals (n = 5,603 records) and nests (n = 502) during three breeding seasons (2005–2007). The Lesser Elaenia occurred in the study area during a 4.5-month period (between Aug and Dec = 132 days), but was abundant during a shorter period (105 days). An interval of 2.5 months (77 days) occurred between the first and last egg-laying dates, concentrated in a shorter interval (63 days). The occurrence period of the Lesser Elaenia in the Cerrado was one of the shortest recorded for a neotropical migratory flycatcher and was most similar to other congeneric species that breed at higher latitudes. The breeding period in this tropical seasonal environment may be intermediary between the humid tropics and the south temperate region.