As a result, more than 70,900 birds of 65 kinds were observed. Among them are swan goose (VU), pochard (VU), Larus relictus (VU), Emberiza rustica (VU), Numenius arquata (NT), Calidris ruficollis (NT), Haematopus ostra-legus (NT) and Vanellus vanellus (NT).

In particular, more than 51,000 swan geese amounting to over 75 percent of their total numbers in the world were witnessed at the reserve. This is the highest record up to now.

The swan goose is an endangered species and its total number in the world is some 68,000. This fact shows once again that the reserve is naturally and geographically good to live in for migratory birds.

Mundok area was set as a migratory bird reserve in Juche 84 (1995), registered on the list of wetlands of international importance (Ramsar site) in 2018 and designated as the Network Site of the EAAF (East Asian-Australasian Flyway).

The reserve serves as a habitat for 22 species of endangered water birds and other birds amounting to over one percent of their total numbers in the world or East Asia. In spring and autumn, more than 80,000 water birds of 120 species fly into the reserve.