Swinhoe's Storm Petrel

Swinhoe's storm petrel is a small, all-brown seabird, 18–21 cm long with a wingspan of 45–48 cm, distinctly larger than the European storm petrel. It is essentially dark brown in all plumages and has a fluttering flight, picking planktonic food from the ocean surface. In structure it most resembles Leach's storm petrel, with a forked tail, longish wings and similar flight, but it lacks a white rump and its call differs (Wikipedia, general species account).

It breeds on islands in the north-west Pacific off the Russian Far East, China, Japan and Korea, including Verkhovsky Island south of Vladivostok, nesting in colonies close to the sea in rock crevices and laying a single white egg. It spends the rest of the year at sea, and in winter migrates south and west to the northern Indian Ocean and Arabian Sea (Wikipedia, general species account).