The small Hokkaido island, which is part of the Tianyu National Park in the summer, is a small Hokkaido island about 12 kilometers around the Sea of Japan. It is a breeding ground for the world's few seabirds, including winter birds, flat-billed seabirds, pointed-billed sea ducks and other rare seabirds to nest. The strong winds of the Sea of Japan. The rough waves have formed a cliff, which is the best place for seabirds to resist foreign invasion. The landscape of seabirds flying in the sky from spring to early summer is amazing!