Do subspecies of bluethroat Luscinia svecica show a geographic segregation during the autumn migration period in Spain?
Published: Volume 53(2), December 2006. Pages 285-291.
Original Title: ¿Muestra el pechiazul Luscinia svecica en España una segregación geográfica en el paso postnupcial a nivel de subespecie?
Aims: Data on proportions of subspecies of bluethroat in different localities in Spain were analysed, in order to know if there is a geographic segregation during the autumn migration period.
Location: Bluethroats were caught at nine Ringing Stations in the North of Spain (Cantabrian: Fuenterrabía, Gautegiz-Arteaga, Villaviciosa, Ponteceso and Ribeira; Villafranca and Castronuño in the Ebro and Duero Basin, respectively), Central Spain (San Martín de la Vega) and the Southeastern Spain (Elche).
Methods: In order to distinguish the subspecies, the age and sex of each bird were determined and its wing length recorded. Thereafter, data on proportions were analysed with c2-based tests.
Results: Two subspecies were registered (L. s. cyanecula and L. s. namnetum), occurring they both at all the sampling localities, though proportions significantly varied. L. s. svecica only appeared in SE Spain, and in low proportions, supporting that this subspecies in Spain is an accidental bird (even in SE most, if not all individuals may have been classified by error as L. s. svecica). Highest proportion of L. s. namnetum were registered along Cantabrian coast (on average, more than 70 %), followed by Duero (almost 20 %) and the Ebro basins, C and SE Spain (on average, less than 5 %).
Conclusions: Data support a geographic segregation of L. s. namnetum and L. s. cyanecula in Spain, during the autumn migration period. L. s. namnetum migrates mainly along northern coast of Spain (though deviating some specimens to Duero basin). Contrary, L. s. cyanecula seems to be a broad front migrant.