The Descent of Man, Charles Darwin [top 100 books of all time checklist txt] 📗

long tail-feathers in December or January, and loses them in March; so that they are retained only for about three months. Most species, which undergo a double moult, keep their ornamental feathers for about six months. The male, however, of the wild Gallus bankiva retains his neck-hackles for nine or ten months; and when these are cast off, the underlying black feathers on the neck are fully exposed to view. But with the domesticated descendant of this species, the neck-hackles of the male are immediately replaced by new ones; so that we here see, as to part of the plumage, a double moult changed under domestication into a single moult. (82. For the foregoing statements in regard to partial moults, and on old males retaining their nuptial plumage, see Jerdon, on bustards and plovers, in ‘Birds of India,’ vol. iii. pp. 617, 637, 709, 711. Also Blyth in ‘Land and Water,’ 1867, p. 84. On the moulting of Paradisea, see an interesting article by Dr. W. Marshall, ‘Archives Neerlandaises,’ tom. vi. 1871. On the Vidua, ‘Ibis,’ vol. iii. 1861, p. 133. On the Drongo- shrikes, Jerdon, ibid. vol. i. p. 435. On the vernal moult of the Herodias bubulcus, Mr. S.S. Allen, in ‘Ibis,’ 1863, p. 33. On Gallus bankiva, Blyth, in ‘Annals and Mag. of Natural History,’ vol. i. 1848, p. 455; see, also, on this subject, my ‘Variation of Animals under Domestication,’ vol. i. p. 236.)

The common drake (Anas boschas), after the breeding-season, is well known to lose his male plumage for a period of three months, during which time he assumes that of the female. The male pin-tail duck (Anas acuta) loses his plumage for the shorter period of six weeks or two months; and Montagu remarks that “this double moult within so short a time is a most extraordinary circumstance, that seems to bid defiance to all human reasoning.” But the believer in the gradual modification of species will be far from feeling surprise at finding gradations of all kinds. If the male pin-tail were to acquire his new plumage within a still shorter period, the new male feathers would almost necessarily be mingled with the old, and both with some proper to the female; and this apparently is the case with the male of a not distantly-allied bird, namely the Merganser serrator, for the males are said to “undergo a change of plumage, which assimilates them in some measure to the female.” By a little further acceleration in the process, the double moult would be completely lost. (83. See Macgillivray, ‘Hist. British Birds’ (vol. v. pp. 34, 70, and 223), on the moulting of the Anatidae, with quotations from Waterton and Montagu. Also Yarrell, ‘History of British Birds,’ vol. iii. p. 243.)

Some male birds, as before stated, become more brightly coloured in the spring, not by a vernal moult, but either by an actual change of colour in the feathers, or by their obscurely-coloured deciduary margins being shed. Changes of colour thus caused may last for a longer or shorter time. In the Pelecanus onocrotalus a beautiful rosy tint, with lemon-coloured marks on the breast, overspreads the whole plumage in the spring; but these tints, as Mr. Sclater states, “do not last long, disappearing generally in about six weeks or two months after they have been attained.” Certain finches shed the margins of their feathers in the spring, and then become brighter coloured, while other finches undergo no such change. Thus the Fringilla tristis of the United States (as well as many other American species) exhibits its bright colours only when the winter is past, whilst our goldfinch, which exactly represents this bird in habits, and our siskin, which represents it still more closely in structure, undergo no such annual change. But a difference of this kind in the plumage of allied species is not surprising, for with the common linnet, which belongs to the same family, the crimson forehead and breast are displayed only during the summer in England, whilst in Madeira these colours are retained throughout the year. (84. On the pelican, see Sclater, in ‘Proc. Zool. Soc.’ 1868, p. 265. On the American finches, see Audubon, ‘Ornithological Biography,’ vol. i. pp. 174, 221, and Jerdon, ‘Birds of India,’ vol. ii. p. 383. On the Fringilla cannabina of Madeira, Mr. E. Vernon Harcourt, ‘Ibis,’ vol. v. 1863, p. 230.)

DISPLAY BY MALE BIRDS OF THEIR PLUMAGE.

Ornaments of all kinds, whether permanently or temporarily gained, are sedulously displayed by the males, and apparently serve to excite, attract, or fascinate the females. But the males will sometimes display their ornaments, when not in the presence of the females, as occasionally occurs with grouse at their balz-places, and as may be noticed with the peacock; this latter bird, however, evidently wishes for a spectator of some kind, and, as I have often seen, will shew off his finery before poultry, or even pigs. (85. See also ‘Ornamental Poultry,’ by Rev. E.S. Dixon, 1848, p. 8.) All naturalists who have closely attended to the habits of birds, whether in a state of nature or under confinement, are unanimously of opinion that the males take delight in displaying their beauty. Audubon frequently speaks of the male as endeavouring in various ways to charm the female. Mr. Gould, after describing some peculiarities in a male humming- bird, says he has no doubt that it has the power of displaying them to the greatest advantage before the female. Dr. Jerdon (86. ‘Birds of India,’ introduct., vol. i. p. xxiv.; on the peacock, vol. iii. p. 507. See Gould’s ‘Introduction to Trochilidae,’ 1861, pp. 15 and 111.) insists that the beautiful plumage of the male serves “to fascinate and attract the female.” Mr. Bartlett, at the Zoological Gardens, expressed himself to me in the strongest terms to the same effect.

