Avifauna of Mountains in Northeastern Siberia

This study analyzes the ecological patterns of the altitudinal belts of differentiation of avian fauna and population in the mountains of northeastern Siberia. Data were collected during expeditions conducted in the summers of 2014–2016 in regions with distinct forest, subalpine, and alpine altitudinal belts. There are 150 species of breeding avifauna in the region. We have specified the distribution ranges of 26 bird species. Avifauna of the northeastern Siberia mountains develops in a framework of general zonal–landscape and altitudinal zonal patterns. The species diversity of birds decreases in the northern direction and from foothills to the mountain tops. The forest belt, subalpine belt, and alpine belt are breeding areas of 63–64 species (89–97%), 13–33 species (20–47%), and 8–15 species (12–21%), respectively. The wide vertical distribution of many bird species predetermines great general biodiversity, even in high-altitude belts with extreme environment conditions. In the northeastern Siberia mountains, the population density of birds and their abundance progressively decrease with altitude in most species. The bird population density is 312–594 ind./km2 for the forest belt, 57–266 ind./km2 for the subalpine belt, and 40–111 ind./km2 for the alpine belt.