The Collaborative International Dictionary of English v.0.48:

Firebird \Fire"bird`\, n. (Zool.)
   The Baltimore oriole.
   [1913 Webster]

WordNet (r) 3.0 (2006):

firebird
    n 1: the male is bright red with black wings and tail [syn:
         scarlet tanager, Piranga olivacea, redbird,
         firebird]
    2: eastern subspecies of northern oriole [syn: Baltimore
       oriole, Baltimore bird, hangbird, firebird, Icterus
       galbula galbula]
    3: tropical American flycatcher found as far north as southern
       Texas and Arizona; adult male has bright scarlet and black
       plumage [syn: vermillion flycatcher, firebird,
       Pyrocephalus rubinus mexicanus]