Abstract
A juvenile Black Bittern (Ixobrychus flavicollis) was captured and banded on November 7, 2006. The bird was caught in a mist net along a small stream in a narrow valley, at the base of Mt. Oyama in Kanagawa Prefecture, a little bit to the west of Tokyo, and was released after being measured and banded. Buff edges on both the wing coverts and back feathers identified the bird as a juvenile, but sex could not be determined. This species is widely distributed from southern Asia across Southeast Asia to Papua New Guinea and Australia. Observations in Japan date to 1970, but the first officially confirmed record was obtained from an island off Niigata Prefecture, along the Japan Sea side of Honshu Island, in 1981. In recent years confirmed observations have been made in the Izu Islands, but only one record had been obtained for the Honshu mainland. Of the four subspecies of the Black Bittern, subspecies flavicollis is found in China and Southeast Asia, and has been shown to migrate. Subspecies australis, on the other, inhabits Australia, and is not believed to migrate widely. Considering this distribution and migratory behavior, the captured bird is thought to most likely belong to subspecies flavicollis. The natural environment in which the bird was captured, consisting of dense shrub with stream and ponds nearby, was similar to that described as favorable to this subspecies. On the other hand, on the day of the capture a high wind had been blowing, and there is thus a strong possibility that the bird may have been blown in from the nearby Izu Islands.
