Nature Conservation Research: Заповедная наука (Aug 2016)
The spring migration of waterfowl in the Reserve Olekminsky
Abstract
The species composition of waterfowl that pass through Olekminsky Reserve is represented by 24 species; 9 of them are transient birds. Other species are presented as transient as well as nesting. Widespread species are bean goose, whooper swan, mallard, pintail, teal and tufted duck. The uneven distribution of wetlands and their limited variety determine the presence of only two places where there is a pronounced transition and regular stops of migrants. These are the lake-wetland complexes in the Olekma river valley and, to a lesser degree, the head of the Tuolba river. The total number of waterfowl transiting through the territory of the reserve during seasonal migrations has been estimated at 10000–20000 individuals. However, the wetlands nature reserve attracts, as a place of rest and foraging, an average of only 5% of the migrants. Dynamics and time of bird transition were almost the same as in the area of the Lena-Amga interfluve and relevant sections of the river valley Lena. Some differences can be traced in abundance of some species. The span whooper swan, e.g., accounted for up to 4.5–5.5 thousands individuals per season. Long-term dynamics of the migratory population of several species of geese, swans and ducks have opposite tendencies (the apparent rise, cyclical fluctuations, the decline). However, the total number of waterfowl migrating through the territory of reserve «Olekminsky» tends to decrease, which can be concluded at the observation data of the spring migration.
