Breeding of the tawny owl Strix aluco in Finland: responses of a southern colonist to the highly variable environment of the north

Large-scale patterns and variations in the occurrence and breeding of the Tawny Owl Strix aluco in Finland was studied in relation to the availability of small voles and winter ing birds as well as to general weather conditions of the preceding winter. In 1986-2000, pronounced three-year cycles in the numbers of occupied territories as well as nesting at- tempts recorded were less regular near the southern coast than elsewhere in Finland. On average, 64.7