Common around Izu Is, Bonin Is and Volcano Is. Endemic. Breeds Dec-Jun. Population decrease non-breeding season; Jul-Oct. Early summer; Jun-Jul, seen in E Honshu; off Fukushima and Miyagi Pref.
Breeding sites are confirmed on Izu Is; Tadanae-jima; 760 nests in 2017, Hachijyo-kojima; 20 nests in 2017, Torishima; 97 nests in 2017, Bonin Is; Kitano-shima, Mukojima-torishima, Tatsumi-jima, Katsuodori-jima, Kogatsuotori-shima, Nishino-shima, and Volcano Is; Kita-iwo-jima, Minami-Iwo-jima.
Fig. 1. Adult.
Fig. 2. Adult. Same bird as Fig. 1.
Fig. 3. Adult. Same bird as Fig. 1.
Fig. 4. Adult. Same bird as Fig. 1.
Fig. 5. Adult.
Fig. 6. Adult.
Fig. 7. Adult. Worn bird often has broken forked tail.
Fig. 8. Common seen dozens, hundreds and often thousands of flocks.
Fig. 9. Adult. Worn bird often has white primary flash.
Fig. 10. Adult. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 11. Adult. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 12. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 13. Adult. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 14. Adult. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 15. Juvenile. Uniform flesh plumage.
Fig. 16. Juvenile. Same bird as Fig. 15.
Fig. 17. Juvenile. Same bird as Fig. 15.
Fig. 18. Juvenile. Same bird as Fig. 15.
Fig. 19. Juvenile. Same bird as Fig. 15.
Fig. 20. Foraging with Wilson’s Storm-Petrel. Same bird as Fig. 15.
Fig. 21. Fly with Wilson’s Storm-Petrel. Same bird as Fig. 15.
Fig. 22.
Fig. 23.
Fig. 24. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 25. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
Fig. 26. Off Mukojima Is, Bonin Is, Tokyo. 11 Apr 2019.
