The birds of paradise are members of the family Paradisaeidae of the order Passeriformes. They are found in eastern Indonesia, Torres Strait Islands, Papua New Guinea, and eastern Australia. [...] Most species have elaborate mating rituals, with the Paradisaea species using a lek-type mating system. Others, such as the Cicinnurus and Parotia species, have highly ritualized mating dances.

(from Wikipedia)
And this is how they look:

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