The state of Recurvirostra avosetta Linnaeus, 1758 and Larus ichthyaetus Pallas, 1773 (Aves, Charadriiformes) populations of the Tryochozyorki tract (South Minusinsk basin) in 2020

Abstract

This paper presents the results of observations on the state of two bird species populations listed in the Red Book of the Russian Federation Recurvirostra avosetta L., Larus ichthyaetus Pall. The populations of these species in the State Natural Reserve Tryochozyorki Tract have been studied by the authors for 8 years. The wetland is a key ornithological area of international importance. The paper presents information obtained in 2020, which has been compared with the information received in 20132018 which was published. For R. avosetta L. the maximum number of breeding pairs (127) and the maximum value of the average clutch size (3,6) were noted for the entire observation period. The reproduction of R. avosetta L. started earlier than in previous years. For L. ichthyaetus L. a relatively high number (no less than 280300 pairs) and also the maximum value of the clutch size (3,0) were noted, the breeding time of the species turned out to be typical for this territory. The analysis showed a favorable state of the populations of these species. The previously stated assumption about the relationship of the studied indicators of the nesting biology of these species with the level of water content of the territory was further confirmed.