On the migration of Elaenia albiceps chilensis (Aves: Tyrannidae) in Argentina

Abstract

We compared the biometrics, plumage, behavior, distribution and migration of Elaenia albiceps nesting along the forests of Argentina and central and southern Chile and we concluded that two forms with different phenotypes occur, one in the southern Yungas of northwestern Argentina, the other in the sub-Antarctic forests of Argentina and Chile. We found that these two forms present different patterns of migration, returning to their nesting areas by different routes. Whereas populations that nest in the southern Yungas would be migrating to the breeding area from the Pantanal in Mato Grosso through Chacoan dry forests, populations of Elaenia albiceps chilensis which nest in southern Argentina and Chile migrate from Brazil through the upland Atlantic forest of extreme northeastern Argentina. They pass through the Atlantic Forest along the Uruguay and Paraná rivers, cross the Espinal and arrive in the Monte desert of the provinces of San Juan and Mendoza, in late October and early November. Very few individuals remain in the Monte during the summer; most cross the Andes to Chile or move to the south of Argentina, where they nest primarily south of 35 degrees latitude.