The blue manakin or swallow-tailed manakin is a small species of bird in the family Pipridae. It is found mainly in the Atlantic Forest of south-eastern Brazil, eastern Paraguay and far north-eastern Argentina. Its typical habitat is wet lowland or montane forest and heavily degraded former forest. Males have a bright blue body, black head wings and tail and a red crown. Females and juveniles are olive-green. At breeding time, males are involved in lekking behaviour when they sing and dance to impress females. This is a common species with a wide range, and the International Union for Conservation of Nature has rated its conservation status as being of "least concern".