The seasonal placement of the Caspian Gull Larus cachinnans from the Northern-Western Coast of the Azov Sea based on Ringing Results

Dubinina Y.Y.

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Abstract:

Connections between nesting areas of the Caspian Gull Larus cachinnans in the Northwest coast of the Azov Sea and the rest of Europe were examined by a long-term ringing program (1988–2012). The author analyzed the spatial distribution of individuals according to age (young, immature, adults) during different seasons. Directions and flight distances were determined and different types of dispersal (intra-continental, within the territory of Ukraine, within the nesting area) were specified. For perennial large nesting settlements of the Caspian gulls in the Northwest coast of the Azov Sea, the following features were determined: high degree of phylopatry in adults, the wide scope of migration after nesting and dispersion of young birds, formation of new temporary colonies by virtue of immature birds. The average movement of birds towards their colonies, during the spring was 1033 km (range 111-1900). During the post-nesting season, adult birds were found within a radius of 30 km around their colonies. In June the average displacement distance of birds of different age groups, from their colonies was 130.14 km (range 7.5-1900). In July and August, increased to 416.17 km (range 7.5-2025). In autumn, birds were found within an average distance of 284 km (range 7.5–2025) from their natal area, moving along the coast, mainly in a southwestern and western direction. They were also present in large numbers in landfills and agricultural land. Some first year birds reached the territories of Denmark, Germany, Poland and Hungary. In winter, the average displacement distance was 850 km (range 7.5-2172). The birds usually moved along the Black Sea coast of Ukraine flying to the territories of Eastern European countries.