Black-tailed gulls are a Laridae family bird whose Japanese name “Umineko (Sea Cat)” is derived from its voice resembling a cat’s. They fly over in March to form a colony, lay eggs, raise children, and leave around July to August. From the east end of the island to neighboring Shirataki Island, Funama Island, and Ashikabae are their major habitation spots, whose number is said to be more than 6,000. The rock walls of crystalline schist and rocky beach are covered in white with the birds. This is known as the southern limit of nesting, and they fly around when a sightseeing boat approaches.
The strait between here and Cape Sada in Shikoku connects the Seto Inland Sea and the outer ocean, with both Kanmon and Naruto Straits. As it is called “Hayasui-no-Seto (fast-absorbing),” the current whirls rapidly, being one of the most dangerous zones of the ocean. This raised the people of Amabe, known to operate their ships very well, who created the fishermanship of Bungo.
Shiinetsuhiko, a famous god in the Japanese Legendary narrative of Eastern Expedition of the Emperor Jinmu, Isago and Masgo sisters who were female divers, and the goddess of the Strait, Hayasui Hime, are all enshrined in the former Town of Saganoseki (current City of Oita). And now, they are passed down in the spirits of fishermen who go after Sekiaji and Sekisaba (Horse Mackerel and Chub Mackerel).
The name “Seki” comes from the key point in maritime traffic, which originates from the barriers and gates of the sea routes. They became the front line of modern Japan’s homeland defense. Takashima Island, a long deserted island, was temporarily settled by the samurai who lost their belongings, but they were removed from the island and it was fortified along with the peninsula beginning in 1920. Facilities of the “Houyo Fortress” including gun batteries and ammunition depots are now buried in the ground or in the grass, all over the island.