Trophic relationships of birds in forest plantings of the Azov region (Ukraine)

Abstract

The elements of the trophic structure of birds in the Ukrainian Azov region include: availability of food resource s in hab i tats, feeding behavior and foraging methods, and specialization or euryphagous feeding patterns of certain species. Green plants form the basis of trophic relationships, but feeding schemes are much more complex and include animal organisms as well . The trophic relationships of birds in shelterbelts were conducted research during 2019 – 2021 . Adjacent biocenoses, pr i marily agricultural lands, also serve as feeding sites. We analyzed trophic relationships within the framework of research on consortional relationships between birds and dominant tree sp ecies in shelterbelts: Robinia pseudoacacia , Elaeagnus argentea , and Fraxinus excelsior . During the study period, 1–4 bird species fed on Elaeagnus argen tea on diff erent days of the breeding period, and the correlation between the number of bird species and the number of trees on which birds fed was very weak. On Robinia pseudoacacia trees, 1–6 species fed, but this relationship also proved to be very weak. A significant correlation was found for Fraxinus excelsior ; however, the functioning of this trophic consortium was sustained by an average of only 1.8 0 ± 0.33 (1–4) bird species. In the shelterbelts of the study region, 62 breeding species were identified and classified by dominant food sources into the following groups: entomophages – 25 species – birds whose food resources consisted of insects and arachnids; phytophages – 15 species – birds feeding on seeds, grain, fruits, and green plant organs; myophages – 9 species – birds feeding on mouse-like rodents and small mammals; pantophages – 8 species – birds feeding on various foods; and ic h thyophages – 5 species – feeding on fish and small aquatic animals. According to foraging methods, the following categories of birds were identified: birds that perch on tree trunks, mov e along them, and extract insects and their larvae from under tree bark; birds feeding on insects and fruits on thin branches or leaves; predatory birds that capture small birds and insects on branches; birds that collect food primarily on the foliage of trees and shrubs; birds that peck food (insects, seeds) from the ground and search for it in the litter; predatory birds that catch their prey on the ground; species that find food (insects, seeds, grain) in open landscapes (agricultural lands, steppe, meadows, clearings, etc.); and birds that capture food in flight. In our research, we identified a trend of increase or decrease of certain bird groups in shelterbelts of different age. Thus, the number of entomophages in creased from 20.0% (of the total number of breeding species in the studied shelterbelts) in young shelterbelts to 53.1% in old shelterbelts; the number of phytophages decreased with shelterbelt age (from 53.3% to 18.8%); and the my o phage assemblage gradually increased depending on shelterbelt age (from 14.5% to 20.9%). Given the complexity of bioceno t ic relationships, we consider promising areas of research to include studying the relationship between the feeding patterns of avian populations in shelterbelts and a complex of factors: proximity to water bodies, shelterbelt structure, maturity and stabil i ty of plant ing s, and plant cover diversity. Also, in the context of trophic activity of birds, the phenomenon of zoochory is e x tremely interesting – the transport of plant propagules by animals, particularly birds, in various ways. By consuming plant seeds and fruits, birds leave undigested food remains in various locations, where over time we observed the emergence of vegetation patches.