376 TROPICAL NATURE v 
tion, and what may be termed male selection, will tend to 
give them the advantage in the struggle for existence, and 
thus the fullest plumage and the finest colours will be trans- 
mitted, and tend to advance in each succeeding generation. 
Theory of Display of Ornaments by Males 
The full and interesting account given by Mr. Darwin of 
the colours and habits of male and female birds (Descent of 
Man, chaps. xiii. and xiv.), proves that in most, if not in 
all cases, the male birds fully display their ornamental plum- 
age before the females or in rivalry with each other; but on 
the essential point of whether the female’s choice is deter- 
mined by minute differences in these ornaments or in their 
colours, there appears to be an entire absence of evidence. 
In the section on “Preference for particular Males by the 
Females,” the facts quoted show indifference to colour, except 
that some colour similar to their own seems to be preferred. 
But in the case of the hen canary who chose a greenfinch in 
preference to either chaffinch or goldfinch, gay colours had 
evidently no preponderating attraction. There is some evi- 
dence adduced that female birds may, and probably do, 
choose their mates, but none whatever that the choice is 
determined by difference of colour; and no less than three 
eminent breeders informed Mr. Darwin that they “did not 
believe that the females prefer certain males on account of 
the beauty of their plumage.” Again, Mr. Darwin himself 
says: “Asa general rule colour appears to have little influ- 
ence on the pairing of pigeons.” The oft-quoted case of Sir 
R. Heron’s pea-hens, which preferred an “old pied cock” to 
those normally coloured, is a very unfortunate one, because 
pied birds are just those that are not favoured in a state of 
nature, or the breeds of wild animals would become as varied 
and mottled as our domestic varieties. If such irregular 
fancies were not rare exceptions, the production of definite 
colours and patterns by the choice of the female birds, or in 
any other way, would be impossible. 
There remains, however, to be accounted for, the remark. 
able fact of the display by the male of each species of its 
peculiar beauties of plumage and colour—a display which Mr. 
