The status of 37 species of breeding seabirds in Japan has been reported by Hasegawa (1984). However, since then, no report has been made. The author was involved in the launch of seabird monitoring for the Monitoring site 1000 project by the Ministry of the Environment in 2004. In the over 15 years since then, population and habitat have been surveyed in 30 major breeding areas, including 80 islands and islets in Japan. In this paper, the previous studies including reports based on this project and the seabird colony database were reviewed. The populations of many species at various islands declined, possibly because of introduced predators and human disturbance. The nesting habitats of most of the seabird breeding areas had deteriorated. Therefore, the continuous monitoring of the change of the population and nesting habitat and quick operation of appropriate conservation measures, (eradication of introduced predators and redacation of human disturbance) are required. In this paper, 1) distribution of seabirds, 2) monitoring seabird survey, 3) current status, 4) introduced predators, and 5) conservation activities are summarized. Further 1) necessity of long-term monitoring of seabirds, 2) extermination of introduced predators, 3) reduction of anthropogenic disturbances, and 4) issues of conservation measures are discussed.
