Spring migration of Sylvia species over the southernmost point of Europe Gavdos Island (Crete, Greece)

Abstract

The island of Gavdos, situated only 250 km north of the African coast, is the first land birds reach flying across a long stretch of the open sea in spring and acts both as a refuelling as well as an emergency landing site for northward bound migrants. We report here patterns of the spring migration of the genus Sylvia trapped on Gavdos in mist-netting surveys conducted in three successive springs in the period 2002-2004, and in 2022. Out of a total of 7983 individuals of 17 genera and 74 species ringed across the four years, there were 2211 individuals of eight Sylvia species, making up to 30.7% of the total catch per season. S. borin was the most commonly trapped species among the nine (S. atricapila, S. borin, S. cantillans, S. communis, S. curruca, S. melanocephala, S. nana, S. rueppelli, S. nisoria), accounting for 62.2% of the total Sylvia catch. The longest mist-netting period covering 75 spring passage days carried out in 2022 in which seven Sylvia species were trapped, including Sylvia melanocephala (N=7) trapped for the first time on Gavdos. Differences were also observed in the phenology of the passage, albeit not for all species. The late onset of the passage is most likely attributable to an unusually cold spring with long periods of strong, opposing north-westerly winds rather than an actual shift in the spring passage timing.