Surface area: 53,304 ha
Elevation: 714 m

Protection status: Unprotected.

Site description: The site is located in the east of Tamsag depression, 30km southwest of Sumber soum center, Dornod province and it comprises the group of small lakes, located in 1-2km from each other. There are Shuumar, Bayan, Bayanburd and many other lakes in Tashgai Lake depression. Some of the lakes are fully surrounded by reeds, while some are partially surrounded by reeds and rushes. The major land use of Tsahgain depression is livestock grazing and the northern small hills are used for agriculture. Land degradation of the main area with reeds, where waterbirds live and wildfires occur every spring and autumn are major threats to the site. Illegal hunting of birds has been reported. In recent years oil explorations are carrying out in Tamsag region, leading to increase of motor vehicles and it has potential to cause threats to Tashgain Tavan Lakes.

Importance for birds: Globally threatened bird species such as Swan Goose (Anser cygnoides), Baer's pochard (Aythya baeri), White-naped Crane (Grus vipio), Red-crowned Crane (Grus japonensis) and Great Bustard (Otis tarda) occur at the site. Bird species restricted to the Eurasian steppe and desert biomes occur here. Great Crested Grebe (Podiceps cristatus), Grey Heron (Ardea cinerea), Whooper Swan (Cygnus Cygnus), Ruddy Shelduck (Tadorna ferruginea), Common Shelduck (Tadorna tadorna), Gadwall (Anas strepera), Common Pochard (Aythya ferina), White-naped Crane (Grus vipio), Demoiselle Cranes (Anthropoides virgo) and Northern Lapwing (Vanellus vanellus) gather in flocks, exceeding 1% of their flyway populations. Reed parrotbill (Paradoxornis heudei), whose breeding range defines the Mongolia third area, lives only in this lake and reeds around confluence of Khalkh river enters to Buir Lake in few numbers. Wildfire and degradation of the land are influencing to the number of these birds. The site also an important area for White-naped Crane (Grus vipio) and Demoiselle Cranes (Anthropoides virgo), which gather around agricultural fields of the site in the springs and autumns in vast numbers.

Special flora and fauna: Mongolian Gazelle (Procapra gutturosa), Grey Wolf (Canis lupus), Red Fox (Vulpes vulpes) and Corsac Fox (V.corsac), listed in Red Data Book of Mongolia occur at the site. Mongolian Gazelle (Procapra gutturosa) graze here only in the winters. The new fish species to Mongolia, Lefua Lefua costata, was found at Shine Gol in 1996 and Azragiin and Tamsag rivers in 1999, which enters to Tashgain Tavan Lakes.