Nesting of fieldfare Turdus pilaris (Linnaeus, 1758) (Aves, Passeriformes) in floodplain habitats of the Abakan River basin (South Minusinsk basin)

This paper presents the results of long-term observations of the fieldfare breeding biology in the South Minusinsk basin. The observations were carried out at two sites in floodplain habitats of the Abakan River basin. Comparisons were made with the indicators of the breeding biology of the species in the North-Minusinsk basin, which were published. The fieldfare builds nests on all kinds of woody plants that are found in the floodplain. The time of Turdus pilaris reproduction beginning in the steppe basin varied from the 20th of April to the first five days of May. Differences in the breeding periods of fieldfare in populations from different altitude-belt complexes (steppe and forest-steppe) were revealed. There is a difference in the height of nests on woody plants, depending on the architectonics of the crown, and in areas with varying degrees of concern. Dimensional characteristics of nests and eggs are given. High intrapopulation variability of egg size was noted. The coefficient of variation for the larger and for the smaller diameter was 11–13%. The full clutch consisted of 4–6 eggs. The average clutch size was 4,9–5,2 eggs. Differences in the average size of the masonry on different territories were not revealed. The success rate of nesting in 2021 was high (50–72%).