DOUBLE ANNUAL MOULT. 
85 
Ci Up. 
XIII. 
« ^’ s double moult within so short a time is a most 
„ ^ti'aordinary circumstance, that seems to bid defiance 
0 all human reasoning.” But lie who believes in the 
o a dual modification of species will be far from feeling 
11 prise at finding gradations of all kinds. If the male 
Pintail 
o o 
^ were to acquire his new plumage within a still 
l °rter period, the new male feathers would almost 
^essarily be mingled with the old, and both with 
e lne P r oper to the female ; and this apparently is the 
t j^ e with the male of a not distantly-allied bird, namely 
<< 6 df erganser serrator, for the males are said to 
<; ^ ll dergo a change of plumage, which assimilates them 
tsh 
a ecel 
^pletely lost. 78 
some measure to the female.” By a little further 
Oration in the process, the double moult would be 
'ome 
b 8 
coloured in the spring, not by a vernal moult, 
0j , , either by an actual change of colour in the feathers, 
sli 7 t ' 1 “ r obscurely-coloured deciduary margins being 
j 0 6 ‘ Changes of colour thus caused may last for a 
a ^ er °r shorter time. With the Pelecanus onocrotalus 
br 7 aUtiful rosy tint, with lemon-coloured marks on the 
th ast ’ overspreads the whole plumage in the spring ; hut 
“ 7° t * Uts ’ as ^ r - Sclater states, “do not last long, dis- 
(( appearing generally in about six weeks or two months 
th e 6r the > T Pave been attained. 
- marc 
male birds, as before stated, become more 
Certain finches shed 
KJ 1 tUtJir leailltUC) 111 Wi <3 Q|niug, uuu w 
'^liter-coloured, while other finches undergo no 
Sb t ' Jlli,n K e - Thus the Fringilla tridis of the United 
lju . es _( as well as many other American species), ex- 
tyjj. 1 , 8 its bright colours only when the winter is past, 
1 st our goldfinch, which exactly represents this bird 
on tj. ee VlaeglUivray, 1 Hist. British Birds ’ (vol. v. p. 31, 70, and 223), 
Xloj^ ^Woulting 0 f f| ie Anatidss, with quotations from M aterton and 
SB- Also Yarrell, * Hist, of British Birds,’ vol. iii. p. 243. 
