title: Influences of wind flow on stopover decisions: the case of the reed warbler Acrocephalus scirpaceus in the Western Mediterranean.
abstract: Wind directions measured at two different heights (850 hPa and 700 hPa) and at different hours of the night were analysed during the spring migration passage at a bird stopover site located in the western Mediterranean, in order to evaluate the importance of wind components for a stopover decision. From a huge ringing campaign of bird migration in north-east Spain, data from the reed warbler Acrocephalus scirpaceus have been used for the analysis. From a total of 2,478 reed warblers captured between 1993 and 1997 data recording significant days, with a high number of captures, and decrease days, with few captures, have been selected to develop an analysis of wind direction in relation to stopover and flight resumption. On days with a high capture the winds had mainly a fourth-quadrant flow (from the north, north-west and west), these being mainly head winds. Winds with westerly component (from the north-west, west and south-west), which enhance the flight, account for the majority of the days when there was a low capture of reed warblers. Wind direction therefore appears to be a determining factor for stopover decisions and resumption of flight for the reed warblers at an intermediate stage of their spring migration where topographical characteristics govern the winds.
authors.affiliation: Departamento de Geografia Física, Facultad de Geografia, Universidad de Barcelona, Spain. barrioca@wanadoo.es
authors.forename: C
authors.initials: C
authors.lastname: Barriocanal
authors.forename: D
authors.initials: D
authors.lastname: Montserrat
authors.forename: D
authors.initials: D
authors.lastname: Robson
mesh_terms: D000818:Animals; D005426:Flight, Animal; D019083:Mediterranean Region; D012621:Seasons; D020308:Songbirds / Q000502:physiology*; D014919:Wind