Resumen:
|
[EN] Factors determining departure decisions of migrants from a stopover site can be extrinsic
and/or intrinsic but the relative role of each of these factors on departure decisions is still poorly known.
Date and wind ...[+]
[EN] Factors determining departure decisions of migrants from a stopover site can be extrinsic
and/or intrinsic but the relative role of each of these factors on departure decisions is still poorly known.
Date and wind should be the main factors determining departure decisions in a long-distance migrant,
which is expected to minimise duration of migration. Date was considered as an intrinsic factor and
wind as an extrinsic one. We analysed the capture-recapture data of a long-distance migrant European
songbird, the sedge warbler Acrocephalus schoenobaenus,from a stopover site in northern Iberia during
the autumn migration period to quantify the relative importance of several factors on emigration
likelihood. Cormack-Jolly-Seber (CJS) models were used to estimate the emigration likelihood. from
107 models tested, only the model with an additive effect of date, tailwind assistance and population
size substantially supported the data. As expected, sedge warblers were more likely to depart with
high tailwind values and late in the season and, contrary to expectations, with decreasing sedge
warbler abundance
[-]
[ES] Los factores que determinan la decisión de abandonar un área de descanso durante el periodo de migración pueden ser extrínsecos y/o intrínsecos. En las aves que tienden a reducir el tiempo de la migración, tanto la ...[+]
[ES] Los factores que determinan la decisión de abandonar un área de descanso durante el periodo de migración pueden ser extrínsecos y/o intrínsecos. En las aves que tienden a reducir el tiempo de la migración, tanto la fecha como la meteorología deberían ser los factores principales que determinan las decisiones de partir. Se analizaron datos de captura-recaptura de un migrador transahariano, el carricerín común Acrocephalus schoenobaenus, de un área de descanso en el norte de la península Ibérica durante el periodo de paso posnupcial para cuantificar la importancia relativa de diversos factores en la probabilidad de emigración. La probabilidad de partir se estimó con modelos Cormack-Jolly-Seber (CJS). De 107 modelos, solo uno tenía respaldo suficiente, de acuerdo al criterio AIC. Dicho modelo incluía el efecto aditivo de la fecha, viento y densidad de aves. Como se esperaba, los carricerines comunes tenían más probabilidad de partir con vientos de cola elevados y en fechas más tardías, siendo esta probabilidad más elevada para densidades bajas.
[-]
|
Agradecimientos:
|
We are grateful to the people who collaborated during the field work; especially D. Alonso, X. Esparza, J. Goikoetxea, J. Jauregui, M. Laso, A. Mendiburu, R. Piculo and A. Vilches. The Plaiaundi Ecological Park team (N. ...[+]
We are grateful to the people who collaborated during the field work; especially D. Alonso, X. Esparza, J. Goikoetxea, J. Jauregui, M. Laso, A. Mendiburu, R. Piculo and A. Vilches. The Plaiaundi Ecological Park team (N. Aizpurua, M. Etxaniz, A. Luengo) provided us with facilities to work at Jaizubia. This research was funded by the Basque Government, Gipuzkoa Administration, Orona and Kutxa, as well as by the Spanish Ministry of Education (pre-doctoral fellowship to MA) and the Spanish Ministry of Science and Innovation (project CGL2010-21933-C02-02). Two anonymous referees provided very valuable comments that helped us to improve an earlier version of this work.
[-]
|