Chap. XVI.] THE YOUXG LIKE BOTH ADULTS. 205 



than it really was. This may be illustrated by the practice 

 followed by some bird-fanciers, who full out a few feathers 

 from the breasts of nestling bullfinches, and from the head 

 or neck of young gold-pheasants, in order to ascertain their 

 sex ; for in the males these feathers are immediately re- 

 placed by colored ones. 36 The actual duration of life is 

 known in but few birds, so that we can hardly judge by 

 this standard. And with reference to the period at which 

 the powers of reproduction are gained, it is a remarkable 

 fact that various birds occasionally breed while retaining 

 their immature plumage. 37 



The fact of birds breeding in their immature plumage 

 seems opposed to the belief that sexual selection has played 

 as important a part as I believe it has in giving ornament- 

 al colors, plumes, etc., to the males, and, by means of 

 equal transmission, to the females of many species. The 

 objection would be a valid one, if the younger and less 

 ornamented males were as successful in winning females 

 and propagating their kind, as the older and more beauti- 

 ful males. But we have no reason to suppose that this is 



36 Mr. Blyth, in Charlesworth's 'Mag. of Nat. Hist.' vol. i. 1837, p. 

 300. Mr. Bartlett has informed me in regard to gold-pheasants. 



37 1 have noticed the following cases in Audubon's c Ornith. Biogra- 

 phy. The Redstart of America' (Muscicapa ruticilla, vol. i. p. 203). 

 The Ibis tantalus takes four years to come to full maturity, but sometimes 

 breeds in the second year (vol. iii. p. 133). The Grus Americanus takes 

 the same time, but breeds before acquiring its full plumage (vol. iii. p. 

 211). The adults of Ardea cmrulea are blue and the young white; and 

 white, mottled, and mature blue birds may all be seen breeding together 

 (vol. iv. p. 58): but Mr. Blyth informs me that certain herons apparently 

 are dimorphic, for white and colored individuals of the same age may be 

 observed. The Harlequin duck (Anas histrionica, Linn.) ta^es three 

 years to acquire its full plumage, though many birds breed in the second 

 year (vol. iii. p. 614). The Whiteheaded Eagle (Falco leucocephalus, vol. 

 Iii. p. 210) is likewise known to breed in its immature state. Some spe- 

 cies of Oriolus (according to Mr. Blyth and Mr. Swinhoe, in ' Ibis,' July 

 1863, p. 68) likewise breed before they attain their fall plumage. 



