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.

around and selects the direction of further movement (Fig. 3.31). Bluethroat. Bluethroat breeding density in opti­ mal habitats reaches 20 pairs • km 2. Its territory size is ca. 3—4 ha. Breeding territories usually have an elon­ gated and awkward shape. Bluethroats cannot forage in typical forest habi­ tats, because the ground layer there is formed by high and dense subshrubs: red bilberry, bilberry, great bil­ berry, black crowberry, crystal tea ledum. Wet herba­ ceous and subshrub habitats limit the field of vision and are unsuitable for Bluethroats. Microhabitats where this species can forage are found under the crowns o f bushes or young trees on the border between forest and bog, and in coastal scrub (Fig. 3.32). In such places umbrageous conditions prevent the growth of herbs so that patches of open ground are available, even though the trunks of bushes and trees somewhat limit visibility and decrease the detection distance of prey. Bluethroat is a ground-feeding bird. It has relatively simple foraging behaviour (Fig. 3.31). A series of quick hops is followed by looking around. If prey is located, the bird picks it immediately after looking around or after 1—3 additional hops. Then the next series of hops and looking around follows. Analysis o f behaviour and ecology o f passerines of coastal scrub shows a clear dif­ ference that allows these birds to co-occur in similar habitats. All the four species of V.N. Savin The Bluethroat is a ground- feeding bird that lives under the bushes and along bog edges. Luscinia svecica Figure 3.32. Structure o f Bluethroat microhabitats in the transition zone between bog and forest. 153