Time-lapse camera photographs reveal arrival and breeding timing of short-tailed albatrosses Phoebastria albatrus

Monitoring the ecology of seabirds breeding on remote islands is often challenging. However, time-lapse cameras have enabled the surveillance of inaccessible sites. We examined arrival/departure movements and breeding timing of the endangered short-tailed albatross Phoe-bastria albatrus with time-lapse cameras on Torishima, a remote and uninhabited island in the northwestern Pacific, from November 2016 to June 2017. The photographic images revealed that the first arrival of the albatrosses on the island was on 7 October 2016, and the number of birds reached a peak of 506 on 5 November. The white pairs arrived and began incubating approximately 1 wk earlier than the white/brownish pairs. From the end of January, the number of birds repeatedly increased and decreased within a short period of time. The birds' movement out of the breeding colony often occurred synchronously with a rapid decline in the mean daily air pressure. Adult birds began to leave the colony in April. The number of chicks reached up to 200 at the beginning of May, but they all left the colony before 1 June. The processing of the photographic images taken during the incubation and early guard periods revealed that hatching failed in approximately 10% of the pairs. The validity of information collected by time-lapse cameras was confirmed by comparing it with the results of previous field studies. This study will contribute to the collection of essential information for monitoring and conserving seabirds breeding on remote islands where successive or frequent fieldwork is difficult.