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.

Thus, difference in foraging behaviour and use o f different parts o f tree and bush crowns allow Willow Warblers and Common Redpolls to occupy different e co ­ logical niches, avoid competition and co-exist in similar habitats. 3 .1 .4 . Spotted and Pied Flycatchers Flycatchers belong to the ecological groups o f avian “watchers-pursuers” o f invertebrates (Preobrazhenskaya 1998). Their main strategy o f foraging behaviour is that they watch for prey from a perch and grab it by a short flight from the foliage, from the ground, or from the air. In Pasvik flycatchers inhabit different types o f pine, birch, and mixed forest and forage in the crowns and und e r them. Habitat use o f flycatchers is defined by the distribution o f the species-specific feeding sub­ strates, or microhabitats. They select for foraging trees with a certain crown arch i­ tectonics. Pied Flycatchers usually forage in pines whose crown has many open spaces between the horizontal branches. They mainly feed in the middle and lower inner parts of pine crowns (Fig. 3.15). When feeding in birches, Pied Flycatchers mainly hover over the peripheral leaves. They seldom feed in the inner parts o f birch crowns, as there many branches growing at a large angle to the g round are avialable. Foraging behaviour o f Pied Flycatchers is characterised by using relatively short flights to substrate in varying directions mainly within tree crowns. After look­ ing for prey, a Pied Flycatcher usually takes off upwards or downwards and picks the prey from the trunk o f from the foliage. After a pick the bird usually does not return to its perch but rather sits on a branch located below or above it ( “take-o ff —pick - landing” manoeuvre, Fig. 3.16). Flycatching behaviour occurs less often, the Figure 3.15. Habitat structure o f Pied and Spotted Flycatchers in the forest ecosystems o f Pasvik. Arrows show areas where the birds forage. 132