Sado is famous as the major breeding area for the Japanese Crested Ibis.

One was the Japanese Crested Ibis.

The last known Japan-born Japanese Crested Ibis died in captivity in 2003 on the island.

A 2010 study of mitochondrial DNA of the spoonbills by Chesser and colleagues, which included E. ruber, Nipponia nippon and Threskiornis aethiopicus found that E. ruber was an early offshoot and not closely related to a clade containing the spoonbills and old world ibises.