Long-term monitoring of spring migration time in passerines in the CourishSpit (the Baltic Sea). I. Dynamics of migration terms

Analysis of spring migration in 33 Passerines species showed that the earli er the species migrated through the Courish Spit, the greater is variation of migration terms. The annual variation of migration terms is not related to a distance of migration. During the period under investigation (1959-199 6), in early (April) migrating birds the early terms of migration were char acteristic of the 1960s and the 1980s, the later migration terms were obser ved in the 1970s and 1990s. In the birds migrating in the later period (May ), only in the 1980s the earlier terms of migration were registered except the latest migrants.