Семенов-Тян-Шанский О.И. Экология тетеревиных птиц. Москва, 1959.

June, solid line — average temperature of the coldest 10-days period of June; columns below — age ratios of population (hatched part — juveniles, white part — adults). 95. Weather of breeding period and age ratios in Capercaillie populations in Lapland (left) and Petshora-Ylytsh Reserve (right). For further explications see fig. 94 and the summary. 96. Counts of Rock Ptarmigan on Tshuma-tundra in April; number of specimens for one day trip. 97. Age composition of Capercaillie population in Upper Petshora district; sparse hatched — in open season, dense hatched — in spring hunting season. 98. Dynamics of Capercaillie population based on census figures; white columns — immature birds, hatched columns — the adults. All photographs, excluding N 16, are made by O. Semenov-Tian- Shansky. 309