Long-term observation of the egg and chick size in the nests of Larus ichthyaetus in Lake Chany,West Siberia, Russia

Data on long-term observation and morphological study of the eggs of the great black-headed gull Larus ichthyaetus in the nesting colonies of gulls on islands of Lake Chany, RussiaData on long-term observation and morphological study of the eggs of the great black-headed gull Larus ichthyaetus in the nesting colonies of gulls on islands of Lake Chany, Russia

Abstract 

This data set describes the long-term observation and morphological study of the eggs of the great black-headed gull Larus ichthyaetus in the gull nesting colonies on the islands of Lake Chany. Lake Chany is located in the Baraba forest-steppe of the West Siberian Plain, Russia, between the Ob and Irtish rivers (54°30'– 55°09' N, 76°48'–78°12' E). The Lake Chany Basin is among the largest in Russia, and the lake itself has the greatest water surface in West Siberia. The waters, coastal zones, and islands of Lake Chany are favorable for breeding, molting, and feeding of more than 280 species of birds. In spring and autumn, numerous migratory waterbirds (over 300 thousand), such as swans, geese, ducks, coots, waders, gulls, terns, cranes, stop at the lake during migration. Some of the species are rare and endangered and are listed in the Red Data Book of Russia and the Red List of the International Union for Conservation of Nature and Natural Resources (IUCN). Lake Chany is protected by the Ramsar Convention on the Wetlands of International Importance, indicating that the lake is an important site for migratory birds, including L. ichthyaetus. Therefore, it is important to observe the dynamics of their reproduction. Inter-annual changes in the onset of egg-laying and morphological parameters of eggs were pronounced and were probably determined by the course of spring and feeding conditions. Some authors suggest a relationship between the morphological characteristics of eggs and the diversity and survival rate of chicks hatching from them. This dataset contains the size and fate of all eggs, as well as the size of birthed chicks in 1164 observed L. ichthyaetus nests from 1993 to 2003. The number of gull nests varied from year to year. Currently, most of the great black-headed gull colonies are in a vulnerable state; therefore, this species is recorded in the Red Data Books of the Russian Federation and Kazakhstan.