L’origine des Goélands pontiques qui nichent en Pologne

The Caspian Gull Larus cachinnans was originally a very eastern bird breeding only on sandy lagoons along the coast and at steppe reservoirs. But its population has increased significantly in the past 100 years, reaching western Ukraine, Poland, and Belarus. During the 1980s, a breeding population was established along the Vistula River, in east-central Poland. En 2005, there were over 500 pairs in Poland, and 850 in 2007! The growth of this population seems to be largely due to immigration from eastern colonies, mainly from Ukraine.
Between 1999 and 2006, about 500 large white-headed gulls were trapped at inland breeding colonies in central and southern Poland, and three ringing recoveries of Caspian Gull were obtained. All three breeding adults were ringed as chicks in Ukraine, confirming the eastern origin of Caspian Gulls breeding in Poland.
Grzegorz Neubauer and Magdalena ZagalskaNeubauer, from the Institute for Ornithology, Polish Academy of Sciences, and Jacek Betleja, from the Department of Natural History, Upper Silesian Museum Institute, allowed us to publish a French version of its note « The origin of ‘Caspian Gulls’ breeding in Poland » published in the September 2007 issue of British Birds.