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Descent of Man [ 1871]

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Bullseye
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« Reply #135 on: February 09, 2009, 03:14:29 pm »

The foregoing remarks relate to the secondary wing-feathers, but the
primary wing-feathers, which in most gallinaceous birds are
uniformly coloured, are in the Argus pheasant equally wonderful.
They are of a soft brown tint with numerous dark spots, each of
which consists of two or three black dots with a surrounding dark
zone. But the chief ornament is a space parallel to the dark-blue
shaft, which in outline forms a perfect second feather lying within
the true feather. This inner part is coloured of a lighter chestnut,
and is thickly dotted with minute white points. I have shewn this
feather to several persons, and many have admired it even more than
the ball and socket feathers, and have declared that it was more
like a work of art than of nature. Now these feathers are quite hidden
on all ordinary occasions, but are fully displayed, together with
the long secondary feathers, when they are all expanded together so as
to form the great fan or shield.
  The case of the male Argus pheasant is eminently interesting,
because it affords good evidence that the most refined beauty may
serve as a sexual charm, and for no other purpose. We must conclude
that this is the case, as the secondary and primary wing-feathers
are not at all displayed, and the ball and socket ornaments are not
exhibited in full perfection until the male assumes the attitude of
courtship. The Argus pheasant does not possess brilliant colours, so
that his success in love appears to depend on the great size of his
plumes, and on the elaboration of the most elegant patterns. Many will
declare that it is utterly incredible that a female bird should be
able to appreciate fine shading and exquisite patterns, It is
undoubtedly a marvellous fact that she should possess this almost
human degree of taste. He who thinks that he can safely gauge the
discrimination and taste of the lower animals may deny that the female
Argus pheasant can appreciate such refined beauty; but he will then be
compelled to admit that the extraordinary attitudes assumed by the
male during the act of courtship, by which the wonderful beauty of his
plumage is fully displayed, are purposeless; and this is a
conclusion which I for one will never admit.
  Although so many pheasants and allied gallinaceous birds carefully
display their plumage before the females, it is remarkable, as Mr.
Bartlett informs me, that this is not the case with the
dull-coloured Eared and Cheer pheasants (Crossoptilon auritum and
Phasianus wallichii); so that these birds seem conscious that they
have little beauty to display. Mr. Bartlett has never seen the males
of either of these species fighting together, though he has not had
such good opportunities for observing the Cheer or the Eared pheasant.
Mr. Jenner Weir, also, finds that all male birds with rich or
strongly-characterised plumage are more quarrelsome than the
dull-coloured species belonging to the same groups. The goldfinch, for
instance, is far more pugnacious than the linnet, and the blackbird
than the thrush. Those birds which undergo a seasonal change of
plumage likewise become much more pugnacious at the period when they
are most gaily ornamented. No doubt the males of some
obscurely-coloured birds fight desperately together, but it appears
that when sexual selection has been highly influential, and has
given bright colours to the males of any species, it has also very
often given a strong tendency to pugnacity. We shall meet with
nearly analogous cases when we treat of mammals. On the other hand,
with birds the power of song and brilliant colours have rarely been
both acquired by the males of the same species; but in this case the
advantage gained would have been the same, namely, success in charming
the female. Nevertheless it must be owned that the males of several
brilliantly coloured birds have had their feathers specially
modified for the sake of producing instrumental music, though the
beauty of this cannot be compared, at least according to our taste,
with that of the vocal music of many songsters.
  We will now turn to male birds which are not ornamented in any
high degree, but which nevertheless display during their courtship
whatever attractions they may possess. These cases are in some
respects more curious than the foregoing, and have been but little
noticed. I owe the following facts to Mr. Weir, who has long kept
confined birds of many kinds, including all the British Fringillidae
and Emberizidae. The facts have been selected from a large body of
valuable notes kindly sent me by him. The bullfinch makes his advances
in front of the female, and then puffs out his breast, so that many
more of the crimson feathers are seen at once than otherwise would
be the case. At the same time he twists and bows his black tail from
side to side in a ludicrous manner. The male chaffinch also stands
in front of the female, thus showing his red breast and "blue bell,"
as the fanciers call his head; the wings at the same time being
slightly expanded, with the pure white bands on the shoulders thus
rendered conspicuous. The common linnet distends his rosy breast,
slightly expands his brown wings and tail, so as to make the best of
them by exhibiting their white edgings. We must, however, be
cautious in concluding that the wings are spread out solely for
display, as some birds do so whose wings are not beautiful. This is
the case with the domestic ****, but it is always the wing on the side
opposite to the female which is expanded, and at the same time scraped
on the ground. The male gold-finch behaves differently from all
other finches: his wings are beautiful, the shoulders being black,
with the dark-tipped wing-feathers spotted with white and edged with
golden yellow. When he courts the female, he sways his body from
side to side, and quickly turns his slightly expanded wings first to
one side, then to the other, with a golden flashing effect. Mr. Weir
informs me that no other British finch turns thus from side to side
during his courtship, not even the closely-allied male siskin, for
he would not thus add to his beauty.
  Most of the British buntings are plain coloured birds; but in the
spring the feathers on the head of the male reed-bunting (Emberiza
schaeniculus) acquire a fine black colour by the abrasion of the dusky
tips; and these are erected during the act of courtship. Mr. Weir
has kept two species of Amadina from Australia: the A. castanotis is a
very small and chastely coloured finch, with a dark tail, white
rump, and jet-black upper tail-coverts, each of the latter being
marked with three large conspicuous oval spots of white.* This
species, when courting the female, slightly spreads out and vibrates
these parti-coloured tail-coverts in a very peculiar manner. The
male Amadina lathami behaves very differently, exhibiting before the
female his brilliantly spotted breast, scarlet rump, and scarlet upper
tail-coverts. I may here add from Dr. Jerdon that the Indian bulbul
(Pycnonotus hoemorrhous) has its under tail-coverts of a crimson
colour, and these, it might be thought could never be well
exhibited; but the bird "when excited often spreads them out laterally
so that they can be seen even from above."*(2) The crimson under
tail-coverts of some other birds as with one of the woodpeckers, Picus
major, can be seen without any such display. The common pigeon has
iridescent feathers on the breast, and every one must have seen how
the male inflates his breast whilst courting the female, thus
shewing them off to the best advantage. One of the beautiful
bronze-winged pigeons of Australia (Ocyphaps lophotes) behaves, as
described to me by Mr. Weir, very differently: the male, whilst
standing before the female, lowers his head almost to the ground,
spreads out and raises his tail, and half expands his wings. He then
alternately and slowly raises and depresses his body, so that the
iridescent metallic feathers are all seen at once, and glitter in
the sun.

