Unique Ecosystem - Birds
The black-tailed gull is one of the most common seagulls in Japan. It is about 47 cm in length and a wingspan reaching 120cm. The black-tailed gull has grey backs and upper wings, white plumage from the head to the belly, and a yellow bill with an eye-catching red and black dot. The tail is white, with a black band near the tip. The bird got its Japanese name umineko (“sea cat”) from its cat-like call. Here in Oki, around 300 black-tailed gulls breed collectively on Hirajima Island in Fuse area of Okinoshima Town, and during migration season, their calls echo the fishing ports. The birds usually fly to Hirajima Island every year in December, raise their young during spring and leave for the northern seas in July. They often prey on small fishes that swim near the surface of the sea when chased by larger fishes. Fishermen called such behaviour as toriyama (“bird hill”) and relied on it for fishing in the past.
Resident bird across Japan; winter or summer bird in the Oki Islands with some breeding