Abstract
The flock-migration of birds of prey has only been known in Butastur in Japan. But the writer observed about 1, 500 Japanese Honey Buzzards migrating over Mt. Adachi in Kokura City on September 23, 1961. On the same day 50 migrating birds were observed over Moji by Mr. Takahashi, and on October 15 the writer also observed 11 at Saganoseki, Oita Prefecture. These observations suggest its migratory route figured in Fig. 1.
