Influence of seasonal climatic factors on the dynamics of birds interactions with linden consortia

The article is devoted to the bird communities in individual linden consortia (Tilia cordata Mill.) of the linden-ash oak forests. This work material was collected during different seasons of the 2009–2017 years in a linden-ash oak grove on the test plot No. 209 of the ecological profile of the NSC «Bel'gard Prisamar`e International Biospheric stationary», Novomoskovsk district, Dnepropetrovsk region. The individual consortia of 145 examples of three age conditions oak trees (virgins – virg, young generative – gl, mature and old generative individuals – g2-g3) has been investigated. Studies have shown that birds are actively involved in consortia of linden for most of the year. Meroconsortia of linden generative organs are attractive to birds during the growing season and in the cold season. In summer, the consortia of linden in terms of species composition of birds is inferior to the consortia of oak about 2 times. The same trend is observed in DTB and DMB. Only 2 species of birds participate in the consortia of the virgin linden. The consortia of young generative linden consists of only 4 species of birds, but DTB increases almost 30 times. The consortia of mature and old generative linden acquires a sufficient species composition – 14 species of birds. Interactions of birds with virginal linden are stochastic in autumn. Only 2 species of birds participate in the consortia of virgin linden in autumn. The consortia of young generative linden consists of 5 species (more than in summer). The old generative linden has a depression of consortia interactions of birds. Their volume is reduced by half compared to summer. Specialized consumers of linden nuts remain in the consortia of old generative linden mainly. Birds have very low DTB and DMB rates in consortia of all linden age groups in winter. Instead, the species composition of birds increases in the consortia of generative groups of linden in winter. The system of consortia interactions of birds is not intensive, but stable on the linden tree in winter. The volume of interactions of birds with a linden tree essentially increases in the spring. This trend is typical for trees with a dense crown. The number of consort birds is higher than in summer in consortia of virgin and young generative linden. DTB is five times higher in virgin linden than in summer. The participation of birds in the consortia of young generative linden is also greater than in summer. We believe that this is due to the fact that linden begins to grow earlier than other trees in the upper tier. The old generative linden is one of the main feeding grounds for birds in the spring. Linden, like common oak, is much more interesting for birds in spring and summer in contrast to field maple and ash. Linden first supports the system of trophic connections, and then topical in most seasons of the year. Linden forms stable groups of birds at a young generative stage during the year. Linden creates an environment for birds to live in the middle tier and complements the field maple.