Age structure of the great tit (Parus major) breeding population in different types of habitats in the taiga zone of European Russia

The paper presents an analysis of the age structure of the Great Tit (Parus major) breeding population in two types of habitats with various compositions of forest stands and different distances from wintering places in Southern Karelia. We used data from monitoring birds nesting in artificial nest-boxes in the taiga forests of the Ladoga region at the Mayachino field station (60°46′ N, 32°48′ E) and forest stands in the territory of the PetrSU Botanical Garden in the outskirts of Petrozavodsk (61°51′ N 34°20′ E) in 2015-2021. It was estimated that there were differences in the structure of the bird population associated with the proximity of their wintering sites. One-year-olds predominated - 59 % of nesting birds (n = 118) in the taiga forests located far from human settlements. The level of philopatry there was low: 7.2 % of males and 5.8 % of females returned to the previous breeding area, and 0.3 % of marked chicks returned to the birth area. The breeding population of the study area was almost completely renewed every year and the proportion of immigrant birds was 96 %. The breeding population of plantings of the Botanical Garden consisted mainly of older individuals (72 %, n = 129) and by many indicators was close to the sedentary populations of Western Europe. The share of immigrants was only 57.8 %, residents - 33.8 %, birds of local origin - 8.4%. The level of philopatry was significantly higher than in the forests of the Mayachino field station: 34.7 % of males, 20 % of females returned to the former nesting area, and 0.8% of chicks returned to the birth area. The habitat preferences of individuals of different ages are weakly expressed and noticeable only in the taiga forests of the Mayachino field station. In conditions of low breeding density, the competition for territory was not observed. The distribution of individuals of different sexes and ages across the habitats may be associated with different time of their arrival in the breeding area. The results of the analysis show that the breeding population of the Great Tit in taiga forests far from human settlements and in suburban forests is formed by birds with different attitudes towards migration. A sedentary part of the regional population nests near wintering sites near settlements. Birds of older age classes with a high level of philopatry predominate there. Birds prone to seasonal movements of different distances nest away from urbanized territories, among them there are many first-year individuals with weak territorial ties.