Egg and chick size in the nests of common gulls in Lake Chany, West Siberia, Russia from 1993 to 2011

A long-term study of breeding ecology of gulls has been carried in the area of Lake Chany. Lake Chany is located in the Baraba forest-steppe of the West Siberian Plain, Russia, between the Ob and Irtysh rivers. The Lake is protected by the Ramsar Convention on the Wetlands of International Importance, indicating that the lake is an important site for migrating and breeding birds, including the Common gull Larus canus (Linnaeus, 1758). We provided data on the size and fate of all eggs as well as the size of hatched chicks in Common gull nests from 1993 to 2011. The data can be used to assess how environmental changes caused by human activity, including global warming, affect the reproduction and population dynamics of migratory birds.