Winter bird fauna of the Baikal region: A new approach to the analysis of materials

Baikal Museum of the Siberian Branch of the Russian Academy of Sciences, 1, Academic St., Setl. Listvajnka, Irkutsk Oblast, 664520, Russia

^* Corresponding author: yumel48@mail.ru

Abstract

Based on the materials of long-term studies (1964-2024), modern changes in the composition of the bird fauna of the Baikal region in winter are shown. A clear trend towards a decrease in the abundance of birds over a wide area has been revealed. At the same time, their species composition has increased significantly. It is proved that the main reason for such changes is a strong warming of the climate – 1.9 ° C/100 years. The process of formation of “cold” wintering grounds in new species cannot be explained without a detailed study of their late autumn flight. It is shown that such wintering in birds is forced. Changes in the species composition of birds and their status at this time necessitate the development of a new classification of their winter population. The greatest difficulty in this classification is associated with the analysis of the status of a few wintering birds. The most important point, in this case, is that a small part of such species remains for the winter, and the main part of them moves south. In this regard, two more features have been introduced into the new classification: the abundance of wintering atypical bird species and the frequency or periodicity of their appearance in wintering grounds. Based on this, the allocation of three more categories of wintering birds is justified: forced wintering common species (force. win), forced wintering random or very small species (ac.win) and birds that escaped from cages or aviaries (encl. run). The new classification allows for more precise and detailed identification of different categories of wintering birds. It makes it possible to more correctly track the appearance of “cold” wintering grounds atypical for temperate latitudes in different bird species and explain the reasons for their formation.