Egg and Chick Size in the Nests of Common Gulls in Lake Chany, West Siberia, Russia From 1993 to 2011

ABSTRACT A long‐term study of the breeding ecology of different gull species has been conducted 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 Wetlands of International Importance, indicating that it is an important site for migrating and breeding birds, including the Russian common gull ( Larus canus heinei ). We observed the colony of common gulls during the breeding season from May to July, 1993 to 2011, and searched a total of 4188 nests. We recorded clutch size and eggshell coloration, and measured egg length and width. Moreover, we recorded the fate and hatching date of individual eggs and determined the clutch initiation date. Head, bill, tarsus length, and body weight of newly hatched chicks were measured. A total of 8289 eggs and 3865 chicks were measured. The presented data can be used for comparison with other local results to assess how environmental changes caused by human activity, including global warming, affect the reproduction of migratory birds. This is a novel long‐term dataset on a population of this species in central Eurasia. The Metadata for this abstract is available in MetaCat in JaLTER at https://doi.org/10.20783/DIAS.JLE.98 , and the complete dataset is available at https://zenodo.org/records/12038421 .