Abstract
1) The results of recent observations of the Short-tailed Albatross on Torishima by Takenouchi in the 1973/74 season and by the author from 1976/77 were documented in a little detail.
2) In 1973/74 although at least 40 clutches seemed to have been laid, only 11 chicks fledged. In 1976/77 about 70 birds were sighted frequently and more than 40 pairs could have had their clutches, but only 15 young fledged. Compared with Tickell's observation of 24 fledglings in May 1973, the annual fledgling production was low recently. Breeding success of about one-third in recent seasons might be lower than the average value 43% a decade or so ago.
3) Among possible factors respensible, a change in vegetation characteristics at the nesting site was pointed out to be most probable: the grass Miscanthus sinensis v. condensatus which was tall and dominant at the east area before has become subdominant and replaced by the short herbaceous plant Crysanthemum pacificum; but in the center of the west area vegetation has been removed due to trampling by albatrosses. Most chicks survived were close to the vegetation.
4) Although the Short-tailed nested preferentially on the bare, flat ground in those days when they were abundant, for the present-day population nesting on the restricted site, a steep volcanic ash slope vulnearable to erosion, washout and constant fall-out of ash from the upper-parts of the island, the vegetation cover should without doubt improve success by stabilising the nesting ground and by protecting the broods from strong winds, and increase the nest carrying capacity making no inconvenience to their take-off.
5) From these considerations, some problems for the conservation measures such as transplanting the grass and use of fertilizer at the breeding ground, and the extermination of terrestrial predators are discussed.
6) Some observations on "raft" behaviour of the Short-tailed Albatross and the current breeding status of the Black-footed Albatross were also reported.
