138 E VOL UTION OF BIRD- SONG 



have several times heard this note uttered in exactly 

 the tone of the redwing by the mistle - thrush, 

 apparently as a call between the sexes. These 

 genera have different kinds of alarm-cries. 



The raptorial birds have simple screams or short 

 cries, sometimes consisting of very rapid repetitions 

 of an extremely brief sound, which is probably the 

 foundation -cry. In the duck family the young 

 produce a peet^ of the same nature as the peet of 

 young doves, pigeons, pheasant, partridge, fowl, etc. 

 — cries differing from those of most kinds of birds, 

 but similar to the whistling notes of some of the 

 AnatidcB, such as the shelduck when adult. Some 

 simple form of whistled note may, therefore, have 

 been the cry of the progenitors of these species ; and 

 in the same way the redwing's cry, and a simple 

 chirp or scream, may have been respectively primary 

 sounds in the thrushes and the falcons. 



In the finches, the twitter of the greenfinch and 

 its harsh song-note may be indicative of early modes 

 of address. The coo of the stock-dove {Cohimba 

 cenas\ more simple even than the notes of the 

 cuckoo, may be considered as a simple and early 

 tone, whence have diverged the sometimes elaborate 

 coos of the doves. The song of the ortolan, as 

 described by Dr. A. G. Butler (p. 121), or that of the 



