The birds of Pasvik / E. I. Khlebosolov, O. A. Makarova, O. A. Khlebosolova [et al. ; English transl. Nikita Chernetsov]. - Ryazan : Golosgubernii, 2007. - 175 с. : ил., портр.

A.M. Khokhlov The Pasvik River forms many bays and calm stretches where different species of waterfowl occur. river or in large valley lakes. The mechanisms o f resource sharing and niche sepa­ ration between these two species remain unknown (Semenov-Tian-Shansky & Gilyazov 1991, Zakoldaeva 2005, Ivanter 2006). Swans The Whooper Swan regularly occurs in the Pasvik valley on large lakes and large swamps. Whooper Swans feed on both plant and animal food. They eat rhi­ zomes and green parts o f plants and small aquatic invertebrates. In spring and in autumn swans mainly feed on aquatic plants, e.g. on lake quillwort (Isoetes lacus- tris), swamp horsetail (Equisetum fluviatilis ), mare's tail ( Hippuris vulgaris ), water milfoil (Myriophyllum altemiflorum) , pond water-crowfoot ( Batrachium peltatum ), awlwort (Subularia aquatica). In summer, they feed not only on the water but also on dry soil. Their diet includes filamentous algae, sedge leaves and cloudberries. Whooper Swans mainly remain in relatively shallow waters. They take food from the bottom by dabbling (Kolosov et al. 1975, Semenov-Tian-Shansky & Gilyazov 1991). Geese Geese are less aquatic than other waterfowl. They walk and run well, feed mainly on the ground on plant food, biting the softest parts off coastal or terrestri­ al plants. 79