Launching an application of the radiotelemetry method, we endeavour to determine the home range size of Capercaillies and forest structure characteristics in terms of the age and tree species composition; forest site moisture and species composition of the herbal layer preferred by capercaillies in their habitats. We conduct our investigations in the mixed coniferous forest of the northern Belarus. This area is distinguished by apparent abundance of capercaillie. Five radio-marked males of adult capercaillie Tetrao urogallus were tracked in the period from April 2010 to November 2011 (in total 206 locations of all males). The first obtained data show that the home range size of the longest radio-tracked male reaches 2 810.93 ha (the number of fixes n = 141). The range span, that was considered as a distance between two farthest points including a distance to the lek where male has been captured, is 7,877 m in the period from April 2010 to November 2011. Home ranges and range span of other four males during period from 16^th May to 30^th November 2011 were as follows: 1,278.6 ha (7,844 m); 206.5 ha (2,633 m); 149.4 ha (2,615 m) and 90.9 ha (1,296 m). During the whole radio tracking period, capercaillies mostly occur in the mature mixed pine and spruce and spruce and soft deciduous stands growing in the dry forest sites and in the pine stands in the overmoistured and peatland sites. All males select locations with bilberry cover in the mature forests. The longest radio-tracked male shows the largest dynamics of the home range in September and March while the least was in May – July and December – January. The single case of autumnal singing has been registered. Considering the annual natural cycles through the year, foraging habits and lifecycles of capercaillie, we have distinguished nine stages of lifecycles in the adult males of capercaillie as the ground for the further investigations.

Keywords: capercaillie, radiotelemetry, home range, range span, habitat, autumnal singing.