84 
SEXUAL SELECTION: BIRDS. 
PakT* 
dered more and more complete, until a perfect double 
moult was acquired. A gradation can also be shewn 1° 
exist in the length of time during which eitl* el " 
annual plumage is retained; so that the one mig^ 
come to bo retained for the whole'year, the other beM 
completely lost. Thus the Machetes pugnax retail 
his raff in the spring for barely two months. Tb e 
male widow-bird ( Cliera progne) acquires in Natal ^ 
fine plumage and long tail-feathers in December ° r 
January and loses them in March; so that they a 1 ' 0 
retained during only about three months. Most specif 
which undergo a double moult keep their ornament 111 , 
feathers for about six months. The male, however, ° ! 
the wild Oallus bankiva retains his neck-hackles 
nine or ten months ; and when these are cast off, 
underlying black feathers on the neck are fully expo? 1 - 
to view. But with the domesticated descendant of tl )ls 
species, the neck-hackles of the male are immediate!) 
replaced by new ones; so that we here see, with resp ect 
to part of the plumage, a double moult changed und ef 
domestication into a single moult. 77 
4 ho common drake (Anas boschas ) is well known aft 0 * 
the breeding-season to lose his male plumage for 11 
period of three months, during which time he assun 3 ^ 
that of the female. The male pintail-duck 
acuta) loses his plumage for the shorter period 0 
six weeks or two months ; and Montagu remarks tb® 
“ For the foregoing statements in regard to partial moults, an<l ^ 
old males retaining their nuptial plumage, sec Jenlon, on bustards < 
plovers, in ‘ Birds ol India,’ vol. iii. p. (;i7, 637, 709, 711. Also Sb, 
in ‘ Land and Water,’ 1867, p. 84. Oil the Yidua, ‘ Ibis,’ vol. iii- l 8 " i 
p. 133. On the Drongo shrikes, Jordon, ibid. vol. i. p. 435. On w 
vernal moult of the Herodias bubulcus. Sir. S. S. Allen, in ‘ Ibis,’ l S6 J 
p. 33. On Gallus lanhiva, Blytli, in 1 Annals and Mag. of Nat. B is ,„ 
vol. i. 1848, p. 455 ; see, also, on this subject, my ‘Variation of 
under Domestication,’ vol. i. p. 236. 
