480 THE DESCENT OF MAN 



although the price of an ordinary male chaffinch is only six- 

 pence, Mr. Weir saw one bird for which the bird-catcher 

 asked three pounds; the test of a really good singer being 

 that it will continue to sing while the cage is swung round 

 the owner's head. 



That male birds should sing from emulation as well as 

 for charming the female, is not at all incompatible; and 

 it might have been expected that these two habits would 

 have concurred, 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, lark, and bullfinch,' 

 especially when in a state of widowhood, as Bechstein re- 

 marks, 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 confined,''' 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 secondary mascu- 

 line characters to the female, so that it is not at all sur- 

 prising 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 ani- 

 mals 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 breed- 

 ing season are generally ready to fight at all times; and the 



^ D. Barrington, "PM. Transact.," 1113, p. 262. Bechstein, "Stuben- 

 V6gel," 1840, s. 4. 



" This is likewise the case with the water-ouzel ; see Mr. Hepburn in the 

 "Zoologist," 1845-1846, p. 1068. 



