Long-term monitoring of spring migration time in passerines in the Courish Spit (the Baltic Sea). 2. Influence of temperature on migration terms

摘要

The terms of spring migration were analyzed in 20 migrating Passerines species in relation to mean spring temperatures. The mean terms of migration in 6 species arriving predominantly in April are significantly related to the April temperature: the higher temperature, the earlier are terms of migrating birds through the Courish Spit. A significant negative correlation are found between the terms of migrating and May temperature. The long-term and significant changes in terms of spring migration in birds, especially in Passerines. due to climatic fluctuations in the northern hemisphere were revealed based on published data and the authors' own. The observed increase of the average annual air temperature in the 1930s. 1940s and then in the 60s and the 80s caused a shift in terms of spring migration to the earlier dates. A decrease of the average annual temperature in the 1950s, 1970s. and probably in the 1990s, moved the terms to the later time. The climatic changes were reflected to the terms of spring migration in the species hibernating in Europe and Africa.