LONGITUDINAL AND CYCLIC POLEWARD MIGRATION OF A SOUTH AMERICAN INTRATROPICAL MIGRANT FLYCATCHER, THE LESSER ELAENIA (ELAENIA CHIRIQUENSIS)
Keywords:Brazil, geolocators, migratory connectivity, migration route, wintering ground
Research on terrestrial migratory birds is incipient in Brazil. Geolocators have recently allowed tracking small migratory passerines, and such data combined with intrinsic markers such as stable isotopes has become invaluable in revealing migratory behavior. Here we used data from a long-term banding program in a Cerrado reserve in central Brazil where we also deployed geolocators to track adults of a 15g flycatcher, the Lesser Elaenia (Elaenia chiriquensis). The literature defines it as a resident or migrant that may overwinter in the Amazon or Central Brazil. Our general goals were to describe the breeding site fidelity of individuals, their migratory behavior and wintering grounds, thus assessing the migratory connectivity of the studied population. We tagged 40 birds in 2011-2012 and successfully extracted data for three recaptured individuals. We analyzed data using GeoLight and QGIS. Recapture data showed that individuals lived for at least 12yrs and that ~15% of all marked birds returned to a ~200 ± 185m radius from where it was recorded in a previous breeding season. Tracking data revealed low migratory connectivity of the studied population. One individual remained resident. The other two individuals migrated through distinct routes: one made a longitudinal northeast-southwest route and the other a cyclic migration consisting of a poleward section to south Brazil, a NW flight to the Pantanal surroundings and ending with a longitudinal NE spring migration. These are the first detailed data of the migratory movements of individual Lesser Elaenias, supporting its partial rather than obligatory migration in central Brazil. Moreover, we found that migrants overwintered in savanna-like areas, supporting previous studies. We included and discussed a list of hypotheses we expect to guide further studies on this and other intratropical migrant species, thus contributing to improving knowledge on this complex and understudied migratory system.