The Collaborative International Dictionary of English v.0.48:

Thornbill \Thorn"bill`\, n. (Zool.)
   Any one of several species of small, brilliantly colored
   American birds of the genus Rhamphomicron. They have a
   long, slender, sharp bill, and feed upon honey, insects, and
   the juice of the sugar cane.
   [1913 Webster]
   [1913 Webster]

WordNet (r) 3.0 (2006):

thornbill
    n 1: any of various South American hummingbirds with a sharp
         pointed bill