[Fig. 50. Rupicola crocea, male (T.W. Wood).]

It must be a grand sight in the forests of India “to come suddenly on twenty or thirty pea-fowl, the males displaying their gorgeous trains, and strutting about in all the pomp of pride before the gratified females.” The wild turkey-cock erects his glittering plumage, expands his finely- zoned tail and barred wing-feathers, and altogether, with his crimson and blue wattles, makes a superb, though, to our eyes, grotesque appearance. Similar facts have already been given with respect to grouse of various kinds. Turning to another Order: The male Rupicola crocea (Fig. 50) is one of the most beautiful birds in the world, being of a splendid orange, with some of the feathers curiously truncated and plumose. The female is brownish-green, shaded with red, and has a much smaller crest. Sir R. Schomburgk has described their courtship; he found one of their meeting- places where ten males and two females were present. The space was from four to five feet in diameter, and appeared to have been cleared of every blade of grass and smoothed as if by human hands. A male “was capering, to the apparent delight of several others. Now spreading its wings, throwing up its head, or opening its tail like a fan; now strutting about with a hopping gait until tired, when it gabbled some kind of note, and was relieved by another. Thus three of them successively took the field, and then, with self-approbation, withdrew to rest.” The Indians, in order to obtain their skins, wait at one of the meeting-places till the birds are eagerly engaged in dancing, and then are able to kill with their poisoned arrows four or five males, one after the other. (87. ‘Journal of R. Geograph. Soc.’ vol. x. 1840, p. 236.) With birds of paradise a dozen or more full-plumaged males congregate in a tree to hold a dancing-party, as it is called by the natives: and here they fly about, raise their wings, elevate their exquisite plumes, and make them vibrate, and the whole tree seems, as Mr. Wallace remarks, to be filled with waving plumes. When thus engaged, they become so absorbed that a skilful archer may shoot nearly the whole party. These birds, when kept in confinement in the Malay Archipelago, are said to take much care in keeping their feathers clean; often spreading them out, examining them, and removing every speck of dirt. One observer, who kept several pairs alive, did not doubt that the display of the male was intended to please the female. (88. ‘Annals and Mag. of Nat. Hist.’ vol. xiii. 1854, p. 157; also Wallace, ibid. vol. xx. 1857, p. 412, and ‘The Malay Archipelago,’ vol. ii. 1869, p. 252. Also Dr. Bennett, as quoted by Brehm, ‘Thierleben,’ B. iii. s. 326.)

[Fig. 51. Polyplectron chinquis, male (T.W. Wood).]

The Gold and Amherst pheasants during their courtship not only expand and raise their splendid frills, but twist them, as I have myself seen, obliquely towards the female on whichever side she may be standing, obviously in order that a large surface may be displayed before her. (89. Mr. T.W. Wood has given (‘The Student,’ April 1870, p. 115) a full account of this manner of display, by the Gold pheasant and by the Japanese pheasant, Ph. versicolor; and he calls it the lateral or one-sided display.) They likewise turn their beautiful tails and tail-coverts a little towards the same side. Mr. Bartlett has observed a male Polyplectron (Fig. 51) in the act of courtship, and has shewn me a specimen stuffed in the attitude then assumed. The tail and wing-feathers of this bird are ornamented with beautiful ocelli, like those on the peacock’s train. Now when the peacock displays himself, he expands and erects his tail transversely to his body, for he stands in front of the female, and has to shew off, at the same time, his rich blue throat and breast. But the breast of the Polyplectron is obscurely coloured, and the ocelli are not confined to the tail-feathers. Consequently the Polyplectron does not stand in front of the female; but he erects and expands his tail-feathers a little obliquely, lowering the expanded wing on the same side, and raising that on the opposite side. In this attitude the ocelli over the whole body are exposed at the same time before the eyes of the admiring female in one grand bespangled expanse. To whichever side she may turn, the expanded wings and the obliquely-held tail are turned towards her. The male Tragopan pheasant acts in nearly the same manner, for he raises the feathers of the body, though not the wing itself, on the side which is opposite to the female, and which would otherwise be concealed, so that nearly all the beautifully spotted feathers are exhibited at the same time.

[Fig. 52. Side view of male Argus pheasant, whilst displaying before the female. Observed and sketched from nature by T.W. Wood.]

The Argus pheasant affords a much more remarkable case. The immensely developed secondary wing-feathers are confined to the male; and each is ornamented with a row of from twenty to twenty-three ocelli, above an inch in diameter. These feathers are also elegantly marked with oblique stripes and rows of spots of a dark colour, like those on the skin of a tiger and leopard combined. These beautiful ornaments are hidden until the male shows himself off before the female. He then erects his tail, and expands his wing-feathers into a great, almost upright, circular fan or shield, which is carried in front of the body. The neck and head are held on one side, so that they are concealed by the fan; but the bird