Altitudinal migration of a passerine in the Atlantic Forest: a complex pattern arises

Migration is a captivating behavior with a long history of research. Nevertheless, altitudinal migration of birds within the Neotropics remains the least studied migration system in the world. In this talk we will discuss our ongoing efforts to fill this knowledge gap by studying the Yellow-legged Thrush Turdus flavipes. Previous evidence supports that this species performs seasonal altitudinal movements in SE Brazil while tracking fruiting pulses of Palm tree Euterpe edulis from ~0 to ~250m asl. During research on the migration of this species across a broader altitudinal range in southern Brazil (~15 to 1,100m asl), we recorded data that may shift the existing perspective on this species’ movements. By tracking the variation in temporal abundance of populations at multiple altitudes, we found evidence that this species undergoes a partial rather than an obligatory altitudinal migration. Data showed an unprecedented scenario in which populations from extreme altitudes breed independently, apparently mixing at intermediary altitudes for wintering. We discuss how some biotic and abiotic variables correlate with these movements, as well as introduce our next plans for deepen our understanding on this first case of altitudinal migration that has been studied in detail in Brazil.