The Collaborative International Dictionary of English v.0.48:

Bird of paradise \Bird" of par"a*dise\ (Zool.)
   The name of several very beautiful birds of the genus
   Paradisea and allied genera, inhabiting New Guinea and the
   adjacent islands. The males have brilliant colors, elegant
   plumes, and often remarkable tail feathers.
   [1913 Webster]

   Note: The Great emerald (Paradisea apoda) and the Lesser
         emerald (Paradisea minor) furnish many of the plumes
         used as ornaments by ladies; the Red bird of paradise
         is Paradisea rubra or Paradisea sanguinea; the
         Golden bird of paradise is Parotia aurea or
         Parotia sexsetacea; the King bird of paradise is
         Cincinnurus regius. The name is also applied to the
         longer-billed birds of another related group
         (Epimachin[ae]) from the same region. The
         Twelve-wired bird of paradise (Seleucides alba) is
         one of these. See Paradise bird, and Note under
         Apod.
         [1913 Webster]

WordNet (r) 3.0 (2006):

bird of paradise
    n 1: a tropical flowering shrub having bright orange or red
         flowers; sometimes placed in genus Poinciana [syn: bird of
         paradise, poinciana, Caesalpinia gilliesii, Poinciana
         gilliesii]
    2: ornamental plant of tropical South Africa and South America
       having stalks of orange and purplish-blue flowers resembling
       a bird [syn: bird of paradise, Strelitzia reginae]
    3: any of numerous brilliantly colored plumed birds of the New
       Guinea area