Pterodroma solandri were observed in the North Pacific during several cruises on the R. V. Tansei Maru and R. V. Hakuho Maru from 1980 through 1986. (1) P. solandri concentrated mainly along the Polar front in the Northwest Pacific during the breeding season and distributed widely from west to east in the North Pacific during the nonbreeding season. (2) The closest sightings of this bird to land were made in the vicinity of Miyake Is. in February and another in the area 100 nautical miles offshore of Sanriku in September. (3) P. solandri occurred in areas where surface water temperatures ranged from 8°C to 28°C. They were particularly abundant in areas with water temperature of 8°C in May and in another months. They distributed on average in areas with water temperatures ranged from 12°C to 26°C. From the above observations it is concluded that they favour the warm areas as the circumstances of breeding grounds and moreover they are the kind of species which select areas of cool waters as habitats.
A study on migratory activities of the short-tailed shearwaters, Puffinus tenuirostris, was conducted during a voyage of trans-North Pacific from Japan to the United States. Its mass mortality was found occurring off Kashima-nada, Honshu, early June 1983. No weakened nor dead birds were observed on the navigation routes from Toyohashi to Portland, via the Hawaii, and from Portland to the Kuril Islands, via the Unimak Pass and Attu Island. A first floating emaciated bird occurred on June 5, when we came to off Hokkaido; in the waters south of it, along Tohoku to Kashima-nada, most of the 294 birds we encountered on June 6 were apparently emaciated, with 3 floating birds already dead. This sea area well coincided with the northern limit of the mass mortality recorded in that year, and was within the Kuroshio warm current. This suggests that birds which were strong enough to pass into the northern cold current, richer in marine productivity, would survive and that those exhausted not reaching there would die within the Kuroshio Current, owing to the food shortage.
I observed land-birds on the Kita-Daito Island (25°57'N, 131°18'E) between 29th-31st January 1984. Fifteen species (13 families) were recorded, including new records of Phasianus colchicus, Vanellus vanellus, Motacilla alba, Pericrocotus divaricatus, Turdus pallidus and T. naumanni. I assume that P. colchicus were artificially introduced.
On May 31st 1986, while observing a pair of Blakiston's Fish Owls (Ketupa blakistoni) in their breeding territory, I witnessed a unique encounter between the male owl and a Black-crowned Night Heron (Nycticorax nycticorax). The Black-crowned Night Heron is very rare in Hokkaido. It does not breed there (WBSJ, 1981), and in fact was not recorded there at all by WBSJ (1982), although OSJ (1974) does mention records from that prefecture. The early summer of 1986 saw an unprecedented invasion of herons and egrets of several species in southeastern Hokkaido (Brazil, in press) and clearly a single night heron arrived during this influx. Since, in Japan, the fish owl is confined to the island of Hokkaido, and now mostly to the eastern third, it is highly unlikely that these two species have encountered each other in this country before. The ranges of the two species do not overlap in the Soviet Union either (Flint et al., 1984).
A wondering White-naped Crane (Grus vipio) was observed by the Authors on the Japan Sea coast of Niigata Prefecture on 9th March 1986. This bird is presumed to be the same one which had been observed while wintering in Ishikawa Prefecture.