The National Institute of Environmental Research has conducted a migratory shorebird census in major tidal flats in Korean West Coast like Ganghwado (island), Yeongjongdo (island), Asanman (bay), Geumgang (river) estuary, Yubudo (island), Mangyeonggang(river) and Dongjingang(river) from 1993 to 2002.

In the last ten years, 173,000 to 410,000 and 99,000 to 244,000 shorebirds visited West Coast in spring and autumn respectively. It is 5.5%(in autumn) to 9.3% (in spring) of migratory shorebirds who travel from East Asia to the Oceanic Islands.

Among 50 species visited Korean West Coast, Great Knot (Calidris tennirostris) and Dunlin (Calidris alpina sakhalina) are the most common species. Mangyeonggang(river) and Dongjingang(river) are the most popular visiting grounds for the shorebirds with 60,000 to 240,000 (in spring) and 50,000 to 140,000(in autumn) visitors, followed by Asanman (bay), Namyangman (bay), Geumgang (river) estuary, Ganghwado (island), and Yeongjongdo (island).

In Namyangman (bay), 20 thousand and 10 thousand migratory birds have visited in spring and autumn respectively. However, after the construction of Hwa-ong seawall, the number reduced to 12,000 and 5,700 in spring and autumn respectively due to the changes in habitat and ecosystem.

Especially, endangered Spoonbilled Sandpiper (Eurynorhynchus pygmens) and Spotted Greenhank (Tringa guttifer) have visited West Coast. 50 to 200 individuals, or 3% of world Spoonbilled Sandpiper (Eurynorhynchus pygmens) population (estimated from 4,000 to 6,000),and 60 to 150 individuals or 6 to 18% of world Spotted Greenhank (Tringa guttifer) population (estimated as 1,000) have visited West Coast per year.

According to this census, Korean West Coast is one of the most important visiting grounds for migratory shorebirds, especially endangered Spoonbilled Sandpiper and Spotted Greenhank. This long-term census is expected to contribute to a long-term environmental preservation plan for the West Coast ecosystem.