The common nightingale, rufous nightingale or simply nightingale, is a small passerine bird which is known for its powerful and beautiful song, often described as one of the most beautiful sounds in nature. An Old World flycatcher, it belongs to a group of more terrestrial species, often called chats. Its range partly overlaps with that of the more northerly thrush nightingale, a closely related species with which hybrids have occurred.