Birds of the Lake Basins of the Southern Part of Chersky Mountain Ridge
New data and analysis of the avifauna and bird species abundance are given for the lake systems of the southern part of the Chersky mountain ridge. In August - October of 2018 and in June and August of 2021, bird studies of lake basins of Ui, Momontay, Malyk, Darpir and Urultun lakes, situated at altitudes of 818-1234 meters above the sea level, were performed. 81 bird species were registered, of which 69 were recorded during breeding season, including 56 species referred to breeding and 13, to summering species. In comparison to the bird fauna of neighboring mountain areas, the avifauna of the studied lake systems is characterized by low species diversity, low percentage of widely-distributed species, and high percentage of boreal-hypoartcic and hypoarctic types of zonal-landscape distribution with clearly dominating species of the Siberian origin. Species content of the studied area is similar to that of the subalpine belt of Yakutia’s northern mountains in the presence of Long-toed Stint, Red-throated Pipit and Pallas’ Reed Bunting as well as, contrary to the subalpine belt of the Kolyma Highland, in the absence such species as Pine Grosbeak, Siberian Rubythroat, Pallas’ Leaf Warbler, and Arctic Warbler on these elevations. On the other hand, the presence of such species as Ringed Plover and Dusky Warbler and the absence of Bluethroat is similar to the bird fauna of the Kolyma Highland subalpine belt. High abundance of both Beringian and Green-headed Yellow Wagtails sharing their habitats appeared to be a unique feature of the studied area. Confirmed breeding of Fieldfare on the elevations over 1000 m above the sea level significantly increases the knowledge on the distribution and ecology of this species.