Migration patterns and fat reserves of Curlew Sandpipers Calidris ferruginea at a stopover site in southern Italy

Abstract

The Volturno Plain, southern Italian coast, is a regular stopover site for Curlew Sandpipers during northward migration. During 1992–1998, 2,177 Curlew Sandpipers were ringed and measured on northward migration; numbers trapped each year fluctuated. Peak passage was during the period 6–10 May, with 94% of birds trapped in the period 1–20 May. Median date of passage of males preceded females by about five days. Using a new visual method to evaluate fat deposition in waders, there was a strong correlation between body weight and visually estimated fat deposits. Birds showed a mass increase of 2.8 g/day. The mean stopover duration was 2.2 days. Only 0.9% of the total catch of Curlew Sandpipers were first-year birds. It is possible that the same flocks visit this stopover site annually during northward migration. Ringing recoveries occurred along two main routes and confirmed that most of the Curlew Sandpipers on passage through the Volturno Plain also used stop- over sites in Greece (1,000 km from our study area) and in the Black Sea region (1700 km). On southward migration they followed the East Atlantic Flyway. The flight range was estimated to be 1,000–1,900 km.