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Bird migration is usually performed in several consecutive flights, interrupted by stopovers when birds rest or replenish their fuel loads. As a result, migrants must decide when and where to land. Here, we studied the effects of meteorological conditions (wind and rain) and age (used here as a indicator of bird experience) on the probabilities of sedge warblers Acrocephalus schoenobaenus landing at a stopover site in northern Iberia. Data were collected over three consecutive years at a ringing station during the autumn migration period. We used reverse-time capture-mark-recapture models to estimate seniority, ? (i.e., the probability that an individual at time t was already present in the population at time t - 1), as an indicator of landing decisions, since 1- ? represents the probability of recording new individuals (i.e. recent landings). We ran 14 models with the above mentioned variables, four of which were best supported by the data. In these, only rain showed a significant positive effect on ?, indicating that birds of any age class avoid flying during rainfall and prefer to interrupt their migration. These results are similar to those obtained from an analysis of day-to-day variation in first captures that was used to validate the usefulness of capture-mark-recapture models. They suggest that CMR models can serve to study bird landing decisions during migration in some specific cases.

Andueza, M., Barba, E., Arizaga, J. 2014. Using capture-mark-recapture models to assess the effect of age and weather on landing decisions of Sedge Warblers (Acrocephalus schoenobaenus) during migration. Ardeola 61(2): 269-283. https://doi.org/10.13157/arla.61.2.2014.269.

Ornitología