Migratory timing rate, routes and wintering areas of White-crested Elaenia (Elaenia albiceps chilensis), a key seed disperser for Patagonian forest regeneration

BRAVO, S.P.; CUETO, V.R.; GOROSITO, C.A.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2017

1932-6203

Inorder to design management strategies to conserve migratory birds and theirecosystem functions, it is essential to understand their full annual cycle.Migratory routes and timing of most Neotropical austral migrants, which breedat south temperate latitudes of South America and overwinter closer to orwithin tropical latitudes of South America, have yet to be described in detail.White-crested Elaenia (Elaenia albicepschilensis) breeds in the Patagonian Forest biome, and is probably theaustral migrant that migrates the longest distance.  White-crested Elaenia plays a relevant rolein forest regeneration and is also important for the control of insectherbivory. Our objective was to describe the annual cycle of White-crestedElaenia, determining their migrationtiming, rate and routes, and identifying critical areas this species depends onoutside of the breeding season. Fifteen individuals were successfully trackedthroughout a complete migration cycle using small light-level geolocators. Allindividuals resided and moved through the same general regions. During fall(March-April-May) elaenias were located in the Caatinga and the Atlantic Forestbiomes, north of Rio de Janeiro to the region near Salvador da Bahia, Brazil.During winter (June-July- Aug.), birds were in inland Brazil, in the Cerradobiome. Birds used three different routes during fall migration. Our resultsindicate that some individuals use a direct route, flying between 500-600km/day, crossing desert and grasslands, while others take a detour, flying100-200 km/day through forested areas with refueling opportunities. All birds usedthe same forest route during spring migration, with ten out 15 individualsshowed clear counterclockwise loop trajectories throughout their annual cycle.None of the elaenias used Amazonia, traveled to western South America orcrossed the Equator.  Our results suggestthat the Yungas biome in Argentina may be critical for the long-term populationconservation of White-crested Elaenia, because it may be mainly used by femalesand juveniles during fall migration, and by all elaenias during spring migration.