Seasonal nutrition variability and trophic differentiation of ducks on Baikal

Abstract

The analysis of the food ration of 7 species of ducks from Lake Baikal helped to reveal the features of the seasonal dynamics of ducks feeding. The degree of trophic differentiation was determined for all species and for systematically related forms. All species of ducks in general are polyphages of different ranges, there are no highly specialized species. According to the ratio of plant and animal feed, three trophic groups were identified among ducks: phytophages, mainly phytophages and zoo-phytophages. Ducks plant feed is represented by seeds, vegetative parts and tubers. At the same time, a significant proportion are seeds, especially sedge, which in some species of ducks (Anas platyrhynchos, Anas penelopе, Anas acuta) in some seasons exceed 1520% by volume in the stomach and esophagus. Anas querquedula and Anas clypeata ignore vegetative parts of plants, while mallard consumes them only in summer. Anas penelope selects vegetatic parts of plants and seeds, in spring they are selected by Anas acuta. Animal feed is actively consumed by Anas crecca, Anas querquedula, Anas clypeata, Aythya ferina. It is noted that Anas clypeata consumes mollusks in large numbers, while Aythya fuligula consumes them to a slightly lesser extent. Anas querquedula and Anas clypeata prefer insect larvae. Gammarids are quite common for most species of ducks and in volume they occupy a worthy place. Seasonal nutrition dynamics are well traced for all types of ducks. Ducks prefer to use accessible objects, while showing species selectivity in the choice of feed components and feed biotopes. As a result, we see a low overlap of trophic niches of various types of ducks, including systematically close forms.