Source : Webster's Revised Unabridged Dictionary (1913)

Birdcall \Bird"call`\, n.
   1. A sound made in imitation of the note or cry of a bird for
      the purpose of decoying the bird or its mate.

   2. An instrument of any kind, as a whistle, used in making
      the sound of a birdcall.

Source : WordNet®

birdcall
     n 1: the characteristic sound produced by a bird; "a bird will
          not learn its song unless it hears it at an early age"
          [syn: {call}, {birdsong}, {song}]
     2: a device for imitating a birdcall