noun (n)

• the characteristic sound produced by a bird(noun.communication)

  Synonym:
  birdsong, call, song
  

  source: wordnet30
• a device for imitating a birdcall(noun.artifact)

  source: wordnet30
• A sound made in imitation of the note or cry of a bird for the purpose of decoying the bird or its mate.(noun)

  source: webster1913