The Black-tailed Gull (Larus crassirostris) is a medium-sized (46 cm) gull, with a wingspan of 126–128 cm. The bird is resident in East Asia, including China, Taiwan, Japan and Korea. It is a vagrant to Alaska and northeastern North America.
It has yellow legs and a red and black spot at the end of the bill. This gull takes 4 years to reach full adult plumage. As the name suggests, it has a black tail. The bird has a cat-like call, giving it its Japanese name — Umineko, "Sea cat", and Korean name — Gwaeng-yi gull, which means "cat" gull. In Hachinohe they are one of the 100 Soundscapes of Japan.