Gorosito, C. A. | Search bioRxiv

bioRxiv2024

En route activity of Chilean Elaenia, a long-distance migratory bird in South America

The logistics of measuring activities that occur at fine temporal scales, such as short stopovers that last a few hours, has proven very challenging when studying small migratory birds. Here, we deployed multi-loggers equipped with an accelerometer and thermometer on Chilean Elaenia (Elaenia chilensis) to evaluate their activity patterns while they undertook their annual migration from their Patagonian breeding grounds to non-breeding zones in Brazil. Results show that elaenias can fly at altitudes of >1500 masl and migrate nocturnally, providing the first evidence of this behavior in a Neotropical austral migrant. Although most migration flights lasted less than 8 h, one individual flew non-stop for more than 28 h. Overall activity patterns (e.g., flight and stopover duration) were not substantially different between pre- and post-breeding migration. This technology offers a window into the migratory behavior of small birds that migrate within the Neotropics at a finer temporal scale than previously possible.

ecology↗

bioRxiv2018

SEASONAL CHANGES IN BIRD ASSEMBLAGES OF A MAITENAL FOREST IN NORTH PATAGONIA

We evaluate seasonal variations at the community level, analyzing changes in species richness, species composition and total abundance, and at the species level, evaluating differences in breeding and molting seasonality among bird species in a forest-steppe ecotone of north Patagonia. The bird assemblage showed a low seasonal variation in richness and total abundance, but a great change in species composition between spring-summer and fall-winter. The change in species composition promoted few seasonal variations in richness and total abundance, because they were compensated by the presence of abundant species that visit the area in different seasons. At the species level, resident birds and short distance migrants tended to begin breeding earlier than long distance migrants, and birds began to molt body and flight feathers after breeding. Therefore, we found a low overlap of these two demanding activities. Our results highlight the importance of bird movements in response to seasonal variations in the availability of resources, which promote migration or local displacements of birds.\n\nResumen. Cambios estacionales en los ensambles de aves en un ecotono bosque-estepa del norte de PatagoniaEvaluamos las variaciones estacionales a nivel comunitario, analizando la riqueza de especies, la composicion de especies y la abundancia total, y a nivel de las especies, evaluando las diferencias en la estacionalidad reproductiva y de muda entre las especies de aves en un ecotono bosque-estepa del norte de Patagonia. El ensamble de aves mostro pocas variaciones estacionales en la riqueza y abundancia total, pero un notable cambio en la composicion de especies entre la primavera-verano y el otono-invierno. El cambio en la composicion de especies promovio pocas variaciones estaciones en la riqueza y la abundancia total, porque fueron compensadas por la abundancia de las especies que visitan el area en las diferentes estaciones. A nivel de las especies, las aves residentes y migrantes de corta distancia tendieron a comenzar la reproduccion antes que las migrantes de larga distancia, y las aves comenzaron la muda de plumas del cuerpo y del ala al finalizar la reproduccion. Por lo cual encontramos una baja superposicion de estas dos demandantes actividades. Nuestros resultados remarcan la importancia del movimiento de las aves en respuesta a las variaciones en la disponibilidad de recursos, que promueven la migracion o el desplazamiento local de las aves.

ecology↗