Migration and wintering of Blackcaps Sylvia atricapilla in Eastern Spain

To describe the phenology of migratory passages and wintering of Blackcaps.Location: Orange plantations in eastern Spain.Methods: Data were collected between 1997 and 2002 at a Constant Effort Site. Results: We captured between 94 and 206 individuals per season (from September to April of the next year). We used information on seasonal variation of fat score and the distribution of intra-seasonal recaptures to distinguish between the postnuptial passage (from late September to mid October), the prenuptial passage (from early to late April), and the wintering period (from mid October to late March). More juveniles than adults were captured both during the migratory passages and during the winter. A similar proportion of males and females were captured during both passages, while males were more abundant during most of the wintering period. We found no differences in dates of passage between age classes or sexes.Conclusions: We described for the first time in Spain the phenology of both post- and prenuptial migratory passages and wintering of Blackcaps at a particular site during several years. Data presented here, along with other published studies, suggest the existence of differential migration between sexes. Females might winter at lower latitudes than males.

Arantza Leal, Juan S. Monros & Emilio Barba, Ardeola 51(2), 2004, 345-355