Wilson’s Storm-Petrel

Wilson’s Storm-Petrel Oceanites oceanicus

Migration visitor. Common around Izu Is, E Honshu; off Chiba, Ibaraki, Iwate Pref, May-Jul since 2007. 

Most of birds around Japan are Adults, and Juvenile are less than 5%. Sometimes seen flocks of hundreds birds.

Fig. 1. Adult. Off Chiba Pref. 23 Jul 2018. Adult and subadult wing molt mainly Mar-Sep; 1st year mainly Jul-Jan. This bird’s wing already molt 4 and 5 primaries in Jul.
Fig. 2. Adult. Off Chiba Pref. 23 Jul 2018.
Fig. 3. Adult. Off Chiba Pref. 23 Jul 2018.
Fig. 4. Adult. Off Chiba Pref. 23 Jul 2018.
Fig. 5. Adult. Off Chiba Pref. 23 Jul 2018.
Fig. 6. Foraging with Matsudaira’s Storm-Petrel. Off Chiba Pref. 23 Jul 2018.
Fig. 7. Foraging. Off Chiba Pref. 23 Jul 2018.
Fig. 8. Adult. Off Chiba Pref. 23 Jul 2018.
Fig. 9. Adult.
Fig. 10. Adult.
Fig. 11. Adult. Sometimes legs pulled in.
Fig. 12. Presumed Juvenile. This bird doesn’t molt primaries.
Fig. 13. Presumed Juvenile.
Fig. 14. Presumed Juvenile. Off Iwate Pref. 30 Jun 2018.
Fig. 15. Adult. Off Iwate Pref. 30 Jun 2018.
Fig. 16. Foraging with Northern Fulmar. Off Iwate Pref. 30 Jun 2018.