778 Transactions. 
It may be that the knowledge of the song does lie deep within— 
unexpanded—in a bud, as it were, which opens in response to the throbbing 
of the song of the species; so that the free young bird adopts the song 
that finds the readiest echo in its own breast. Young birds vary in the 
docility shown in learning the song of other birds—see Witchell (WE, 
pp. 175-76), Wood (WN, p. 59), Bolton (BH, vol. 1, pp. 11, 30, 56)—the 
acquired song smothering, or partially smothering, the natural song. The 
young cuckoo shows no docility, but on leaving the nest responds to the 
kind 
natural song of its kind. 
of emotion, the expression being most developed, most exuberant, when aus 
the spring-tide of the blood is flowing; and that in song the s 
emotion finds a powerful ally, seizing upon it, but not creating it, for the 2 
furthering of its own especial and occasional end. That which is true of 
human song is true, in a large degree, of bird-song ; nor does this ascribe 
to birds a greater aesthetic sense than has already been ascribed to them 
by those who maintain their song is purely sexual. 
LIST OF LITERATURE CITED. 
BC. Brouster, J. M., Cage and Chamber Birds, their Natural History. Translated 
from the German of J. M. Beckstein, M.D., with considerable additions 
;,; ; Compiled from various sources by Н. С. Adams. orporating 
the whole of Sweet's British Warblers, 1877. (Bohn’s Library.) 
um Botton, James, Harmonia Ruralis . . . British Song Birds. 2 v. 1845.. 
1900. 
DD. Darwin, Снавгеѕ, The Descent of Man. (Murray.) 1894. 
; . 1892. 
MF. Moptz, Ronznr, The Feathered Tribes of the British Islands. 2 v. 1861. 
RM. Rowawzs, GEORGE J OHN, Mental Evolution in Animals. 1883 
TB. ricus J. ARTHUR, The Biology of the Seasons. 1911. 
me я 
WS. Wa, GILBERT, The Natural History of PR Come, 1861. 
WW. Watson, Јонх, and Вглхсне Wixper, Woodlanders and Field Folk. 1907. 
YH. Yarrevt, \пллам, А History of British Birds. Ed. 3, 3 v., 1856; ed. 44 eae 
1871-74. 
Ad 
PII: н 
