Pierwsze stwierdzenie lęgu mieszanego mewy srebrzystej Larus argentatus i mewy białogłowej Larus cachinnans na Śląsku 1 The first record of hybrid breeding in Herring Gull Larus argentatus and Caspian Gull Larus cachinnans in Silesia

Paweł Kołodziejczyk, Jakub Szymczak
On 13.05.2006 on Paczkowski reservoir (Upper Silesia voivodship) we did first record of mixed brood of female Herring Gull Larus argentatus with male Caspian Gull Larus cachinnans in Silesia. In nest we found 3 eggs. Parents were observed again on 21 and 27.05 and at the same time 3 small nestlings were spotted in nest. Herring Gull was banded and thanks to that it was known that she was ringed on 19.05.2001 in Tarnów (Małopolskie voivodship) as small chick (wing length 40 mm) in Caspian Gulls
more » ... reeding colony. After consultation of diagnostic features, photography, and biometrics was stated that bird is Herring Gull. Record of mixed brood on Paczkowski reservoir and in Tarnów are in present most south breeding localities of Herring Gull in Poland.