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.

in pine or mixed forests. Different warbler species occur and feed in different habi­ tats. The same is true o f thrushes. In marsh and tund ra habitats the birds are more clearly separated spatially, because species-specific m icrohabitats are usually found in different places. The birds o f different families usually utilise different foraging strategies. It allows them to avoid competition and to co-habit in the same habitats, in the same forest layer, at the same height and even in the same parts o f crowns. Therefore, variation in spatial distribution is usually feebly marked between the birds that use different foraging strategies. For example, warblers, flycatchers and tits may feed together in the crown o f the same tree. They do not hamper each o th e r’s foraging. Warblers collect prey items from the foliage, flycatchers wait for active prey and capture it in the air or from the surface o f plants, and tits extract invertebrates from bark cracks, twisted leaves, inflorescences and other hides (Marochkina & Cheltsov 2005, Khlebosolov et al. 2006b). Thus, passerine communities are formed o f species which are found in the ecosystems o f Pasvik m icrohabitats o f suitable structure that fit the specific features o f their foraging behaviour. In relation to the foraging strategy and tactics, and to the position of the preferred m icrohabitats, the birds may occur together or sepa­ rately in the different parts o f tree and bush crowns, on different plants, in different habitats or landscape types. 163