География птиц в горах Северо-Восточной Азии

We studied geography of aviafauna of North-Eastern Asia mountains, namely the Verkhoyansk, Chersky, Suntar-Hayata, and Sette-Daban mountain ranges, and the Kolyma and Koryak uplands. We specified the distribution boundaries and residence status of 32 bird species within the area of about 300 000 km 2 . We confirmed the stability of the distribution boundaries for 20 species. The distribution border of a number of species runs along the Verkhoyansk range and the Sette-Daban range; that gives a reason to consider these ranges as important biogeographic boundaries within North-Eastern Asia. For the first time we encountered 32 species of birds outside the known breeding areas in the mountains of North-Eastern Asia, most of them (n=19) to the north of the known boundaries of theirs distribution. The share of the first-time encountered species in the avifauna of surveyed mountain regions is maximal in the southern branches of the Kolyma Upland, where 16 (21%) of 74 breeding species were recorded for the first time. The species found outside the known breeding areas were recorded at 1 to 15 sites at a distance of 20 to 1200 km from the known breeding areas. In 2014-2017 for the first time we found vast areas of stable breeding with a relatively high bird density for one group of species in the North-Eastern Asia, which could be considered parts of the main breeding area. For other species we identified only local, probably isolated territorial groups with a habitat area of no more than 50–100 km 2 that form the very edge of the species range in North-Eastern Asia. Perhaps, these are sporadic breeding areas or parts of the distribution range with prominently fluctuating boundary. The birds first-ever discovered in new breeding areas outside the known boundaries of the distribution range belong to different species. We assume that a number of such species appeared in the mountains of North-Eastern Asia as a result of breeding outside their distribution range or its expansion. The modern dynamics of the distribution range boundaries probably indicates the continuing dispersal of species and avifauna formation in the mountains of North-Eastern Asia under the climate change.