Scientific publications

In the wide sense the term ‘biodiversity’ covers all displays of the life variability, and its ethological constituent is as important in sustaining of population stability as others. We investigated the behaviour of Leaf Warblers, genus Phylloscopus (Boie, 1826), at northern peripheral parts of their ranges (Karelia, Russia) in comparison with the conspecifics from central parts of the ranges (published data) and found out that plasticity of territorial systems and variety of behavioural reactions along with other adaptations allow them obtain the populations even in not optimal conditions. This is relevant to relationships within and between species: (1) variety of territorial patterns of conspecifics lets them inhabit quite different sites in the vast ranges, and (2) behavioral variations among different species give them a possibility to settle at the same place. So, comparing conspecifics from central parts of ranges, Willow Warblers Ph. trochilus acredula (Linnaeus, 1758) and Chiffchaffs Ph. collybita collybita (Vieillot, 1817) in Karelia have a shorter prebreeding period, less aggressive ways of territorial borders establishing and lack of some stages of stereotype pair formation. Such reduction of territoriality is mainly caused by the deficit of time good for breeding and relatively low population densities in northern regions. Concerning interspecific variations, Willow Warblers and Chiffchaffs (common species for the region which they have been settling for evolutionary long time) form high stable territorial structures, while Wood Warblers Ph. sibilatrix (Bechstein, 1793) and Greenish Warblers Ph. trochiloides viridanus (Вlуth, 1843) (settled here comparatively later) have more labile territorial structures that let them more actively move during a breeding season in search of potential reproductive partners. Besides, the behaviour of Leaf Warblers also varied depending on the level of social tension in populations, habitat structure and volume of sites suitable for nesting and foraging.