A change in spring arrival dates of gulls to lake Baikal

In the recent decades of years, dates of spring arrival of Mongolian Gull Larus (cachinnans) mongolicus Suschkin to Lake Baikal were moved to c. two weeks earlier. Similar tendency is recorded in Common Gull L. canus and Black-headed Gull L. ridibundus, but seems to be not applicable to Little Gull L. minutus. It is definitely not connected with a variation of ice melting dates at Lake Baikal and is probably affected with climatic changes at breeding grounds or migratory routes.