COMMENTS ON 'THE BIRD FANCYER'S DELIGHT': TOGETHER WITH NOTES ON IMITATION IN THE SUB-SONG OF THE CHAFFINCH.

The 'Bird Fancyer's Delight' (1717) is considered in the light of modern knowledge of the process of song-learning in birds. Some conclusions (if Baron von Pernau (1716) as to song imitation are also discussed. A new example of the ability of the Chaffinch to incorporate song phrases from other species into its sub-song is given. It is suggested that there is an important difference between its true song and its sub-song in this respect and that this difference may throw light on the ability of some other finches to learn alien songs.