Hydrobates leucorhous (Leach's storm-petrel)

The European storm petrel, British storm petrel or just storm petrel (Hydrobates pelagicus) is a seabird in the northern storm petrel family, Hydrobatidae. It is the only member of the genus Hydrobates. The small, square-tailed bird is entirely black except for a broad white rump and a white band on the underwings, and it has a fluttering, bat-like flight. The large majority of the population breeds on islands off the coasts of Europe, with the greatest…

— Wikipedia