420 THE DESCENT OF MAN. 



have occurred, like those of display and pugnacity. Some 

 authors, however, argue that the song of the male cannot 

 serve to charm the female, because the females of some 

 few species, such as of the canary, robin, la-rk and bull- 

 finch, especially when in a state of widowhood, as Bech- 

 stein remarks, pour forth fairly melodious strains. In 

 some of these cases the habit of singing may be in part 

 attributed to the females having been highly fed and con- 

 fined,* for this disturbs all the usual functions connected 

 with the reproduction of the species. Many instances 

 have already been given of the partial transference of sec- 

 ondary masculine characters to the females, so that it is 

 not at all surprising that the females of some species should 

 possess the power of song. It has also been argued that 

 the song of the male cannot serve as a charm, because the 

 males of certain species, for instance of the robin, sing 

 during the autumn. \ But nothing is more common than 

 for animals to take pleasure in practicing whatever instinct 

 they follow at other times for some real good. How often 

 do we see birds which fly easily gliding and sailing through 

 the air obviously for pleasure? The cat plays with the 

 captured mouse and the cormorant with the captured fish. 

 The weaver-bird (Ploceus), when confined in a cage, 

 amuses itself by neatly weaving blades of grass between the 

 wires of its cage. Birds which habitually fight during the 

 breeding-season are generally ready to fight at all times; 

 and the males of the capercailzie sometimes hold their 

 Balzen or leks at the usual place of assemblage during the 

 autumn. | Hence it is not at all surprising that male birds 

 should continue singing for their own amusement after the 

 season for courtship is over. 



As shown in a previous chapter, singing is to a certain 

 extent an art, and is much improved by practice. Birds 

 can be taught various tunes, and even the unmelodious 

 sparrow has learned to sing like a linnet. They acquire 

 the song of their foster parents, and sometimes that of 



*D. Barrington, "Phil. Transact.," 1773, p. 262. Bechstein. 

 " Stubenvogel," 1840. s. 4. 



fThis is likewise the case with the water-ouzel; see Mr. Hepburn 

 in the "Zoologist," 1845-46, p. 1068. 



\ L. Lloyd, " Game Birds of Sweden," 1867, p. 25. 



Barrington, ibid, p. 264, Bechstein, ibiG, s. 5. 



