vireo gilvus

from The Collaborative International Dictionary of English v.0.48
Vireo \Vir"e*o\, n. [L., a species of bird.] (Zool.)
   Any one of numerous species of American singing birds
   belonging to {Vireo} and allied genera of the family
   {Vireonidae}. In many of the species the back is greenish, or
   olive-colored. Called also {greenlet}.
   [1913 Webster]

   Note: In the Eastern United States the most common species
         are the white-eyed vireo ({Vireo Noveboracensis}), the
         red-eyed vireo ({Vireo olivaceus}), the blue-headed, or
         solitary, vireo ({Vireo solitarius}), the warbling
         vireo ({Vireo gilvus}), and the yellow-throated vireo
         ({Vireo flavifrons}). All these are noted for the
         sweetness of their songs.
         [1913 Webster]