x COLOURS AND ORNAMENTS CHARACTERISTIC OF SEX 2S7 
charmed or excited by the fine display of plumage by the 
males; but there is no proof whatever that slight differences 
in that display have any effect in determining their choice of 
a partner. 
Display of Decorative Plumage. 
The extraordinary manner in which most birds display 
their plumage at the time of courtship, apparently with the 
full knowledge that it is beautiful, constitutes one of Mr. 
Darwin’s strongest arguments. It is, no doubt, a very curious 
and interesting phenomenon, and indicates a connection be¬ 
tween the exertion of particular muscles and the develop¬ 
ment of colour and ornament; but, for the reasons just given, 
it does not prove that the ornament has been developed by 
female choice. During excitement, and when the organism 
develops superabundant energy, many animals find it pleasur¬ 
able to exercise their various muscles, often in fantastic ways, 
as seen in the gambols of kittens, lambs, and other young 
animals. But at the time of pairing, male birds are in a 
state of the most perfect development, and possess an 
enormous store of vitality ; and under the excitement of the 
sexual passion they perform strange antics or rapid flights, as 
much probably from an internal impulse to motion and exertion 
as with any desire to please their mates. Such are the rapid 
descent of the snipe, the soaring and singing of the lark, and 
the dances of the cock-of-the-rock and of many other birds. 
It is very suggestive that similar strange movements are 
performed by many birds which have no ornamental plumage 
to display. Goatsuckers, geese, carrion vultures, and many 
other birds of plain plumage have been observed to dance, 
spread their wings or tails, and perform strange love-antics. 
The courtship of the great albatross, a most unwieldy and 
dull coloured bird, has been thus described by Professor 
Moseley: “The male, standing by the female on the nest, 
raises his wings, spreads his tail and elevates it, throws up his 
head with the bill in the air, or stretches it straight out, or 
forwards, as far as he can, and then utters a curious cry.” 1 Mr. 
Jenner Weir informs me that “the male blackbird is full of 
action, spreads out his glossy wing and tail, turns his rich golden 
1 Notes of a Naturalist on the Challenger. 
