84 
SEXUAL selection: bieds. 
Part IL 
dered more and more complete, until a perfect double 
moult was acquired. A gradation can also be shewn to 
exist in the length of time during which either 
annual plumage is retained; so that the one might 
come to be retained for the whole" year, the other being 
completely lost. Thus the Machetes jpugnax retains 
his ruff in the spring for barely tvYO months. The 
male widow-bird {Chera ^rogne) acquires in Natal his 
fine plumage and long tail-feathers in December or 
January and loses them in March ; so that they are 
retained during only about three months. Most species 
which undergo a double moult keep their ornamental 
feathers for about six months. The male, however, of 
the wild Gallus hanMva retains his neck-hackles for 
nine or ten months ; and when these are cast off, the 
underlying black feathers on the neck are fully exposed 
to view. But with the domesticated descendant of this 
species, the neck-hackles of the male are immediately 
replaced by new ones ; so that we here see, with respect 
to part of the plumage, a double moult changed under 
domestication into a single moult.^^ 
The common drake (Atos loschas) is well known after 
the breeding-season to lose his male plumage for a 
period of three months, duriug which time he assumes 
that of the female. The male pintail-duck (Anas^ 
acuta) loses his plumage for the shorter period of 
six weeks or two months ; and Montagu remarks that 
For tlie foregoing statements in regard to partial monlts, and on 
old males retaining their nuptial plumage, see Jerdon, on bustards and 
plovers, in ‘ Birds of India,’ vol. iii. p. 617, 637, 709, 711. Also Blytli 
in ‘Land and Water,’ 1867, p. 84. On The Vidua, ‘Ibis,’ vol. iii. 1861, 
p. 133. On the Drongo shrikes, Jerdon, ibid. vol. i. p. 435. On the 
vernal moult of the Herodlas hiibulciis, Mr. S. S. Allen, in ‘ Ibis,’ 1863, 
p. 33. On Gallus hanldva, Blyth, in ‘ Annals and Mag. of Nat. Hist.’ 
vol. i. 1848, p. 455 ; see, also, on this subject, my ‘ Variation of Animals 
under Domestication,’ vol. i. p. 236. 
