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.

Willow Warblers more frequently occur in birch stands, whereas Bramblings prefer well developed pine and mixed forests (Fig. 3.1). The composition o f forest vegeta­ tion in Pasvik is rather uniform. The diversity o f plant comm u n itie s is increased by differences in age, growth conditions and relative numbers o f the two dominating tree species: pine and birch. We marked out nine types o f pine and birch forests that have different veg­ etation structure and thus non-identical density o f Willow Warblers and Bramblings (Khlebosolov et al. 2000). Willow Warbler. The numbers o f Willow Warblers are governed by the o c c u r­ rence o fb irch trees in the stands (Lapshin 1990, Zimin et al. 1993). The maximum population density is recorded in pure all-aged birch forests (Fig. 3.1, types 1—3). In Pasvik, birch forests mainly grow in river valleys and lake galleries. At the early A.R. Duasbaev The Willow Warbler is one o f the most com mon forest passerines in Pasvik. 10 cd CL <D О C<D 5-4 3 О О О Figure 3.1. Occurrence o f Willow Warbler and Brambling in different types o f forest in Pasvik N ature Reserve (Russia). 1 - sem ifrutex and lichen birch forest; 2 - riparian birch forest; 3 - red bilberry and grass birch forest; 4 - yernik and peat pine forest; 5 - green moss and sem i­ frutex mixed pine and birch forest; 6 - lichen-m oss-sem ifrutex pine forest; 7 - lichen pine for­ est; 8 - red bilberry pine forest; 9 - peat and sem ifrutex pine forest. -■— Willow Warbler ... Brambling 118