This common loon shown swimming alone on a Canadian lake has a large, heavy body with a thick and pointed black bill. In the breeding season the plumage, head and neck are black with white bands on the neck and white spots on the back; in the winter the crown, hindneck and upperparts dark grey and the throat and underparts are white. The call of the loon, which occurs usually at night and during migration, is a loud, wailing laugh or a mournful yodel and has been described as "one of the most striking wilderness sounds, a strange, sad, mournful, unearthly cry, half laughing, half wailing".