BIRDS— YOUNG LIKE ADULT FEMALES. 461 



IV. When the adult male resembles the adult female the young 

 of both sexes in their first plumage resemble the adults, as with 

 the kingfisher, many parrots, crows, hedge-warblers. 



V. When the adults of both sexes have a distinct winter and 

 summer plumage, whether or not the male differs from the female, 

 the young resemble the adults of both sexes in their winter dress, 

 or much more rarely in their summer dress, or they resemble the 

 females alone. Or the young may have an intermediate char- 

 acter; or again they may differ greatly from the adults in both 

 their seasonal plumages. 



VI. In some few cases the young in their first plumage differ 

 from each other according to sex; the young males resembling 

 more or less closely the adult males, and the young females more 

 or less closely the adult females. 



Class I. — In this class, the young of both sexes more or less 

 closely resemble the adult female, whilst the adult male differs 

 from the adult female, often in the most conspicuous manner. In- 

 numerable instances in all Orders could be given; it will suffice to 

 call to mind the common pheasant, duck, and house-sparrow. The 

 cases under this class graduate into others. Thus the two sexes 

 when adult may differ so slightly, and the young so slightly from 

 the adults, that it is doubtful whether such cases ought to come 

 under the present, or under the third or fourth classes. So again 

 the young of the two sexes, instead of being quite alike, may differ 

 in a slight degree from each other, as in our sixth class. These 

 transitional cases, however, are few, or at least are not strongly 

 pronounced, in comparison with those which come strictly under 

 the present class. 



The force of the present law is well shown in those groups, in 

 which, as a general rule, the two sexes and the young are all alike; 

 for when in these groups the male does differ from the female, as 

 with certain parrots, kingfishers, pigeons, &c., the young of both 

 sexes resemble the adult female.^ We see the same fact exhibited 

 still more clearly in certain anomalous cases; thus the male of 



= See, for instance, Mr. Gould's account ('Handbook to the Birds of 

 Australia,' vol. 1. p. 133) of Cyanalcyon (one of tlie Kingflsliers) in 

 whicli, liowever, tiie young- male, though resembling the adult female, 

 is less brilliantly colored. In some species of Daoelo the miales have 

 blue tails, and the females brown ones; and Mr. R. B. Sharpe informs 

 me that the tail of the young male of D. gaudichaudi is at first brown. 

 Mr. Gould has described (ibid. vol. ii. pp. 14, 20, 37) the sexes and the 

 young of certain black Cockatoos and of the King Lory, with which 

 the same rule prevails. Also Jerdon ('Birds of India,' vol. i. p. 260) 

 on the Palaeornis rosa, in which the young are more like the female 

 than the male. See Audubon ('Ornith. Biograph.' vol. ii. p. 475) on. 

 the two sexes and the young of Columba passerina. 



