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.

Figure 2.2. Main ecological groups of birds of Pasvik. groups that inhabit different habitats: (1) forest birds; (2) birds o f coastal scrub and swamps; (3) mountain tundra birds (Fig. 2.2). For o th e r ecological and taxonom ic groups o f birds a brief comparative characteristic o f th e ir behav iou r and ecology is given, and possible mechanisms o f ecological segregation are discussed that allow their co-existence (or separate existence) in various landscapes. 2 .4 . Characteristics of the main ecological groups of birds 2 .4 .1 . Waterfowl Waterfowl play an important role in the natural ecosystem s o f Pasvik. A large proportion o f the area is occupied by rivers, stream s, lakes, w etlands, sea coast. It provides favourable conditions for waterfowl th a t is rep resen ted by a large num ber o f species and causes a high population density (F ran tz en et al. 1991; Bianchi et al. 1993; Wikan et al. 1994; Thingstad et al. 1997, Annals o f N a tu re ... 1997, 1998; Bianchi 1999). Below we review the peculiarities o f spatial d istribu tion , diet, forag­ ing behaviour and the possible m echanism s o f ecological segregation in waterfowl in the wetland ecosystems o f Pasvil. Divers In Pasvik two species o f divers breed, the R ed -th ro a ted D iver and the Black- throated Diver. Both species feed almost exclusively on fish which they catch by long diving. Both species are clearly spatially separated. R ed -th ro ated Divers breed on small eutrophic forest lakes or on swamp lakes. The nest may be located on a fish-free water body, whereas adults forage and collect food for nestlings in a n ea r­ by river or lake. B lack-throated Divers, conversely, prefer to breed in the Pasvik 78