Lake Tofutsu is a registered lake under the Ramsar Convention and is renowned as a paradise for wild birds. The name, Tofutsu, comes from the Ainu word, to-put, which means the inlet of the lake. In the lake the water from the river is mixed with the water from the sea, adding extra nutrients and hence creating a rich environment for living creatures.
Before the arrival of winter, over 50 migratory birds including whopper swans and ducks stop at this lake before continuing their southward journey. Throughout the year some 250 species of wild birds visit the lake and in recent years the breeding of Japan’s Special Natural Monument, the red-crested cranes, has been confirmed here.