Abstract
(1) Between 1874 to 1985, 115 Oriental Ibises Threskiornis melanocephalus were recorded in 77 occasions in Japan. The number of records is increasing in recent years, probably due to the increase of bird watchers.
(2) Of the 77 records, 84.4% were single individuals, while the largest flock was composed of 18 birds. Almost all the birds (92.1%) were juveniles.
(3) The records were made in 27 prefectures throughout Japan, and 80.5% of recorded localities distributed between 32°N and 36°N. The ibises were frequently observed at Gyotoku (Chiba Pref.), Yashiro (Hyogo Pref.), and Arasaki (Kagoshima Pref.).
(4) Almost all of them were feeding at marsh or margins of streams and pools 2 to 3km distant from the roost, associating with egrets.
(5) The occurrence of ibises was independent of seasons.
(6) The duration of staying of the ibises at the given localities was only one day in more than
half of the resords (54.5%); however, in some cases (7.7%), ibises stayed more than one year.
(7) Estimated population of the Oriented Ibis in the midto late Yedo era (1700-1850) seems to be large compared with that in recent years; however, there was no evidence of breeding in Japan.
