To the ecology and biology of closely related species of thrushes of the genus Turdus in different landscapes of northeastern Ukraine

Abstract

Systematic observations of the avifauna of the Pine park in in the city Lohvytsia, the outskirts of the village Potoky and in the «Vakalivshchyna» tract allow to conclude that song thrushes and blackbirds are quite numerous birds, due to the large number of biotopes suitable for their nesting. 37 cases of nesting of Turdus merula and 30 cases of Turdus philomelos were noted. The nesting density of the song thrush in the Pine park of Lokhvytsia is set at 0,36 pairs/km2. In the vicinity of the village The flow rate was 0,96 pairs/km2, in the Vakalivshchyna tract it was 2,5 pairs/km2. For the blackbird, the nesting density in Pine park was 0,36 pairs/km2, the vicinity of the village Potoky – 0,46 pairs/km2 and in oak tracts – 1,5 pairs/km2. In various landscapes of northeastern Ukraine, the nesting period of songbirds and blackbirds extends from April to June. In the Poltava region, the singing thrush arrives days earlier than in the Sumy region. We tend to believe that this is related to the adaptation of the species to the environment in the conditions of urban tree plantations. In different landscapes of the north-east of Ukraine, the construction of nests by Turdus philomelos begins in the first ten days of April (04.01−10.04) at the daytime temperature of +8.5±1.5 °C. Turdus merula builds nests in the first ten days of April (01.04−10.04) in various landscapes of the north-east of Ukraine at an average daily temperature of +5.0±1.0 °С. When different species of blackbirds live together (in the same conditions), species-specific features are most clearly manifested in the distribution of nests by species of trees and bushes, the nature of the location of nests and the height of their placement. The list of species of trees and bushes on which nests of Turdus philomelos and Turdus merula are placed includes 8 plant species. Turdus philomelos prefers nesting sites for Acer negundo (66.6%) in the vicinity of the village Potoky, Ulmus minor (55.5%) and Acer negundo (44.5%) in the Pine Park, Quercus robur (50%) and Ulmus minor (50%) in the Vakalivshchyna tract. Both types of blackbirds are characterized by individual variability in the choice of nest locations. This is most clearly manifested in the atypical location of the nests in the artificial nests (without the top cover and front wall).