  * For the description of these birds, see Gould's Handbook of the
Birds of Australia, vol. i., 1865, p. 417.
  *(2) Birds of India, vol. ii., p. 96.

  Sufficient facts have now been given to shew with what care male
birds display their various charms, and this they do with the utmost
skill. Whilst preening their feathers, they have frequent
opportunities for admiring themselves, and of studying how best to
exhibit their beauty. But as all the males of the same species display
themselves in exactly the same manner, it appears that actions, at
first perhaps intentional, have become instinctive. If so, we ought
not to accuse birds of conscious vanity; yet when we see a peacock
strutting about, with expanded and quivering tail-feathers, he seems
the very emblem of pride and vanity.
  The various ornaments possessed by the males are certainly of the
highest importance to them, for in some cases they have been
acquired at the expense of greatly impeded powers of flight or of
running. The African night-jar (Cosmetornis), which during the
pairing-season has one of its primary wing-feathers developed into a
streamer of very great length, is thereby much retarded in its flight,
although at other times remarkable for its swiftness. The "unwieldy
size" of the secondary wing-feather of the male Argus pheasant is said
"almost entirely to deprive the bird of flight." The fine plumes of
male birds of paradise trouble them during a high wind. The
extremely long tail-feathers of the male widow-birds (Vidua) of
Southern Africa render "their flight heavy;" but as soon as these
are cast off they fly as well as the females. As birds always breed
when food is abundant, the males probably do not suffer much
inconvenience in searching for food from their impeded powers of
movement; but there can hardly be a doubt that they must be much
more liable to be struck down by birds of prey. Nor can we doubt
that the long train of the peacock and the long tail and wing-feathers
of the Argus pheasant must render them an easier prey to any
prowling tiger-cat than would otherwise be the case. Even the bright
colours of many male birds cannot fail to make them conspicuous to
their enemies of all kinds. Hence, as Mr. Gould has remarked, it
probably is that such birds are generally of a shy disposition, as
if conscious that their beauty was a source of danger, and are much
more difficult to discover or approach, than the sombre coloured and
comparatively tame females or than the young and as yet unadorned
males.*

  * On the Cosmetornis, see Livingstone's Expedition to the Zambesi,
1865, p. 66. On the Argus pheasant, Jardine's Nat. Hist. Lib.:
Birds, vol. xiv., p. 167. On birds of paradise, Lesson, quoted by
Brehm, Thierleben, B. iii., s. 325. On the widow-bird, Barrow's
Travels in Africa, vol. i., p. 243, and Ibis. vol., iii., 1861 p. 133.
Mr. Gould, on the shyness of male birds, Handbook to Birds of
Australia, vol. i., 1865, pp. 210, 457

  It is a more curious fact that the males of some birds which are
provided with special weapons for battle, and which in a state of
nature are so pugnacious that they often kill each other, suffer
from possessing certain ornaments. ****-fighters trim the hackles
and cut off the combs and gills of their cocks; and the birds are then
said to be dubbed. An undubbed bird, as Mr. Tegetmeier insists, "is at
a fearful disadvantage; the comb and gills offer an easy hold to his
adversary's beak, and as a **** always strikes where he holds, when
once he has seized his foe, he has him entirely in his power. Even
supposing that the bird is not killed, the loss of blood suffered by
an undubbed **** is much greater than that sustained by one that has
been trimmed."* Young turkey-cocks in fighting always seize hold of
each other's wattles; and I presume that the old birds fight in the
same manner. It may perhaps be objected that the comb and wattles
are not ornamental, and cannot be of service to the birds in this way;
but even to our eyes, the beauty of the glossy black Spanish **** is
much enhanced by his white face and crimson comb; and no one who has
ever seen the splendid blue wattles of the male tragopan pheasant
distended in courtship can for a moment doubt that beauty is the
object gained. From the foregoing facts we clearly see that the plumes
and other ornaments of the males must be of the highest importance
to them; and we further see that beauty is even sometimes more
important than success in battle.

  * Tegetmeier, The Poultry Book, 1866, p. 139.



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