Zizas, Rytis

The aim of the study was to analyse the forest structure in the surrounding of capercaillies microhabitats in two regions of Lithuania and in the Belarus, and to compare the microhabitats of malęs and females. Data about capercaillie microhabitats (birds locations) were collected by direct observation, by radio telemetry and by the ųuestionnaires of foresters. The forest structure parameters in capercaillie locations were described, since tree species composition was very diverse, stands were grouped by distinguishing 10 categories of biotopes. The GIS method ond comparative analysis was used in order to to further examine stand structure in the microhabitats of capercaillies and to compare the habitats used by birds of different sexes. Seasonal differences of the capercaillie habitats with regard to the period of life were identified in this study. The majority of the capercaillie microhabitats were detected in dry, marshy and wet pure pine and mixed pine-spruce stands during winter and spring. The occupancy of microhabitats by individual birds varied also. The results of the comparison of capercaillie habitats and surrounding landscape shovved that the birds found a sufficient ųuantity of habitats of necessary stand structure in Dzūkija. Meanwhile, the number of habitats was limited by forest structure in Aukštaitija. The comparison of different sexes capercaillie microhabitats showed that females used younger stands than malęs.

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 16th May to 30th 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.

Subject and aim of the work: to improve and generalize the knowledge about the situation of capercaillie populations in Lithuania. Methods – investigations were accomplished in 2008–2009. The distribution, abundance and the localization of the mating places of capercaillies were examined using the social interviewing method. The data analysis near of the 19 mating places of capercaillie was made from the 1953 till now. 19 mating places of capercaillies were localized estimating GPS coordinates, respectively. Ages of trees, that are suitable for capercaillies feeding, were determined using the increment borer. Results. It was found, that capercaillies occur in 41 forest districts. The forest roads occurred in 94.7% (0.09 ha) of the capercaillie mating places. The main part of the mating places occurred in forest stands, growing in poor soils with normal watering (Nb). The mating places of capercaillie were found in Vacccinio-myrtillosa forest type. Capercaillies fed on the needles from 45–208 years old pines, which medium tree age of 80-90 yr. and in Pa – 100 yr. in Na and Nb forest sites. Almost all (73%) of mating places after half-century is still using of the capercaillies.