The Collaborative International Dictionary of English v.0.48:

Bird \Bird\ (b[~e]rd), v. i.
   1. To catch or shoot birds.
      [1913 Webster]

   2. Hence: To seek for game or plunder; to thieve. [R.] --B.
      Jonson.
      [1913 Webster]

   3. to watch birds, especially in their natural habitats, for
      enjoyment; to birdwatch.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Bird \Bird\ (b[~e]rd), n. [OE. brid, bred, bird, young bird,
   bird, AS. bridd young bird. [root]92.]
   1. Orig., a chicken; the young of a fowl; a young eaglet; a
      nestling; and hence, a feathered flying animal (see 2).
      [1913 Webster]

            That ungentle gull, the cuckoo's bird. --Shak.
      [1913 Webster]

            The brydds [birds] of the aier have nestes.
                                                  --Tyndale
                                                  (Matt. viii.
                                                  20).
      [1913 Webster]

   2. (Zool.) A warm-blooded, feathered vertebrate provided with
      wings. See Aves.
      [1913 Webster]

   3. Specifically, among sportsmen, a game bird.
      [1913 Webster]

   4. Fig.: A girl; a maiden.
      [1913 Webster]

            And by my word! the bonny bird
            In danger shall not tarry.            --Campbell.
      [1913 Webster]

   Arabian bird, the phenix.

   Bird of Jove, the eagle.

   Bird of Juno, the peacock.

   Bird louse (Zool.), a wingless insect of the group
      Mallophaga, of which the genera and species are very
      numerous and mostly parasitic upon birds. -- Bird mite
      (Zool.), a small mite (genera Dermanyssus,
      Dermaleichus and allies) parasitic upon birds. The
      species are numerous.

   Bird of passage, a migratory bird.

   Bird spider (Zool.), a very large South American spider
      (Mygale avicularia). It is said sometimes to capture and
      kill small birds.

   Bird tick (Zool.), a dipterous insect parasitic upon birds
      (genus Ornithomyia, and allies), usually winged.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bird
    n 1: warm-blooded egg-laying vertebrates characterized by
         feathers and forelimbs modified as wings
    2: the flesh of a bird or fowl (wild or domestic) used as food
       [syn: bird, fowl]
    3: informal terms for a (young) woman [syn: dame, doll,
       wench, skirt, chick, bird]
    4: a cry or noise made to express displeasure or contempt [syn:
       boo, hoot, Bronx cheer, hiss, raspberry, razzing,
       razz, snort, bird]
    5: badminton equipment consisting of a ball of cork or rubber
       with a crown of feathers [syn: shuttlecock, bird,
       birdie, shuttle]
    v 1: watch and study birds in their natural habitat [syn:
         bird, birdwatch]